MPG Calculator

What is MPG?

MPG means miles per gallon. It measures how many miles your vehicle travels for each gallon of fuel. This miles per gallon calculator uses the distance driven and fuel used to calculate your fuel economy.

The calculator also shows L/100 km and fuel cost per mile. L/100 km expresses fuel use in a different way: lower fuel use for a given distance means a lower L/100 km value. Cost per mile estimates fuel spending for each mile driven. It does not include maintenance, insurance, registration or depreciation.

Why MPG matters

Fuel economy connects your driving to your budget. If you know your MPG and gas price, you can estimate how fuel spending changes when you drive farther, change vehicles or adjust your routine. For a household, that can help with a vehicle purchase or a monthly budget. For a business, it can inform delivery pricing, route choices and whether a vehicle is earning enough to justify its fuel costs.

A single reading is most useful as a starting point. Compare it with your own past trips under similar driving conditions. For a vehicle purchase, compare the vehicles using the same kind of trip and your expected fuel price, rather than relying only on a general estimate.

How to use this MPG calculator

1. Enter the miles driven during the period you want to measure.
2. Enter the gallons used over that same period. Use fuel consumed, not just the amount you happened to buy if your fuel tank level changed.
3. Enter the gas price per gallon to estimate fuel cost per mile.
4. Review MPG, L/100 km and cost per mile. Use matching distance and fuel records when comparing trips or vehicles.

MPG calculator example

How to read your MPG result

A higher MPG means you travel farther on each gallon. A lower L/100 km means you use less fuel over a given distance. The cost per mile helps translate fuel use into dollars, based on the gas price you entered.

Treat the result as an estimate for the miles and gallons you entered. Driving conditions, traffic, cargo and vehicle maintenance can affect fuel use. If you compare readings, use consistent records and note when your driving conditions changed.

How to improve your MPG

1. 01

   Check tire pressure and routine maintenance

   Follow your vehicle’s recommended tire pressure and maintenance schedule. Underinflated tires or overdue service can affect fuel use.

2. 02

   Reduce avoidable weight and trips

   Remove cargo you do not need and combine errands when practical. Fewer unnecessary miles mean less fuel used.

3. 03

   Drive smoothly

   Avoid rapid starts and hard braking when traffic allows. Steadier driving can help limit wasted fuel.

4. 04

   Track results before making a change

   Record miles and gallons across comparable trips. If you manage a business fleet, compare fuel cost per mile by vehicle or route before changing assignments or pricing.

Common MPG calculator mistakes

• Mixing different time periods

  Miles and gallons must cover the same driving period. Otherwise, the MPG result will not describe that trip or period accurately.

• Using fuel purchased instead of fuel used

  A purchase may not match the fuel consumed if the tank was not at the same level at the start and end of your measurement.

• Comparing unlike trips

  Traffic, route, cargo and driving style can change fuel use. Compare similar trips where possible, or treat differences as context rather than proof that a vehicle has changed.

• Treating fuel cost per mile as total vehicle cost

  This result covers fuel only. Add other vehicle expenses separately when you are setting a business rate or comparing ownership costs.

The MPG formula

Key terms

MPG

Miles per gallon: the miles a vehicle travels for each gallon of fuel.

L/100 km

Liters per 100 kilometers, a fuel-use measure that expresses how much fuel a vehicle uses over a distance.

Cost per mile

Estimated fuel spending for each mile driven, based on the fuel price entered.