Planning a road trip or a long commute? This fuel cost calculator estimates how much you'll spend on gas from three numbers you already know: the distance, your vehicle's fuel economy, and the local fuel price. It works in US units (MPG, price per gallon) or metric — switch the efficiency unit to km/L or L/100km and price per liter, whichever your country uses.
How trip fuel cost is calculated
Divide the trip distance by your fuel economy to get gallons burned, then multiply by the pump price. Worked example: a 300-mile trip in a car that gets 30 MPG uses 10 gallons; at $3.50 per gallon, the fuel bill is $35. Toggle round trip to double the distance automatically, and enter kilometers if that's how you navigate — the calculator converts.
Finding your real-world MPG
The window-sticker figure is optimistic for most driving. For an accurate number, use your car's trip computer, or calculate it at the pump: fill the tank, reset the trip odometer, drive normally, then divide miles driven by gallons at the next fill-up. Highway MPG typically runs 15–25% better than city; a heavy load, roof box or aggressive acceleration all push it down.
Cutting the cost of a trip
Small habits add up: keeping tires properly inflated (up to ~3% better economy), cruising at 65 instead of 75 mph (often 10–15% better), removing roof racks when unused, and combining errands while the engine is warm. Over a 1,000-mile trip at $3.50/gal, improving from 25 to 30 MPG saves about $23.
Cost per mile and sharing the bill
Divide the total by the distance to get your cost per mile — handy for expensing or comparing against transit. Splitting fuel with passengers? Divide the result per person with the split calculator, and convert distances with the length converter if your route mixes miles and kilometers.