Gas Mileage (MPG) Calculator

Compute miles per gallon from distance and gallons used. Also returns L/100km.

Result

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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

Why does my displayed MPG differ from manual calculation?+

Onboard computers estimate based on injector pulses and air-flow sensors, often optimistic by 2-5%. Tank-to-tank manual is more accurate.

How do I convert MPG to L/100km?+

L/100km = 235.215 / MPG (approximately). Or convert through km and L as the calculator shows.

Why is highway MPG higher than city?+

Cruising at steady speed with momentum is more efficient than stop-and-go. Aerodynamic drag rises sharply above 60 mph though.

How can I improve my MPG?+

Properly inflated tires (+3%), smooth driving (+10-20%), reduce roof-rack drag, fix dirty air filter. The mpg-improvement-tips-calc estimates savings.

Is the EPA MPG accurate?+

Within 5-10% for most drivers. Real-world MPG depends heavily on terrain, traffic, AC use, and driving style.