Gas Mileage (MPG) Calculator
Knowing your real gas mileage helps you plan trips and compare cars. Enter how many miles you drove, how many gallons you used and the price of gas to see the MPG and what each mile costs.
Your numbers
Result
- Fuel cost
- $42.00
- Cost per 100 miles
- $14.00
- Metrickm/L
- 10.63
- MetricL/100km
- 9.41
| Distance (mi) | Estimated cost |
|---|---|
| 100 | $14.00 |
| 500 | $70.00 |
| 1,000 | $140.00 |
How to calculate MPG
Gas mileage is miles ÷ gallons. If you drove 300 miles on 12 gallons, that is 300 / 12 = 25 MPG. For the cost per mile, multiply the gallons by the price and divide by the miles: (12 × $3.50) / 300 = $0.14 per mile. Higher MPG means fewer gallons — and less money — for the same distance.
How to measure it accurately
Fill the tank all the way and reset the trip odometer. Drive normally, then fill up again at the next stop: the gallons the pump adds are exactly what you burned over those miles. Repeating this over a few tanks — and in both city and highway driving — gives a more reliable average than a single fill-up.
MPG vs L/100km and km/L
The US measures fuel economy in miles per gallon (higher is better). Much of the world uses liters per 100 km (lower is better) or km per liter. This calculator shows all three so you can compare a US window sticker with a spec sheet from anywhere. As a rule of thumb, 25 MPG is about 9.4 L/100km.
Frequently asked questions
Sources
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