Physics Calculators
Free calculators for force, kinematics, Ohm's law, projectile motion, flywheel energy, speed of light, and speed of sound. All equations with SI units.
Acceleration in the Electric Field Calculator
Find a = qE/m for an electron, proton, alpha or custom charge, from a field or from plate voltage and gap, with speed, time and a relativistic check. Free.
Angle of Banking Calculator
Calculate the ideal banking angle tan(theta) = v^2/(r g), the safe speed range with friction, the required radius, and railway cant and deficiency. Free.
Angular Displacement Calculator
Find angular displacement with theta = w0 t + 1/2 a t^2, solve any rotation variable, get arc length s = r theta, and convert rad, deg and rev. Free.
Angular Frequency Calculator
Convert frequency, period or rpm to angular frequency omega = 2 pi f, plus omega for springs, pendulums, LC circuits and mains. Free, with a chart.
Ballistic Coefficient Calculator
Calculate ballistic coefficient from mass, diameter and drag, convert to a G1 style BC with form factor, and find speed retained over distance. Free.
Car Center of Mass Calculator
Find a car's center of mass from axle or side weights and a lift test, then get weight distribution and the rollover threshold with a diagram. Free.
Car Crash Calculator
Explore two-vehicle collision physics: momentum, delta-v, energy lost and barrier-equivalent speed, plus barrier drop height. Educational only. Free.
Car Jump Distance Calculator
Calculate ramp jump distance, air time, peak height and landing speed from launch speed and angle, or the speed needed to clear a gap. Physics only. Free.
Displacement Calculator
Calculate displacement and distance from coordinates, multi-leg paths or velocity, time and acceleration, with direction angle and charts. Free.
Drift Velocity Calculator
Calculate the drift velocity of electrons in a wire from current, diameter and material, find transit time along the wire, or use mobility, v = μE. Free.
EIRP Calculator - Effective Isotropic Radiated Power
Calculate EIRP in dBm, dBW and watts from transmit power, antenna gain and cable loss, convert to ERP, and find power density and link budget. Free.
Energy Density of Fields Calculator
Find electric and magnetic energy density, u = ½ε₀E² and B²/(2μ₀), total energy in a volume, or the field needed for a given energy density. Free.
Free Fall Calculator
Calculate free fall drop time, impact speed and height from any one known value, with planet gravity presets and speed and height charts versus time. Free.
Free Fall with Air Resistance Calculator
Calculate fall speed and distance with quadratic air drag using the tanh solution, plus terminal velocity, 95 percent time and vacuum comparison. Free.
Friction Calculator
Calculate static and kinetic friction force F = mu N on flat ground or a slope, check whether an object slips and find the force to start it moving. Free.
Hooke's Law Calculator
Solve Hooke's law F = kx for force, spring constant or extension, combine springs in series or parallel, and check the elastic limit. Free, with charts.
Inclined Plane Calculator
Calculate acceleration, time and speed at the bottom of a ramp with friction, the push force up a ramp, ramp length and the angle of repose. Free.
kg to Newtons Calculator
Convert kg to newtons with W = mg, or newtons back to kg and pounds to lbf. Choose Earth, Moon, Mars or a custom g and see a weight table. Free.
Lorentz Force Calculator
Calculate the Lorentz force F = q(E + v × B), its components and magnitude, the angle to the field, plus orbit radius and cyclotron frequency. Free.
Newton's Second Law Calculator
Solve F = ma for force, mass or acceleration in N, lbf, dyne, kg, lb and g, add several forces to a net force, and find weight on other worlds. Free.
Newton's Third Law Calculator
Find the equal and opposite forces between two bodies, each body's own acceleration and velocity, collision forces and rocket thrust. Free, with charts.
Polar Moment of Inertia Calculator
Calculate the polar moment of inertia J of solid and hollow shafts and other sections in mm4 and in4, with torsion shear stress and twist angle. Free.
Pounds per Square Inch Calculator
Calculate psi from force and area, convert psi to kPa, bar, atm and mmHg, and switch between gauge and absolute pressure for tires and tanks. Free.
Power-to-Weight Ratio Calculator
Calculate power-to-weight ratio in hp/lb, W/kg, kW/kg and hp per tonne, compare two vehicles or cyclists, and estimate 0-60 and quarter mile times. Free.
Pressure Calculator
Solve pressure, force or area with P = F/A, or fluid pressure, density or depth with P = rho g h. Pa, kPa, bar, atm, psi, torr and a depth chart. Free.
Quarter Mile Calculator
Estimate quarter mile ET and trap speed from weight and horsepower, find the power needed for a target time, or use constant acceleration. Free estimates.
