Calculator Tools
Fuel Economy Calculator
Calculate fuel economy in MPG (US), MPG (UK), L/100km, and km/L from distance and fuel used. Add fuel price for cost per mile, cost per 100 km, and trip cost.
Unit system
Switch unit system to relabel the inputs. The result panel always shows every common economy unit.
Input mode
Use this when you already know how far you drove and how much fuel you used.
Trip data
How far you drove on the fuel you used.
Volume of fuel consumed across that distance.
Optional cost
Leave blank to skip cost. Sample values are rough mid-2020s averages.
Optional. Multiplies the computed economy by this distance to project fuel and cost for an upcoming trip.
Quick-fill examples
These are illustrative numbers, not specific vehicle claims. Adjust everything to match your own drive.
How to use
- Pick a unit system: US (miles + US gallons), UK (miles + imperial gallons), or metric (km + litres). The input labels update to match.
- Choose Distance and fuel for a known leg, or Two odometer fills for the brim-to-brim tank method. Enter your numbers.
- Optionally pick a currency, enter the fuel price (per gallon or per litre), and add a trip distance to project upcoming fuel and cost.
- Read the headline economy at the top of the result panel and the full unit grid below. Copy any single value or use Copy summary to grab the full report.
About this tool
Fuel Economy Calculator turns a distance and a fuel volume into every common fuel-economy unit at the same time. Pick the unit system that matches your dashboard and pump: US (miles plus US gallons), UK (miles plus imperial gallons), or metric (kilometres plus litres). The result panel always shows MPG (US), MPG (UK / imperial), L/100km, and km/L side by side, plus miles per litre and kilometres per US gallon for cross-border travel and motorbike riders. Two input modes are available. Direct mode is for when you already know the distance you drove and the fuel you used. Tank-fill mode follows the brim-to-brim method preferred by accuracy-minded drivers: enter the odometer reading at the previous fill, the odometer reading at this fill, and the fuel pumped at this fill (which replaced the fuel consumed in between). Add an optional fuel price and pick a currency to see cost per mile, cost per kilometre, cost per 100 km, total fuel cost for the volume you entered, and a projected trip cost when you provide an upcoming trip distance. All math runs locally in your browser, so your odometer readings, fuel purchases, and prices never leave your tab.
Free to use. Works in your browser. No signup, no login.
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