⛽ Gas Mileage Calculator
Calculate fuel efficiency with vehicle presets📊 Mileage Result
Gas Mileage Calculator — Find Your Vehicle’s Actual MPG
Want to know your car’s real fuel efficiency instead of relying on the window-sticker EPA estimate? Our Gas Mileage Calculator works out your actual miles-per-gallon (MPG) using just two numbers: the miles you drove and the gallons of gas it took to refill your tank.
How It Works
MPG = Miles Driven ÷ Gallons of Gas Used
For example, if you drove 300 miles and it took 10 gallons to fill the tank back up, your gas mileage is 300 ÷ 10 = 30 MPG.
Real-World MPG vs. EPA-Estimated MPG
The MPG figure on a car’s window sticker is an EPA estimate measured under standardized lab conditions. Your real-world MPG is usually 10-20% lower because of city traffic, air conditioning, cold starts, terrain, and driving style — which is why calculating your actual mileage matters before budgeting for a road trip.
| Factor | Effect on MPG |
|---|---|
| Stop-and-go city driving | Reduces MPG by 15-25% |
| Highway cruising at steady speed | Closest to EPA-rated MPG |
| Air conditioning | Reduces MPG by 5-10% |
| Under-inflated tyres | Reduces MPG by 3-5% |
| Heavy load / cargo | Reduces MPG by 2-8% |
Once you know your real MPG, use it in our Trip Fuel Cost Calculator to get an accurate gas budget for your next road trip.
Tip for the Most Accurate Reading
Calculate MPG over a full tank-to-tank cycle: fill up completely, reset your trip odometer, drive normally, then fill up completely again. Divide the miles on your trip odometer by the gallons needed to refill.
Frequently Asked Questions
How do I calculate my car’s gas mileage?
Fill your tank completely, reset your trip odometer, drive as normal, then fill up completely again. Divide the miles driven (from the trip odometer) by the gallons used to refill — that’s your real MPG.
Why is my actual MPG lower than the EPA estimate?
EPA ratings come from standardized lab testing. Real driving involves traffic, AC use, hills, and varying speeds, which typically reduce MPG by 10-20% compared to the sticker figure.
What’s a good MPG for a car?
Compact and midsize gas cars typically get 28-35 MPG on the highway and 20-28 MPG in the city; hybrids can exceed 45-55 MPG combined; larger SUVs and trucks often average 15-22 MPG.
Does this calculator work for trucks and SUVs?
Yes — the miles ÷ gallons formula applies to any gasoline vehicle, including trucks, SUVs, and motorcycles.