Reduced Mass Calculator
Find the reduced mass mu = m1 m2/(m1+m2) of two bodies, solve for a missing mass, get orbital periods and the hydrogen atom electron-proton value. Free.
Rolling Resistance Calculator
Calculate rolling resistance force F = Crr m g cos(slope), power at speed, energy per km and coast-down distance, with an air drag option. Free.
Signal-to-Noise Ratio Calculator
Calculate signal-to-noise ratio in dB from power levels or RMS amplitudes, convert SNR to bits of resolution, and find the thermal noise floor kTB. Free.
Sled Ride Calculator
Calculate sled speed at the bottom of a slope, time taken and run-out distance on the flat with friction and optional air drag. Speed chart included.
Stopping Distance Calculator
Find reaction, braking and total stopping distance for any speed, road surface and grade using v squared over 2 mu g, with a chart. Educational physics.
SUVAT Calculator
Solve any SUVAT problem: pick the three quantities you know, get the other two, the equation used, a step-by-step solution and a velocity-time graph. Free.
Tension Calculator
Find rope tension for a hanging mass or elevator, an Atwood or table-pulley system, and two angled ropes, with diagrams, safety factor and charts. Free.
TNT Equivalent Calculator
Convert energy in joules, kWh or kcal to TNT equivalent in kg, tons, kilotons and megatons using 4.184 MJ per kg, or convert TNT back to energy. Free.
Trajectory Calculator
Calculate a projectile trajectory with launch height and optional linear or quadratic air drag, with a position table and flight path chart. Free.
Velocity Addition Calculator
Add velocities with the relativistic formula u = (v + w) / (1 + vw/c²), compare with Galilean addition, see rapidity, and handle sideways motion. Free.
Watt Converter
Convert watts to kW, MW, GW, mechanical and metric horsepower, BTU/h, kcal/h, ft lbf/s, dBm and dBW, with a full table and a dB gain and loss mode. Free.
Weight on Other Planets Calculator
Find your weight on the Moon, Mars, Jupiter and other planets from your Earth weight or mass, with a surface gravity table and comparison bars. Free.
Work and Power Calculator
Solve power, work or time with P = W/t and P = Fv, compare average and instantaneous power, size a lift in hp and kW, and price energy in kWh. Free.
Work Calculator
Solve work, force, distance or angle with W = F d cos(theta), find work against friction, gravity and springs, and see a work vs angle chart. Free.
Alfvén Velocity Calculator
Calculate the Alfvén velocity v_A = B/sqrt(mu0 rho) from field and ion density, find the Alfvén Mach number, or solve for the field. Free and instant.
Angular Acceleration Calculator
Calculate angular acceleration from a change in angular velocity and time, from torque and moment of inertia, or from tangential acceleration and radius.
Angular Momentum Calculator
Calculate angular momentum from L = I x omega or L = r m v sin theta, and find the new spin after a change in moment of inertia using conservation of L.
Angular Velocity Calculator
Convert angular velocity between rad/s, rpm and degrees per second, or find it from angle and time, linear speed and radius, or period or frequency.
Centrifugal Force Calculator
Calculate centrifugal force from mass, radius and rpm, rad/s, Hz or speed. Get RCF in g, acceleration, period and a force vs speed chart. Free.
Centripetal Force Calculator
Find centripetal force from speed, rpm or period, plus the ideal bank angle and loop normal forces. Includes acceleration in g and a force chart. Free.
Diffraction Grating Calculator
Solve the grating equation d sin(theta) = m lambda: diffraction angles of each order, lines per mm, maximum order and resolving power. Free.
Harmonic Wave Equation Calculator
Evaluate y(x,t) = A sin(kx - wt + phi) from wavelength and frequency or k and omega. Get wave speed, displacement at x and t, and a waveform chart. Free.
Index of Refraction Calculator
Find the refractive index from light speed, solve Snell's law for the refraction angle, and get the critical angle, with a materials table and ray diagram.
Kinetic Energy of a Pendulum Calculator
Find the kinetic energy, speed and tension of a pendulum at any angle from its release angle using energy conservation, plus max speed. Free chart.
Lens Maker Equation Calculator
Use the lensmaker's equation to find a lens focal length and power from its refractive index, two radii and thickness, or the radius a target needs. Free.
Linear Actuator Force Calculator
Find the force a linear actuator needs for a vertical, inclined or sliding load with a safety factor, plus screw torque, efficiency and motor power. Free.
Physical Pendulum Calculator
Find the period of a physical pendulum from its moment of inertia: rod, disk, ring or custom body, with a simple pendulum comparison and chart. Free.
Piston Force Calculator
Calculate piston force F = P x A from pressure and bore, with rod-side annulus force, bore sizing and cylinder speed. Hydraulic or pneumatic. Free.
