Fuel Mileage (MPG) Calculator
Calculate your vehicle's fuel efficiency and driving costs.
Calculation Summary
Total Distance:
0 miles
Fuel Economy:
0 MPG
Cost per Mile:
$0.00
Total Trip Cost:
$0.00
How to Calculate Fuel Mileage
Understanding your vehicle's fuel economy is essential for budgeting and monitoring your car's mechanical health. Fuel mileage is most commonly expressed in Miles Per Gallon (MPG) in the United States or Liters per 100 Kilometers (L/100km) in many other regions.
The Step-by-Step Manual Method
You don't need fancy onboard computers to find your true MPG. Follow these steps the next time you visit the gas station:
- Fill Your Tank: Fill your tank until the pump clicks off. Record your current odometer reading (this is your Start Odometer).
- Drive Normally: Drive your vehicle as you usually would until you need more fuel.
- Refill and Record: Go back to the pump. Note your new odometer reading (End Odometer) and exactly how many gallons it took to fill the tank back up.
- The Formula: Subtract the Start Odometer from the End Odometer to get your total distance. Divide that distance by the number of gallons used.
The MPG Formula
(End Miles – Start Miles) / Gallons = MPG
Example Calculation
Suppose your odometer read 20,000 miles when you filled up. Next time you fill up, the odometer reads 20,300 miles, and the pump says you added 10 gallons of fuel.
- Distance: 20,300 – 20,000 = 300 miles.
- MPG: 300 / 10 = 30 MPG.
- Fuel Cost: If gas was $3.50/gallon, you spent $35.00.
- Cost Per Mile: $35.00 / 300 miles = $0.116 per mile.
Why Monitoring Fuel Mileage Matters
A sudden drop in fuel economy can be an early warning sign of mechanical issues, such as low tire pressure, a clogged air filter, or failing oxygen sensors. By tracking your mileage consistently, you can catch maintenance needs before they become expensive repairs.