MPG Calculator
Work out your real-world gas mileage from a fill-up — by trip distance or odometer readings — plus cost per mile and metric conversions.
For an accurate number, fill the tank completely both times — the gallons it takes to refill is exactly what you burned since the last full tank.
How to calculate gas mileage
The gold-standard method is the full-tank method: fill the tank, reset your trip odometer (or note the mileage), drive normally, then fill up again. Your MPG is simply miles driven ÷ gallons it took to refill. Measured this way, the number reflects reality — unlike the in-dash average, which is often a little optimistic.
Expect real-world MPG to run below the EPA sticker, especially with short trips, city driving, roof racks, spirited canyon runs, or a heavy right foot. Tracking a few tanks in a row is the best way to spot a change — a sudden drop can be an early sign of anything from low tire pressure to a lazy oxygen sensor.
Planning a longer trip with the number you just measured? Feed it into the road trip fuel cost calculator to budget the drive — and record the trip itself with GPS in Ryvve.
Frequently Asked Questions
Use the full-tank method: fill your tank completely, note the odometer (or reset the trip meter), drive normally, then fill up again. Divide the miles you drove by the gallons it took to refill — that's your true MPG. This calculator does the division and adds cost per mile and metric conversions.
Every Drive, Logged Automatically
Ryvve records your drives with GPS — route, distance, and stats — so your real mileage log builds itself. Free on iOS and Android, with CarPlay.
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