TNT Equivalent Calculator
Express any amount of energy in tons of TNT, or turn tons of TNT back into joules, kilowatt-hours and kilocalories.
💥 What is TNT Equivalent?
TNT equivalent is a convention for expressing a quantity of energy as the mass of trinitrotoluene (TNT) that would release the same energy. By definition, one ton of TNT equals 4.184 gigajoules, so one kilogram equals 4.184 megajoules. The value is the same as one gigacalorie per ton and one thousand kilocalories per kilogram, which is why the conversion factor looks so tidy in calories. The kiloton (4.184 terajoules) and megaton (4.184 petajoules) are simply multiples of that ton. Because the figure is fixed, TNT equivalent is purely a unit of energy, in the same family as the joule, the kilowatt-hour and the kilocalorie.
The unit is used when a very large energy needs a familiar yardstick. Earth scientists express the energy of earthquakes, volcanic eruptions and meteor impacts in tons, kilotons or megatons, astronomers use it for asteroid and comet kinetic energy, and energy writers use it to compare fuels, batteries and accidents. Historical events are also described this way: the Hiroshima bomb of 1945 is commonly quoted at about 15 kilotons, and this calculator uses that value only as a size comparison for an amount of energy. Where chemistry matters, the real energy of TNT is close to, but not exactly, 4.184 MJ per kg, which is why the figure is a convention.
Several misunderstandings are worth clearing up. TNT equivalent says how much energy is involved, not what that energy does. The same energy released slowly, spread across a large area, or deep underground has very different effects from the same energy released at once on a surface, so the number is not a measure of damage. Energy is also not power: a megaton is a quantity, and the time over which it is released is a separate question. Finally, the term does not mean any real TNT is present. A battery, a fuel tank or a moving rock can all be expressed in tons of TNT equivalent without any explosive involved.
This calculator has three modes. Energy to TNT converts joules, kilojoules, megajoules, gigajoules, terajoules, petajoules, kilowatt-hours or kilocalories into kilograms, tons, kilotons and megatons. TNT to energy goes the other way. Falling rock expresses the kinetic energy of a sphere of a given diameter, density and speed in TNT units, with a chart against diameter. Each mode shows how your value compares with common benchmark amounts.
📐 Formula
📖 How to Use This Calculator
Steps
💡 Example Calculations
Example 1 — One Gigajoule in TNT
1 GJ of energy
Example 2 — The Energy of 15 Kilotons
62.76 TJ of energy
Example 3 — One Kiloton Back to Energy
1 kiloton of TNT equivalent
Example 4 — A 20 m Rock at 19 km/s (Unit Comparison)
Sphere, d = 20 m, ρ = 3000 kg/m³, v = 19 km/s
Example 5 — A 1 m Rock at 15 km/s
Sphere, d = 1 m, ρ = 3000 kg/m³, v = 15 km/s
❓ Frequently Asked Questions
🔗 Related Calculators
How many joules are in a ton of TNT?
One ton of TNT is defined as 4.184 gigajoules, or 4.184 x 10^9 J. This is the conventional figure used in energy comparisons, equal to one gigacalorie, and it makes 1 kg of TNT equal to 4.184 MJ.
How many joules are in a kiloton of TNT?
One kiloton is 4.184 x 10^12 J, which is 4.184 terajoules. It is 1000 tons of TNT. A megaton is 4.184 x 10^15 J, or 4.184 petajoules.
How do I convert joules to TNT equivalent?
Divide the energy in joules by 4.184 x 10^6 to get kilograms of TNT, or by 4.184 x 10^9 to get tons. For example 1 GJ is 239.0 kg of TNT, or 0.239 tons.
How do I convert kWh to tons of TNT?
Multiply kilowatt-hours by 3.6 million to get joules, then divide by 4.184 x 10^9. One kWh is about 0.86 kg of TNT equivalent, since 3.6 MJ divided by 4.184 MJ per kg is 0.860.
What is the TNT equivalent of a kilocalorie?
One kilocalorie is 4184 J, which is exactly 1 gram of TNT on the conventional scale. A gigacalorie is 1 ton of TNT, which is why the ton of TNT is defined as 4.184 GJ.
How many 15 kiloton units is a megaton?
A megaton is about 67 times a 15 kiloton yield, since 1000 kt divided by 15 kt is 66.7. The 15 kt figure is a commonly quoted approximate yield and is used here only as a size comparison for an amount of energy.
How do you find the TNT equivalent of an asteroid?
Compute the kinetic energy, half x mass x speed squared, and divide by 4.184 x 10^9 J per ton. A 20 m rock at 3000 kg/m3 and 19 km/s carries 2.27 x 10^15 J, or about 542 kt of TNT equivalent.
Does TNT equivalent tell me how damaging an event is?
No. It is a measure of total energy only. Effects depend on how and where the energy is released, the medium, the altitude and many other factors, so this calculator is a unit converter and not a damage estimator.
Why is the ton of TNT defined as 4.184 GJ?
It is a convention: 4.184 MJ per kg is 1000 kilocalories per kg. It is close to the energy released when TNT detonates, but measured values vary a little, so the definition fixes a single exact number for comparisons.
Is a ton of TNT a metric ton?
In the standard convention the ton is a metric ton of 1000 kg, so 1 ton is 4.184 GJ. The energy is a fixed definition, which is why this calculator uses 1000 kg per ton for the TNT mass.