Quiz: Potential Energy Calculator
Practice gravitational potential energy problems with random questions at three levels, instant answer checking, worked solutions and shareable seeds.
Recoil Energy Calculator
Find recoil velocity, recoil energy and momentum when a launcher fires a projectile, or the launcher mass for a recoil limit, using momentum conservation.
Rotational Kinetic Energy Calculator
Find rotational kinetic energy from moment of inertia and spin rate, from a shape, mass and size, or the total energy of a rolling body. Free.
Shear Wave Velocity Calculator
Calculate shear wave velocity Vs = sqrt(G/rho) from shear modulus, or from E and Poisson's ratio, with soil and rock presets and a Vs30 site class. Free.
Stiffness Matrix Calculator
Build the stiffness matrix of a 2-node bar or truss element at any angle, or a 2-DOF spring system, then solve displacements and reactions. Free.
Thin Lens Equation Calculator
Solve 1/f = 1/do + 1/di for converging and diverging lenses: image distance, magnification, real or virtual image, with a ray diagram and chart. Free.
Bullet Energy Calculator
Find projectile kinetic energy in joules and foot-pounds, plus momentum and Mach number, from mass and speed. Or solve speed from energy. Free.
Elastic Potential Energy Calculator
Find spring energy U = 1/2 k x^2, force, work between two stretches and launch speed, or solve for k or extension. Free, with a chart for each mode.
FPE Calculator - Foot-pounds of Energy
Find foot-pounds of energy from grains and fps, with joules, momentum and a 450240 shortcut check. Convert ft-lbf, J, cal, kcal and BTU. Free.
Gravitational Force Calculator
Calculate the gravitational force between two masses and each body's acceleration, or a planet's surface gravity, weight and escape speed. Free.
Impact Energy Calculator
Calculate impact energy from a drop height or speed, find impact speed, equivalent fall height and average impact force from stopping distance. Free.
Net Force Calculator
Add up to four forces along a line or at angles to find the net force, its direction, acceleration, equilibrium and the equilibriant, with friction. Free.
Normal Force Calculator
Calculate the normal force on a flat surface, an incline or in an elevator, plus weight, friction limit and whether an object slides. Free physics tool.
Potential Energy Calculator
Calculate gravitational potential energy U = mgh, solve for mass or height, or use -GMm/r for orbits. Get J, kJ, kWh, ft-lbf and a chart. Free.
Quiz: Net Force Calculator
Practice net force problems with random questions at three levels, instant answer checking, a full worked solution, a score streak and shareable seeds.
Time of Flight Calculator - Projectile Motion
Find projectile time of flight from speed, angle and launch height, or the flight time to reach a target range. Shows apex time and impact speed. Free.
Conservation of Momentum Calculator
Calculate final velocities, momentum and kinetic energy lost for a 1D collision (elastic, inelastic or custom e) or an explosion recoil. Free, with charts.
Horizontal Projectile Motion Calculator
Calculate time of flight, range, impact speed and angle for an object launched horizontally, or solve the launch speed from a measured distance. Free.
Impulse and Momentum Calculator
Calculate impulse, change in momentum, final velocity or average impact force from mass, velocity, force and contact time, with g-force and a chart. Free.
Magnitude of Acceleration Calculator
Find the magnitude of acceleration from ax, ay, az or from a velocity change. Get direction angles, direction cosines, g and ft/s2 with diagrams. Free.
Maximum Height Calculator - Projectile Motion
Calculate the maximum height of a projectile from speed, angle and launch height, with time to apex, or solve for the speed needed. Earth, Moon, Mars.
Momentum Calculator
Calculate linear momentum p = mv, or solve for mass or velocity. Get kg m/s, lb ft/s, kinetic energy, a relativistic check and a chart. Free.
Muzzle Velocity Calculator
Find projectile launch speed from energy and mass, chronograph gate timing, or a horizontal drop. Get m/s, ft/s, km/h, mph, energy, momentum and Mach.
Projectile Range Calculator
Calculate projectile range, flight time, max height and the best launch angle for any speed and launch height, or solve for the launch speed. Free.
Resultant Velocity Calculator
Add two velocities by speed and angle to get the resultant speed and direction, or solve a boat crossing a river for drift, time and heading. Free.
Terminal Velocity Calculator
Calculate terminal velocity with quadratic drag, v = sqrt(2mg / (rho Cd A)), plus speed and distance versus time and time to 90 and 99 percent. Free.
Specific Heat Calculator
Calculate heat energy with Q = mcΔT. Enter mass, specific heat, and temperature change to find joules, kilojoules, and kilocalories. Free and instant.
