Gas Mileage Calculator

1. To calculate your actual MPG: Next time you fill up, reset your trip odometer to zero. Drive normally until your tank is low, then fill up again. Record the miles driven and gallons pumped. Enter those two numbers into the "Calculate MPG" mode above.
2. To estimate annual fuel costs: Switch to "Estimate Cost" mode. Enter your vehicle's MPG rating (find it at fueleconomy.gov), your annual mileage estimate, and your local gas price. The calculator shows annual cost, monthly cost, and cost per mile.
3. Use the comparison table to see how different MPG ratings translate to annual fuel spending at a typical gas price and mileage.

Calculating MPG from a fill-up:

MPG = Miles driven / Gallons used

Example: 350 miles driven, 11.5 gallons pumped
MPG = 350 / 11.5 = 30.4 MPG

Converting between systems:

L/100km = 235.215 / MPG
km/L    = MPG × 0.425144

Example: 30 MPG
L/100km = 235.215 / 30 = 7.84 L/100km
km/L    = 30 × 0.425 = 12.75 km/L

Annual fuel cost:

Annual cost = (Annual miles / MPG) × Gas price per gallon

Example: 15,000 miles/year, 30 MPG, $3.50/gal
Cost = (15,000 / 30) × $3.50 = 500 × $3.50 = $1,750/year