BSFC Calculator
Measure brake specific fuel consumption from fuel flow and engine power, or work backwards to find the fuel flow requirement.
Choose imperial or metric units so the calculator matches the numbers you already use in your shop or workbook.
Result
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Run the calculation to see the BSFC result.
Quick Answer
BSFC is fuel flow divided by power, so lower values mean the engine makes more power for each unit of fuel burned.
How to Use It
- Choose imperial or metric units.
- Enter fuel flow and engine power.
- Optionally switch to fuel-flow mode and enter a target BSFC.
- Click Calculate to see the output.
Formula
BSFC = fuel flow / engine power
Fuel flow needed = target BSFC x engine power
Worked Examples
Example 1: 24 lb/h divided by 180 hp gives 0.133 lb/(hp*hr).
Example 2: 8000 g/h divided by 100 kW gives 80 g/kWh.
Example 3: 0.50 lb/(hp*hr) at 200 hp needs 100 lb/h of fuel flow.
How to Interpret Your Results
| Output | Meaning | Action |
|---|---|---|
| Lower BSFC | Better fuel efficiency for the power produced. | Compare engine tunes or operating points. |
| Higher BSFC | More fuel is needed for each unit of power. | Check load, tuning, and operating range. |
| Fuel flow needed | Fuel required to hit the chosen target BSFC. | Verify supply, injector sizing, and safety margin. |
Frequently Asked Questions
Usually yes, because it means the engine is making more power for each unit of fuel. That said, compare BSFC at similar load and speed points.
Because the units themselves are different. The calculator keeps the formula the same but matches each system's standard BSFC output.
Yes. BSFC is useful for many engine types as long as you keep the fuel flow and power units consistent.
Related Calculators
References
- OmniCalculator reference page
- BSFC is computed as fuel flow divided by brake power in the selected unit system.
- Last reviewed: March 2026.