MPG Calculator
Work out your car's real miles per gallon. Free, instant and no sign-up.
How this MPG calculator works
Enter how many miles you drove and how many gallons of gas you used over those miles. The calculator shows your miles per gallon (mpg) and the gallons you burn every 100 miles. It uses your real driving, which is often different from the number on the window sticker.
The formula
Miles per gallon = miles driven ÷ gallons used. Gallons per 100 miles = gallons used ÷ miles driven × 100.
Example
If you drive 320 miles and use 10 gallons, your fuel economy is 320 ÷ 10 = 32 mpg, or 3.13 gallons per 100 miles.
How to measure your real mpg
- Fill the tank completely and reset your trip meter to zero.
- Drive as you normally would until the tank is about half empty or lower.
- Fill the tank completely again and write down the gallons the pump shows.
- Divide the miles on your trip meter by those gallons.
Repeat this over two or three tanks and average the results for a more reliable number.
Tips
Fuel economy changes with speed, tire pressure, cold weather, air conditioning use, cargo weight and city or highway driving. Once you know your mpg, use the Gas Cost Calculator to estimate what a trip will cost, or read how to calculate trip gas cost.
Frequently asked questions
What is a good mpg?
Many gasoline cars get 25 to 35 mpg in mixed driving. Hybrids often do better and large trucks and SUVs often do worse.
Why is my mpg lower than the sticker?
Real driving conditions, aggressive acceleration, short trips and cold weather all lower fuel economy.
Is my data saved?
No. Everything stays in your browser.