Calculate burn time, total fuel, or burn rate from any two values with kg, lb, ton, seconds, minutes, and hours in any unit system.
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Burn Time Formula
The burn time calculator uses the relationship between total fuel, burn rate, and time. Enter any two values to solve for the missing one.
T = F / R
- T = burn time
- F = total fuel
- R = burn rate
To calculate total fuel instead of burn time, the formula is rearranged:
F = R * T
To calculate burn rate, the formula is:
R = F / T
The calculator converts all inputs to base units before calculating: kilograms for fuel, kilograms per second for burn rate, and seconds for time. It then converts the result back to the unit you selected.
- Find burn time: use total fuel and burn rate to calculate how long the fuel lasts.
- Find total fuel: use burn rate and burn time to calculate how much fuel is required.
- Find burn rate: use total fuel and burn time to calculate fuel consumed per unit of time.
Fuel and Burn Rate Unit Conversions
These are the conversion factors used to keep the calculation consistent across different unit choices.
| Fuel unit | Equivalent in kilograms |
|---|---|
| 1 kilogram | 1 kg |
| 1 pound | 0.453592 kg |
| 1 ton | 1000 kg |
| Burn rate unit | Equivalent in kg/s | Common use |
|---|---|---|
| 1 kg/s | 1 kg/s | Direct metric burn rate |
| 1 lb/s | 0.453592 kg/s | Imperial fuel flow |
| 1 ton/h | 0.277778 kg/s | Large hourly consumption rates |
Example Burn Time Calculations
Example 1: Calculate burn time
You have 50 kg of fuel and a burn rate of 2 kg/s.
T = F / R
T = 50 / 2 = 25 s
The burn time is 25 seconds.
Example 2: Calculate total fuel needed
You need to burn fuel for 30 minutes at a rate of 0.5 kg/s.
First convert 30 minutes to seconds:
30 min * 60 = 1800 s
Then calculate total fuel:
F = R * T
F = 0.5 * 1800 = 900 kg
The required fuel is 900 kg.
Burn Time Calculator FAQ
What does burn time mean?
Burn time is the amount of time a given quantity of fuel will last at a specific burn rate. If the burn rate stays constant, burn time is found by dividing total fuel by burn rate.
Why do the units matter?
The units must match before the formula is applied. For example, if fuel is in kilograms and burn rate is in kilograms per second, the burn time result is in seconds. If you use pounds, tons, minutes, or hours, the calculator converts the values first so the formula still works correctly.
Can burn rate change during real use?
Yes. This calculator assumes a constant burn rate. In real systems, burn rate may change with pressure, temperature, throttle setting, fuel quality, or operating conditions. If the burn rate changes over time, the result should be treated as an estimate.