AC Wattage Calculator
Calculate AC real power (W), apparent power (VA), and reactive power (VAR) from voltage, current, and power factor. Free and instant results.
Darcy-Weisbach Calculator
Calculate pipe head loss, pressure drop, and flow rate via Darcy-Weisbach. Includes Swamee-Jain friction factor, Reynolds number, and Find Velocity mode.
Power Dissipation Calculator
Calculate electrical power dissipation using P=VI, P=I²R, or P=V²/R. Includes thermal analysis to find junction temperature and max safe power. Free.
Aperture Area Calculator
Calculate aperture area from diameter or f-number and focal length. Results in mm², cm², m², and in². Free online optics tool for cameras and telescopes.
Arrow Speed Calculator
Calculate arrow speed from IBO rating, draw weight, draw length, and arrow weight. Instantly shows kinetic energy, momentum, and hunting game class.
BMEP Calculator
Calculate BMEP from engine torque or power and RPM for 4-stroke and 2-stroke engines. Results in kPa, bar, and psi with performance rating. Free.
Electron Speed Calculator
Calculate electron velocity, Lorentz factor, and de Broglie wavelength from kinetic energy (eV/keV/MeV) or speed fraction. Relativistic and classical.
Flywheel Energy Storage Calculator
Calculate flywheel stored energy (E = ½Iω²), moment of inertia, angular velocity, tip speed, and specific energy. Free online tool for engineers.
Ground Speed Calculator
Calculate aircraft ground speed from true airspeed and wind vector, or convert distance and time to speed in knots, mph, km/h, and m/s. Free and instant.
Mechanical Advantage Calculator
Calculate mechanical advantage for levers, pulleys, and inclined planes. Enter arm lengths or dimensions to find MA, load force, and effort force.
Mirror Equation Calculator
Solve the mirror equation 1/v + 1/u = 1/f for concave and convex mirrors. Find image distance, magnification, focal length, and image type instantly.
Mohr's Circle Calculator
Find principal stresses, maximum shear stress, and principal plane angle from normal and shear stress using Mohr's circle formulas. Free, instant.
Piston Speed Calculator
Calculate mean piston speed (MPS) from stroke and RPM. Find engine stress level, bore:stroke ratio, and swept volume. Free, instant results.
Speed of Light Calculator
Calculate how long light takes to travel any distance, or how far light travels in any time. Converts c to km/s, mph, Mach, and more. Free, instant.
Speed of Sound Calculator
Calculate speed of sound in any gas at any temperature, or in water, steel, glass, and more. Returns m/s, km/h, mph, and knots. Free, instant.
Speed of Sound in Solids Calculator
Calculate longitudinal, shear, and extensional wave speeds in any solid from Young's modulus, Poisson's ratio, and density. 11 material presets. Free.
Speeds and Feeds Calculator
Calculate spindle RPM, feed rate, and metal removal rate for milling and turning. Supports metric (mm, m/min) and imperial (in, SFM). Free, instant.
Acceleration Calculator
Calculate acceleration, final velocity, or time using a = (v-u)/t. Results in m/s², g-force, and ft/s². Free online physics calculator with examples.
Kinetic Energy Calculator
Calculate kinetic energy from mass and velocity using KE = half mv2. Find mass or velocity from kinetic energy. Free online physics calculator.
Velocity Calculator
Calculate velocity, distance, or time using the formula v = d/t. Supports average velocity, acceleration, and various unit conversions. Free.
Force Calculator
Calculate force, mass, or acceleration using Newton's second law (F = ma). Solve for any one variable when the other two are known. Free, no signup.
Kinematic Equations Calculator
Solve SUVAT kinematic equations for displacement, velocity, acceleration, and time. Enter any three known values to find the missing fourth. Free.
Ohm's Law Calculator
Calculate voltage, current, resistance, and power using Ohm's Law. Enter any two values to solve for the remaining unknowns instantly. Free.
Projectile Motion Calculator
Calculate projectile range, maximum height, time of flight, and final velocity for any launch angle and initial speed. Shows full trajectory. Free.
Work, Energy & Power Calculator
Calculate mechanical work, kinetic energy, potential energy, and power. Solve for any variable using W=Fd, KE=½mv², PE=mgh, and P=W/t. Free.
Physics Calculators - Classical Mechanics and Electromagnetism, Solved
Physics calculators translate the fundamental laws of nature into numerical answers. Every calculator here applies the correct equation, shows all variable definitions with SI units, and walks through a worked example. Used by high school and undergraduate physics students.
