Gas Mileage Calculator

Calculate your vehicle fuel efficiency in MPG or L/100km and estimate fuel costs for trips.

Unit system

Result

Fill in the fields above, then press Calculate.

A gas mileage calculator measures your vehicle's fuel efficiency in MPG or L/100km so you can track consumption and compare costs.

Select your unit system, enter the distance traveled, fuel used, and fuel price. The calculator computes fuel efficiency (MPG or L/100km) and cost per distance unit.

Examples

Road trip efficiency

300 miles on 12 gallons at $3.50/gal: MPG = 25.0, Total cost = $42.00, Cost/mile = $0.14.

Metric example

500 km on 40 liters: 12.5 km/L = 8.0 L/100km. This equals about 29.4 MPG.

Frequently Asked Questions

What is a good MPG?
The average new car in the US gets about 25-30 MPG combined. Hybrids typically achieve 40-60 MPG, while EVs equivalent can exceed 100 MPGe.
How do MPG and L/100km relate?
They are inversely related: 235.214 / MPG = L/100km. A car getting 30 MPG uses about 7.8 L/100km. Lower L/100km is better, while higher MPG is better.
Related Calculators
Fuel Cost Calculator
Mileage Calculator
EV Charging Cost Calculator
Speed Calculator

Quick Tips

  • •Fill your tank completely, reset your trip odometer, and refill completely for the most accurate measurement.
  • •MPG varies with driving conditions: highway typically yields 20-30% better MPG than city driving.
  • •Tire pressure, speed, and AC usage significantly affect fuel efficiency.