Calculate blast yield, energy released, or TNT energy per ton from the other two values in joules, kilojoules, megatons, or kilotons.
Customize This Calculator
Build your own version. Describe what you want changed, added, or compared.
Blast Yield Formula
The blast yield calculation compares total energy released to the energy released by one ton of TNT. The calculator uses tons of TNT equivalent as the base yield unit, then converts the result to kilotons or megatons.
- Y = blast yield in tons of TNT equivalent
- E = total energy released, in joules
- E_T = energy released by one ton of TNT, in joules per ton
To calculate total energy released when you know the blast yield:
To calculate the energy value being used for one ton of TNT:
The calculator accepts any two values and solves for the missing one:
- Energy Released: calculated from blast yield multiplied by energy per ton of TNT.
- Energy Released by One Ton of TNT: calculated by dividing total energy by TNT-equivalent tons.
- Blast Yield: calculated by dividing total energy by energy per ton of TNT, then converting tons to kilotons or megatons.
Common TNT Energy and Yield Conversions
A commonly used reference value for TNT equivalent is 4.184 gigajoules per ton of TNT.
| TNT equivalent unit | Tons of TNT | Energy using 4.184 GJ/ton |
|---|---|---|
| 1 ton | 1 ton | 4.184 GJ |
| 1 kiloton | 1,000 tons | 4.184 TJ |
| 1 megaton | 1,000,000 tons | 4.184 PJ |
| Unit | Equivalent | Used for |
|---|---|---|
| 1 kJ | 1,000 J | Small energy inputs |
| 1 MJ | 1,000,000 J | Medium energy inputs |
| 1 GJ | 1,000,000,000 J | TNT energy per ton and large releases |
| 1 kt | 1,000 tons of TNT | Blast yield output |
| 1 Mt | 1,000,000 tons of TNT | Large blast yield output |
Example Calculations
Example 1: Calculate blast yield from energy released
You have an energy release of 8,368 GJ and use 4.184 GJ as the energy released by one ton of TNT.
Convert tons to kilotons:
The blast yield is 2 kt.
Example 2: Calculate energy released from blast yield
You have a blast yield of 0.5 kt and use 4.184 GJ per ton of TNT.
First convert kilotons to tons:
Then calculate total energy:
The energy released is 2,092 GJ.
FAQ
What value should I use for energy released by one ton of TNT?
A common TNT equivalent value is 4.184 GJ per ton of TNT. In joules, that is 4,184,000,000 J. The calculator lets you enter a different value if your source or problem statement uses another TNT reference value.
What is the difference between kilotons and megatons?
A kiloton is 1,000 tons of TNT equivalent. A megaton is 1,000,000 tons of TNT equivalent. That means 1 megaton equals 1,000 kilotons.
Why do I need to enter exactly two values?
The relationship has three variables: total energy, energy per ton of TNT, and blast yield. If you provide any two of them, the third can be calculated. If you enter all three, there is no missing value to solve for. If you enter only one, there is not enough information to calculate a result.
