Travel & Transport
Gas Mileage Calculator
Calculate your car's fuel economy (MPG or L/100km) from your fill-up distance and fuel used, and estimate trip fuel costs.
Fuel economy
30 MPG
Estimate a trip's fuel cost
$
Estimated fuel cost: $14.00
How the Gas Mileage Calculator works
Enter the miles driven and gallons used on a fill-up to calculate your real-world MPG, then use that figure to estimate the fuel cost of any future trip.
Frequently asked questions
How do I measure gallons used accurately?
Fill your tank completely, reset your trip odometer, drive normally, then fill up again — the gallons needed to refill is your gallons used for that distance.
Can I estimate the cost of a road trip?
Yes — once you know your MPG, enter your trip distance and gas price to estimate total fuel cost.
Guides that cover this
Practical Math for Smarter TravelFuel costs, EV charging, jet lag, and packing — the calculations that make trip planning less stressful.Calculating Real-World Fuel Economy From a Fill-Up, Step by StepA worked example calculating actual MPG from a real fill-up, using odometer readings and gallons purchased.Why Your Calculated MPG Doesn't Match the Sticker EstimateThe common reasons real-world calculated fuel economy differs from a vehicle's official EPA-estimated MPG rating.City vs. Highway MPG: Why the Same Car Gets Different MileageWhy a vehicle's fuel economy differs meaningfully between city and highway driving, and what drives that difference.How to Use the Gas Mileage CalculatorA quick walkthrough of calculating your car's real-world fuel economy from a fill-up.Gas Mileage Calculator: How It Works and How to Use ItA quick guide to the gas mileage calculator — what it calculates, how the math works, and tips for getting an accurate result.