Free online fuel cost calculator

How to use

1. Toggle MPG or L/100km to match how your car’s efficiency is rated.
2. Enter the trip distance in miles or kilometers.
3. Enter your car’s fuel efficiency (MPG or L/100km).
4. Enter the current gas or diesel price per gallon or liter.
5. Read total cost, fuel used, and cost per mile or per kilometer.

Formulas

MPG mode:

fuel used (gal) = distance (mi) ÷ MPG
total cost      = fuel used × price per gallon
cost per mile   = price per gallon ÷ MPG

L/100km mode:

fuel used (L) = (distance (km) ÷ 100) × L/100km
total cost    = fuel used × price per liter
cost per km   = (L/100km ÷ 100) × price per liter

Worked examples

US road trip: 300 miles at 30 MPG, gas at $3.50/gallon:

fuel used  = 300 ÷ 30      = 10 gallons
total cost = 10 × 3.50     = $35.00
cost/mile  = 3.50 ÷ 30     = $0.12

European drive: 500 km at 7 L/100km, fuel at €1.75/liter:

fuel used  = (500 ÷ 100) × 7 = 35 liters
total cost = 35 × 1.75       = €61.25
cost/km    = (7 ÷ 100) × 1.75 = €0.1225

Notes

• Actual fuel economy is usually 10–20% lower than EPA/WLTP ratings in real-world driving.
• Highway driving is more efficient than city driving for most non-hybrid vehicles.
• For electric vehicles, substitute kWh/100mi or mi/kWh and price per kWh for a comparable cost estimate.