Lift Force and Lift Coefficient Calculator
Find aerodynamic lift force L = ½ρv²C_LA, the force that holds an aircraft wing or hydrofoil up against gravity.
✈️ What is the Lift Force and Lift Coefficient Calculator?
This lift force calculator finds L=½ρv²C_LA, the aerodynamic force that acts perpendicular to the oncoming airflow and holds an aircraft wing, hydrofoil, or sail up against gravity or a side load. Enter the fluid density, velocity, lift coefficient, and wing planform area, and it returns the lift force along with the underlying dynamic pressure.
L = ½ρv²C_LA combines dynamic pressure (½ρv²) with the wing's lift coefficient C_L and planform area A, the standard formula used across aerodynamics and hydrodynamics, and it has exactly the same structural form as the drag force equation.
This formula is used to size wings for a target takeoff speed, to check whether a given airspeed and angle of attack produce enough lift to sustain level flight, to estimate the downforce generated by a race car's inverted wing, and to analyze the lift produced by hydrofoils, propeller blades, and sailboat keels.
Because lift scales with velocity squared, doubling airspeed quadruples the lift force for a fixed C_L and area, which is exactly why aircraft rely on high-lift devices like flaps and slats at low takeoff and landing speeds but need only a small angle of attack at cruise.
This calculator is useful for aerospace and mechanical engineering students studying aerodynamic lift, flight instructors explaining stall speed, and anyone estimating the lift or downforce produced by a wing, hydrofoil, or spoiler.
📐 Formula
📖 How to Use This Calculator
Steps
💡 Example Calculations
Example 1 - Small aircraft in level cruise
Example 2 - Airliner in high-lift takeoff configuration
Example 3 - RC glider wing
❓ Frequently Asked Questions
🔗 Related Calculators
What is lift force?
Lift force is the component of aerodynamic force acting perpendicular to the oncoming flow direction, generated as air (or another fluid) moves over a wing or airfoil. It is the force that counteracts an aircraft's weight and keeps it airborne.
What is the formula for lift force?
L = ½ρv²C_LA, where ρ is fluid density, v is the airspeed relative to the fluid, C_L is the dimensionless lift coefficient (capturing airfoil shape and angle of attack), and A is the wing planform area.
What is the lift coefficient?
The lift coefficient, C_L, is a dimensionless number that captures how an airfoil's shape and angle of attack affect lift, independent of its size or speed. A typical cruise C_L is around 0.3 to 0.5, while a wing near its maximum angle of attack before stall can reach C_L around 1.5 to 2.0 with flaps deployed.
Why does lift force increase with the square of velocity?
Because lift force depends on dynamic pressure (½ρv²), which itself scales with velocity squared, doubling airspeed quadruples the lift force. This is why aircraft need a high angle of attack and full flaps at low takeoff speed, but only a small angle of attack at high cruise speed.
What is 'wing planform area' in the lift equation?
Wing planform area is the projected area of the wing as seen from directly above, essentially its top-down silhouette including the portion that passes through the fuselage. It is not the total skin area of the top and bottom wing surfaces combined.
What are typical lift coefficients for aircraft wings?
A typical cruise configuration sits around C_L≈0.3-0.5, a wing near maximum lift with flaps and slats extended for takeoff or landing can reach C_L≈1.5-2.5, and a symmetric airfoil at zero angle of attack produces close to C_L≈0.
How is lift force related to dynamic pressure?
Dynamic pressure, ½ρv², represents the kinetic energy per unit volume of the moving fluid relative to the wing. Lift force is simply this dynamic pressure multiplied by the lift coefficient and wing area, the same dynamic pressure term also appears in Bernoulli's equation and the drag equation.
Can the lift coefficient be negative?
Yes, a negative C_L produces downforce instead of lift, which is exactly how an inverted wing on a race car or the tailplane of many aircraft is designed to push down rather than up, improving traction or pitch stability.
How does stall relate to the lift coefficient?
As angle of attack increases, C_L rises roughly linearly until it reaches a maximum value (C_L,max), beyond which the airflow separates from the wing's upper surface and lift drops sharply. This sudden loss of lift is called a stall, and it happens at a specific angle of attack regardless of airspeed.
Is this the same lift equation used for both air and water?
Yes, the lift equation L=½ρv²C_LA applies to any fluid, only the density ρ (and the lift coefficient's dependence on Reynolds number and shape) changes between air, water, or any other fluid, which is why it also describes hydrofoils and propeller blades.