Enter distance
Add the miles or kilometres travelled during the trip.
Fuel economy calculator
MPG Calculator
Calculate gas mileage, fuel consumption, trip fuel use, and estimated fuel cost with flexible distance and volume units.
Multiple unit options
Instant results
Fuel cost estimate
Calculation setup
Enter trip and fuel details
Enter the distance travelled and fuel used. Choose the units that match your odometer and fuel receipt.
per selected fuel unit
Core formulas
MPG = distance in miles ÷ fuel used in gallons. L/100 km = litres used ÷ kilometres travelled × 100.
Calculation result
Your fuel economy results
Enter your trip details
Calculate US MPG, imperial MPG, km/L, L/100 km, and optional fuel cost.
Simple process
How the MPG calculator works
The calculator standardizes your distance and fuel units, then calculates comparable fuel economy results.
Add fuel used
Enter US gallons, imperial gallons, or litres consumed.
Apply the formula
The tool converts both inputs to standard units and divides distance by fuel.
Review the result
See US MPG, imperial MPG, km/L, L/100 km, and estimated trip cost.
What is an MPG calculator?
An MPG calculator measures how far a vehicle travels for each gallon of fuel used. It helps drivers check real-world gas mileage, compare vehicles, monitor efficiency, and estimate the fuel cost of a completed trip.
The MPG formula
Divide distance travelled by fuel used: MPG = miles ÷ gallons. For an accurate result, reset the trip odometer when filling the tank, drive normally, refill the tank, and use the amount shown on the second fuel receipt.
Understanding MPG and L/100 km
Higher MPG and km/L values indicate better fuel economy because the vehicle travels farther per unit of fuel. With L/100 km, a lower number is better because it represents fewer litres consumed over 100 kilometres.
Common uses
- Checking a vehicle's real-world gas mileage
- Comparing US MPG with imperial MPG or L/100 km
- Estimating fuel cost for a completed trip
- Tracking changes after maintenance or driving adjustments
Helpful answers
MPG calculator FAQs
Learn more about gas mileage, fuel economy units, trip costs, and real-world MPG.
How do I calculate MPG?
Divide the distance driven in miles by the fuel used in gallons. For example, 300 miles divided by 10 gallons equals 30 MPG.
What formula does this calculator use?
The main formula is MPG = distance in miles ÷ fuel used in gallons. The tool converts kilometres, litres, and imperial gallons when other units are selected.
What is a good MPG?
A good MPG depends on the vehicle type, driving conditions, load, and model year. A higher MPG generally means the vehicle travels farther using the same amount of fuel.
Does this calculator support kilometres and litres?
Yes. You can enter distance in miles or kilometres and fuel in US gallons, imperial gallons, or litres. Results include US MPG, imperial MPG, km/L, and L/100 km.
What is the difference between US MPG and imperial MPG?
An imperial gallon is larger than a US gallon, so imperial MPG is numerically higher for the same fuel economy. This calculator displays both values clearly.
How is fuel cost calculated?
Trip fuel cost equals fuel used multiplied by the price per selected fuel unit. Entering a fuel price is optional.
Why is my real-world MPG different from the rated MPG?
Traffic, speed, weather, tyre pressure, terrain, idling, vehicle load, maintenance, and driving style can all make real-world fuel economy differ from official ratings.