This gallons per hour calculator estimates an engine’s fuel burn rate from its horsepower, handy for boats and generators. Enter the horsepower above for the GPH.
Formula (gasoline estimate)
GPH ≈ HP × 0.5 ÷ 6.1
It assumes a brake-specific fuel consumption near 0.5 lb/hp·hr and 6.1 lb per gallon of gasoline. Diesel burns less.
Example
200 HP gasoline: GPH ≈ 200 × 0.5 ÷ 6.1 = 16.4 GPH.
Related calculators
Frequently Asked Questions
How do I calculate gallons per hour?
Multiply horsepower by about 0.5 and divide by 6.1 for a gasoline engine at full load.
How much fuel does a 200 HP engine burn?
Roughly 16 gallons per hour of gasoline at wide-open throttle; cruising uses much less.
Does diesel use less fuel per hour?
Yes. Diesel’s lower fuel consumption and higher energy density mean fewer gallons per hour than gasoline.