Classical Mechanics
Force Calculator
Newton's second law F = ma, plus weight W = mg
Acceleration Calculator
a = (v−u)/t in m/s², g-force, and ft/s², plus displacement
Kinematics Calculator
All five SUVAT equations from any three known variables
Velocity Calculator
v = d/t in m/s, km/h, mph, and ft/s simultaneously
Projectile Motion Calculator
Max height, range, and time of flight for any launch angle and speed
Work, Energy & Power Calculator
W = Fd·cosθ, KE = ½mv², PE = mgh, and P = W/t
Kinetic Energy Calculator
KE = 0.5mv² in J, kJ, kcal, kWh, and BTU, plus momentum
Conservation of Momentum Calculator
Final velocities, momentum and energy lost in a 1D collision (elastic, inelastic or custom e), or the recoil speed after an explosion.
Horizontal Projectile Motion Calculator
Time of flight, range, impact speed and angle for a horizontal launch, or the launch speed from a measured landing distance.
Impulse and Momentum Calculator
Find the change in velocity from a force and contact time, or the average impact force from a velocity change, with g-force and a force versus time chart.
Magnitude of Acceleration Calculator
Find the size and direction of a 2D or 3D acceleration vector from its components or from a velocity change.
Maximum Height Calculator - Projectile Motion
Find a projectile's maximum height, time to apex and apex speed, or solve for the launch speed needed to reach a target height.
Momentum Calculator
Solve p = mv for momentum, mass or velocity, with kinetic energy and a relativistic validity check.
Muzzle Velocity Calculator
Find projectile launch speed from energy and mass, gate timing or a horizontal drop, with energy, momentum and Mach number.
Projectile Range Calculator
Find projectile range, flight time, max height and the best launch angle, or solve for the launch speed to hit a target distance.
Resultant Velocity Calculator
Add two velocity vectors for the resultant speed and direction, or solve a boat crossing a river for drift, crossing time and heading.
Terminal Velocity Calculator
Find the terminal velocity of a skydiver or falling object under quadratic drag, then see speed and distance versus time from rest.
Time of Flight Calculator - Projectile Motion
Find how long a projectile stays in the air, split into climb and descent, or the flight time to reach a target range.
Gravitational Force Calculator
Find the gravitational force between two masses and each body's acceleration, or a planet's surface gravity, weight and escape speed.
Net Force Calculator
Add several forces along a line or at angles to get the net force, direction, acceleration and equilibrium, with friction.
Normal Force Calculator
Find the normal force on a flat surface, an incline or in an elevator, with weight, friction limit and a slide check.
Quiz: Net Force Calculator
Practice net force problems at three levels with random questions, instant feedback, worked solutions, a streak and shareable seeds.
Bullet Energy Calculator
Kinetic energy in J and ft-lbf, momentum, Mach number and equivalent drop height from a projectile's mass and speed, or speed from energy.
Elastic Potential Energy Calculator
Find the energy stored in a spring (U = 1/2 k x^2), plus force, work between stretches, launch speed, spring constant and extension.
FPE Calculator - Foot-pounds of Energy
Foot-pounds of energy from grains and fps with joules, momentum, the 450240 shortcut check, and energy unit conversion.
Impact Energy Calculator
Energy of a dropped or moving object on impact, its equivalent fall height, and the average force from the stopping distance.
Potential Energy Calculator
Gravitational potential energy U = mgh and -GMm/r: joules, kWh, ft-lbf, calories, find mass or height, orbit energy and a chart.
Quiz: Potential Energy Calculator
Practise gravitational potential energy (U = m g h) with random problems at three levels, instant checking, worked solutions and a score streak.
Recoil Energy Calculator
Recoil velocity, recoil energy and momentum when a launcher fires a projectile, or the launcher mass needed for a recoil limit.
Angular Acceleration Calculator
Angular acceleration from a change in angular speed and time, from torque and moment of inertia, or from tangential acceleration and radius.
Angular Momentum Calculator
Angular momentum from L = I w or L = r m v sin theta, plus the new spin rate when the moment of inertia changes.
Angular Velocity Calculator
Convert angular velocity between rad/s, rpm, deg/s and Hz, or find it from angle and time, linear speed and radius, or period.
Centrifugal Force Calculator
Outward force on a mass in a rotating frame from rpm, rad/s, Hz or speed, with RCF in g and a note on why it is fictitious.
Centripetal Force Calculator
Inward force for circular motion from speed, rotation rate or period, plus ideal bank angle and vertical-loop normal forces.
Kinetic Energy of a Pendulum Calculator
KE, PE, speed and string tension at any angle from the release angle, with max speed at the bottom and a KE/PE chart.
Physical Pendulum Calculator
Period of a rod, disk, ring or custom body using I = I_cm + m d^2, with equivalent simple-pendulum length and a comparison chart.
