Fuel Efficiency Comparison Tool
Which vehicle has better fuel efficiency? Compare MPG, km/L, L/100 km, and cost per mile.
Interactive inputs
Live result
30.00
MPG
Change an input to update the diagram.
Answer first
Which vehicle has better fuel efficiency?
The Fuel Efficiency Comparison Tool lets you pit two vehicles against each other on the same drive to see which uses less fuel and costs less. Enter a common distance and fuel used by each vehicle to compare MPG, cost, and consumption side by side.
Current calculator output
30.00
MPG
How it works
Fuel Efficiency Comparison Tool: inputs, formula, and result
Enter the values that describe your supporting scenario. The interactive result changes as the inputs change, helping you compare fuel efficiency, fuel consumption, fuel cost, or operating impact.
Formula
Vehicle A MPG = Distance ÷ A Fuel; Vehicle B MPG = Distance ÷ B Fuel
Worked example
Both drive 360 miles. Vehicle A uses 12 gal (30 MPG), Vehicle B uses 10 gal (36 MPG). B is 20% more efficient.
Pro tip: A 5 MPG improvement matters much more at low MPG values. Going from 15 to 20 MPG saves more fuel per mile than going from 35 to 40 MPG. This is called the MPG illusion.
Personalized guidance
What changes the result for Fuel Efficiency Comparison?
Explore a focused fuel-economy variable and see how it changes cost, efficiency, or emissions. 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 supporting 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 Efficiency Comparison Tool
FAQ
FAQs about Fuel Efficiency Comparison
3 questions
Question 1 of 3 is open
What is the MPG illusion?
People overvalue MPG improvements at high values. Improving from 10 to 20 MPG saves 5 gallons per 100 miles. From 33 to 50 MPG saves only 1.3 gallons. Think in gallons per 100 miles instead.
How do I compare gas and diesel vehicle efficiency?
Compare cost per mile, not MPG. A diesel at 40 MPG ($4.20/gal) costs $0.105/mile vs. gas at 30 MPG ($3.50/gal) at $0.117/mile.
Does vehicle age affect fuel efficiency?
Modern vehicles (2015+) are 15-25% more fuel efficient than comparable 2005 models due to direct injection, turbocharging, and aerodynamic improvements.
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