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Fuel Pump Sizing Calculator
Size fuel pump flow for your horsepower goal
Fuel pump sizing calculates the fuel flow a pump must deliver at rail pressure to feed a given horsepower.
Formula: Pump flow (gph) = HP × BSFC ÷ fuel density — at rail pressure: base pressure + boost
What this number means
This calculates the fuel volume your engine needs at full power, in litres or gallons per hour, from horsepower and fuel type. It sizes for flow at pressure — the condition a pump actually struggles with — not free-flow ratings.
What to change next
Pick a pump rated above the result at your system's operating pressure, with margin for boost-referenced pressure if boosted. If the current pump is marginal, fix supply before tuning — no tune survives a pump that cannot keep up.
Worked example
600 hp on gasoline at 0.50 BSFC needs ≈ 300 lb/hr of fuel, which is ≈ 49 gal/hr (≈ 186 L/hr) at pressure, before safety margin.