Rotational Kinetic Energy Calculator
Rotational kinetic energy from I and spin rate, from a shape, mass and size, or for a rolling body (translational plus rotational).
Ballistic Coefficient Calculator
Ballistic coefficient from mass, diameter and drag coefficient, G1 style BC from sectional density and form factor, and speed retained over distance.
Car Jump Distance Calculator
Idealised ramp-jump physics: distance, air time, peak height, landing speed and angle, or the launch speed needed to clear a gap.
Displacement Calculator
Vector displacement versus distance from coordinates, a multi-leg path or constant acceleration, with direction angle and compass bearing.
Free Fall Calculator
Drop time, impact speed and fall height from any one known value, with planet gravity presets and speed and height charts.
Free Fall with Air Resistance Calculator
Exact tanh-solution fall under quadratic drag: speed, distance, terminal velocity, time to 95 percent and a vacuum comparison.
Friction Calculator
Static and kinetic friction on flat ground or a slope: force to start moving, will it slip, angle of repose, and mu from a pull or tilt test.
Inclined Plane Calculator
Ramp acceleration, time and speed at the bottom, push force up, work and efficiency, ramp length and grade, and angle of repose.
Quarter Mile Calculator
Estimate quarter mile ET and trap speed from weight and power, find the power for a target time, or use constant acceleration.
Rolling Resistance Calculator
Rolling resistance force, power, energy per km, a presets comparison table, coast-down distance and time, and rolling plus air drag.
SUVAT Calculator
Pick the three of s, u, v, a, t you know and it solves the other two, names the equation used and shows step-by-step working.
Sled Ride Calculator
Speed at the bottom of a slope, ride time and flat run-out distance with friction and optional air drag, plus a speed chart.
Trajectory Calculator
Projectile path with launch height and optional linear or quadratic drag, a position table at set intervals and a flight path chart.
Angle of Banking Calculator
Ideal bank angle, safe speed range with friction, required radius and railway cant, with a chart for each mode.
Car Crash Calculator
Educational two-vehicle collision physics (delta-v, energy lost, barrier-equivalent speed) and barrier impact deceleration.
Hooke's Law Calculator
Solve F = kx for force, spring constant or extension, combine up to four springs in series or parallel, and check the elastic limit.
Newton's Second Law Calculator
F = ma in any unit system (N, kN, lbf, dyne, kgf), with car, rocket and elevator presets, a net force mode and a weight mode.
Newton's Third Law Calculator
Equal and opposite force pairs for two pushing bodies, a collision with restitution, and rocket thrust, with velocity charts.
Stopping Distance Calculator
Reaction plus braking distance for any speed, road surface and grade, with a surface comparison table and a chart.
Tension Calculator
Rope tension for a hanging mass or elevator, an Atwood or table pulley, and two angled ropes, with diagrams and a safety factor.
kg to Newtons Calculator
Convert kg to newtons with W = mg, newtons back to kg and pounds to lbf, using Earth, Moon, Mars or any custom g.
Car Center of Mass Calculator
Locate a car's center of mass from axle weights and a lift test, with weight distribution, rollover threshold and a diagram.
Pounds per Square Inch Calculator
Calculate psi from force and area, convert psi to kPa, bar, atm and mmHg, and switch between gauge and absolute pressure.
Pressure Calculator
Solve pressure, force or area with P = F/A, or fluid pressure, density or depth with P = rho g h, in Pa, kPa, bar, atm, psi or torr.
Reduced Mass Calculator
Reduced mass of two bodies, a missing mass, orbital periods, and the hydrogen-like atom correction.
Weight on Other Planets Calculator
See what you would weigh on the Moon, Mars, Jupiter and the other planets, with a surface gravity table and comparison bars.
Power-to-Weight Ratio Calculator
Power-to-weight ratio in W/kg, hp per tonne and hp/lb, compare two vehicles, and estimate 0 to 60 mph and quarter mile times.
TNT Equivalent Calculator
Convert energy to TNT equivalent in kg, tons, kilotons and megatons using 4.184 MJ per kg, and back.
Work Calculator
Solve W = F d cos(theta) for work, force, distance or angle, plus work against friction, by gravity and by a spring.
Work and Power Calculator
Power from P = W/t and P = Fv, average vs instantaneous power, lifting with efficiency, and kWh energy cost.
Angular Displacement Calculator
Rotational kinematics theta = w0 t + 1/2 a t^2 (solve any), arc length s = r theta, and rad/deg/rev conversion.
