MPG Calculator
Find your car’s real miles per gallon and what it actually costs to drive, from a tank of gas.
Fuel-tracking apps and efficient cars
Learn moreMeasure the real number
The window-sticker MPG is a lab estimate; your real-world economy depends on driving style, terrain, weather and load. Measuring a few tanks gives a truer figure — and turning it into cost per mile makes fuel costs easy to compare across vehicles.
How it’s calculated & sources
MPG = miles driven ÷ gallons used. Cost per mile = gas price ÷ MPG. Annual cost assumes 12,000 miles, near the U.S. average.
Benchmark: new U.S. light-duty vehicles average roughly 26 mpg in real-world driving (EPA, 2024).
Results update as you type and are general estimates, not personalized financial, tax, medical or legal advice. Verify with a professional.
Worked example
320 miles on 11 gallons is 29.1 mpg; at $3.50/gallon that’s about $0.120/mile, or roughly $1,440 a year over 12,000 miles.
Frequently asked questions
Why is my MPG below the sticker?
City driving, short trips, cold starts, roof racks and aggressive acceleration all cut economy. Steady highway driving gets closest to the rating.
How can I improve it?
Keep tires properly inflated, lighten the load, slow down on the highway, and combine trips so the engine stays warm.