Fuel Economy Calculator
How do you measure vehicle fuel economy? Measure fuel economy in MPG, km/L, or L/100 km.
Interactive inputs
Live result
30.00
MPG
Change an input to update the diagram.
Answer first
How do you measure vehicle fuel economy?
The Fuel Economy Calculator measures vehicle efficiency in multiple units simultaneously: MPG, km/L, and L/100 km from a single set of inputs. Perfect for international drivers, vehicle importers, or anyone comparing fuel economy data across different measurement standards.
Current calculator output
30.00
MPG
How it works
Fuel Economy Calculator: inputs, formula, and result
Enter the values that describe your high priority scenario. The interactive result changes as the inputs change, helping you compare fuel efficiency, fuel consumption, fuel cost, or operating impact.
Formula
MPG = Distance ÷ Fuel; km/L = MPG × 0.425144; L/100 km = 235.215 ÷ MPG
Worked example
360 miles on 12 gallons = 30 MPG = 12.75 km/L = 7.84 L/100 km.
Pro tip: When comparing vehicles from different markets, always convert to a single unit first. A European car at 5 L/100 km equals 47 MPG.
Personalized guidance
What changes the result for Fuel Economy?
Use this focused fuel-economy tool to get a direct answer for a common driving-cost question. Traffic, tire pressure, vehicle load, terrain, driving style, weather, fuel price, and the quality of the input data can change the final result.
Estimated result condition
100%
Select factors that match this high priority calculation.
When should you use this calculator?
Use it before a trip, after a fill-up, when comparing vehicles, or when documenting business mileage. Keep the same units and use several measurements when you need an average.
Selected usePlan with Fuel Economy Calculator
FAQ
FAQs about Fuel Economy
3 questions
Question 1 of 3 is open
What is the most accurate way to measure fuel economy?
The full-tank method: fill completely, drive a full tank, fill again, then divide distance by fuel added. Onboard estimates can be off by 5-10%.
How do EPA fuel economy ratings work?
The EPA tests on a dynamometer simulating city and highway cycles. Results are adjusted downward (about 20% city, 13% highway) to approximate real-world driving.
Why do some countries use L/100 km instead of MPG?
L/100 km scales linearly with cost, making calculations straightforward. MPG is inversely related to cost, which is less intuitive for comparisons.
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