Electricity
Ohm's Law Calculator
V = IR in all four modes: voltage, current, resistance, power
AC Wattage Calculator
Real, apparent, and reactive power via P = V·I·cos(φ)
Power Dissipation Calculator
P = VI = I²R = V²/R, plus junction temperature for transistors
Acceleration in the Electric Field Calculator
Find a = qE/m for an electron, proton, alpha or custom particle from a field or plate voltage, with speed, time and a relativistic check.
Drift Velocity Calculator
Electron drift velocity from current, wire diameter and material, transit time along a wire, or mobility v = mu E.
Energy Density of Fields Calculator
Electric and magnetic field energy density, total energy in a volume, or the field strength needed for a given energy density.
Lorentz Force Calculator
The Lorentz force F = q(E + v x B), its components, magnitude and angle, plus cyclotron radius and frequency.
EIRP Calculator - Effective Isotropic Radiated Power
EIRP in dBm, dBW and watts from transmit power, antenna gain and cable loss, ERP conversion, power density and link budget.
Signal-to-Noise Ratio Calculator
The general SNR tool: SNR in dB from power or RMS amplitudes, SNR to bits, and the thermal noise floor kTB.
Watt Converter
Convert power between W, kW, MW, GW, hp variants, BTU/h, kcal/h, ft lbf/s, dBm and dBW, with a full table.
Waves, Light, and Modern Physics
Speed of Light Calculator
Light travel time for any distance, m to light-years
Speed of Sound Calculator
v = √(γRT/M) in gases, plus reference speeds in water and solids
Speed of Sound in Solids Calculator
P-wave, S-wave, and bar-wave speeds from Young's modulus, Poisson's ratio, density
Mirror Equation Calculator
1/v + 1/u = 1/f for concave and convex spherical mirrors
Aperture Area Calculator
Light-collecting area from diameter or focal length and f-number
Electron Speed Calculator
Relativistic electron velocity, Lorentz factor, and de Broglie wavelength
Harmonic Wave Equation Calculator
Evaluates y = A sin(kx - wt + phi) with k, omega, wave speed and displacement at x and t, plus a waveform chart.
Diffraction Grating Calculator
Solve d sin theta = m lambda for the angle of each order, lines/mm from a measured angle, highest order, and resolving power.
Index of Refraction Calculator
Convert between n and light speed in a material, solve Snell's law with critical angle, or find an unknown n from two angles.
Lens Maker Equation Calculator
Focal length and power of a lens from n, R1, R2 and thickness, the radius a target focal length needs, or n from a measured lens.
Thin Lens Equation Calculator
Solve 1/f = 1/do + 1/di for image distance, magnification and image type, find f from distances, or the object distance for a wanted magnification.
Velocity Addition Calculator
Combine two velocities with the relativistic formula, compare with Galilean addition, see rapidity, and handle sideways motion.
Angular Frequency Calculator
Angular frequency from f, T or rpm, plus omega for springs, pendulums, LC circuits and 50/60/400 Hz mains, with sinusoid charts.
Rotational and Structural Mechanics
Mechanical Advantage Calculator
Lever, pulley, and inclined plane force multiplication
Mohr's Circle Calculator
Principal stresses, max shear stress, and principal plane angle
Flywheel Energy Storage Calculator
E = ½·k·m·r²·ω² for disk, ring, and sphere flywheels
Specific Heat Calculator
Q = mcΔT for calorimetry and thermal energy problems
Alfvén Velocity Calculator
Find the Alfven velocity from field and ion density, the Alfven Mach number, or the field needed for a target speed.
Shear Wave Velocity Calculator
Shear wave velocity from shear modulus and density, from Young's modulus and Poisson's ratio, or Vs30 with a site class.
Stiffness Matrix Calculator
Local and global stiffness matrix of a 2-node bar or truss element, or assemble and solve a 2-DOF spring system.
Linear Actuator Force Calculator
Size a linear actuator: required force for a vertical, inclined or sliding load, screw torque and efficiency, and motor thrust and power.
Piston Force Calculator
Hydraulic or pneumatic cylinder force from pressure and bore, extend and retract force, bore sizing, and speed from flow.
Polar Moment of Inertia Calculator
Area polar moment J of solid and hollow shafts and other sections in mm4 and in4, with torsion shear stress and twist angle.
Engine and Machining Engineering
BMEP Calculator
Brake Mean Effective Pressure from displacement, torque, and stroke type
Piston Speed Calculator
Mean piston speed and engine stress classification from stroke and RPM
Speeds and Feeds Calculator
Spindle RPM, feed rate, and metal removal rate for milling and turning
Darcy-Weisbach Calculator
Pipe head loss h_f = f·(L/D)·(V²/2g) and pressure drop
Ground Speed Calculator
Aircraft ground speed from true airspeed and wind vector
Arrow Speed Calculator
Real-world arrow speed from IBO rating using the ATA correction formula
What These Calculators Cover
Classical mechanics. The Force Calculator applies Newton’s second law, and the Acceleration and Kinematics Calculators handle every motion problem built from a, v, u, s, and t. The Projectile Motion Calculator extends kinematics to two dimensions, and the Work, Energy & Power and Kinetic Energy Calculators close the loop between force, motion, and energy.
