Gas Mileage (MPG) Calculator
Compute miles per gallon from distance and gallons used. Also returns L/100km.
Result
Fuel economy
29.17 MPG
8.06 L/100km · 12.40 km/L.
- Miles350
- Gallons12
- MPG29.17
- L/100km8.06
- km/L12.40
Step-by-step
- MPG = miles / gallons = 350 / 12 = 29.17.
- Convert to metric: 350 mi × 1.6093 = 563.3 km; 12 gal × 3.7854 = 45.42 L.
- L/100km = (45.42 / 563.3) × 100 = 8.06.
How to use this calculator
- Fill up your tank, reset trip odometer.
- Drive until next fill-up.
- Enter the miles driven and gallons used to refill.
About this calculator
MPG is the standard US fuel-economy unit. Higher is better. Modern cars average 30-35 MPG combined; hybrids 45-55; large pickups 18-22. Outside the US, L/100km is more common — and the math is inverse: lower L/100km is better.
Frequently asked
Onboard computers estimate based on injector pulses and air-flow sensors, often optimistic by 2-5%. Tank-to-tank manual is more accurate.
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