Electricity. The Ohm’s Law Calculator covers DC resistive circuits in all four V/I/R/P modes, while the AC Wattage and Power Dissipation Calculators extend into AC power factor and thermal design for real components, including junction temperature limits for transistors and MOSFETs.
Waves, light, and modern physics. The Speed of Light and Speed of Sound Calculators cover the two reference velocities behind every wave problem, while the Speed of Sound in Solids Calculator extends to the P-wave and S-wave speeds used in non-destructive testing. The Mirror Equation and Aperture Area Calculators cover geometric optics, and the Electron Speed Calculator bridges into relativistic and quantum territory alongside the dedicated particle physics and quantum mechanics sections.
Rotational and structural mechanics. The Mechanical Advantage Calculator covers the three classic simple machines, the Mohr’s Circle Calculator finds principal stresses for combined loading, and the Flywheel Energy Storage Calculator applies rotational kinetic energy to real energy-storage hardware. The Specific Heat Calculator rounds out the group with basic calorimetry.
Engine and machining engineering. The BMEP and Piston Speed Calculators work together for internal combustion engine performance analysis, and the Speeds and Feeds Calculator covers CNC machining parameters. The Darcy-Weisbach Calculator handles pipe head loss (the same physics as the fluid dynamics section’s Moody chart calculator), and the Ground Speed and Arrow Speed Calculators apply vector addition and empirical ballistics correction to real-world aviation and archery problems.
Who Uses These Calculators
High school students use the classical mechanics and electricity calculators directly against their curriculum. Undergraduate engineering students use the structural (Mohr’s circle) and machining (speeds and feeds, BMEP) tools for mechanical engineering coursework. Automotive engineers and engine builders use the BMEP and piston speed calculators to classify engine stress levels. Electricians and electronics engineers use the Ohm’s law, AC wattage, and power dissipation calculators for cable sizing and thermal design. Pilots and flight students use the ground speed calculator for wind-triangle navigation problems, and archery and bowhunting enthusiasts use the arrow speed calculator to estimate real-world kinetic energy for game classification.
Frequently Asked Questions
What does SUVAT stand for?
s = displacement, u = initial velocity, v = final velocity, a = acceleration, t = time. The Kinematics Calculator uses all five equations of motion to solve for any two unknowns given three known values.
Does the projectile motion calculator account for air resistance?
No - the Projectile Motion Calculator uses the ideal model (no drag, constant g = 9.81 m/s²). This is the standard physics curriculum model. Real-world trajectories at high speeds or long ranges will differ.
What is the difference between work and power?
Work (joules) is total energy transferred: W = F × d. Power (watts) is the rate: P = W/t. A motor lifting 100 kg by 10 m does 9,810 J of work regardless of speed. If done in 10 s, power = 981 W; in 5 s, power = 1,962 W. Calculate both with the Work Energy Power Calculator.
Can the Ohm's law calculator handle AC circuits?
The Ohm's Law Calculator applies V = IR for DC resistive circuits. For AC circuits with reactance, impedance Z replaces R. For electronics circuit design, also see the Voltage Divider and Transformer Ratio calculators.
What is the difference between BMEP and piston speed for engine analysis?
BMEP (Brake Mean Effective Pressure) measures how effectively an engine uses its cylinder volume to produce torque, independent of engine size - it lets you compare a small turbocharged engine against a large naturally aspirated one on equal footing. Mean piston speed measures purely mechanical stress from the piston's reciprocating motion, largely independent of power output. A well-tuned engine needs both figures in a healthy range: high BMEP with excessive piston speed risks mechanical failure, while low BMEP at safe piston speed means the engine is underutilized. Use the BMEP and Piston Speed Calculators together for a full picture.
Why does Mohr's circle work for stress transformation?
Mohr's circle is a graphical solution to the stress transformation equations, exploiting the fact that normal stress σ(θ) and shear stress τ(θ) at any rotated angle trace out a circle when plotted against each other, centered at the average normal stress (σx+σy)/2 with radius equal to the maximum shear stress. This lets you read off the principal stresses (where the circle crosses the σ-axis, τ=0) and the maximum shear stress (the circle's radius) without re-deriving the transformation equations for every angle. The Mohr's Circle Calculator computes these directly from σx, σy, and τxy.