How much gas a drive needs and what it costs at your price per gallon
Estimates only, not financial advice. What you type stays on your device. Checked against sources on 1 Oct 2026.A gas cost is the miles divided by your car's MPG, times the price per gallon. A 300-mile drive at 30 MPG uses 10 gallons, which costs $35.00 at $3.50 a gallon, about 11.7 cents a mile. Enter your own distance, MPG and pump price.
| MPG | Gallons | Cost | Cost a mile |
|---|---|---|---|
| 15 | 20 | $70.00 | 23.3¢ |
| 20 | 15 | $52.50 | 17.5¢ |
| 25 | 12 | $42.00 | 14¢ |
| 30 | 10 | $35.00 | 11.7¢ |
| 35 | 8.6 | $30.00 | 10¢ |
| 40 | 7.5 | $26.25 | 8.8¢ |
| 50 | 6 | $21.00 | 7¢ |
The page opens in miles, MPG and gallons; enter the "Distance, one way" in miles.
Enter your car's Fuel economy in MPG.
Enter the "Price per gallon" you pay at the pump.
Read the gas cost, the gallons of Fuel used and the Cost per mile.
The cost of a drive comes down to three numbers: how far, how much fuel the car uses for that distance, and what the fuel costs. This calculator takes them in whichever units your car and your country use, and gives the trip cost, each person's share and the cost per mile and per kilometre. Round trip doubles the one-way distance: 150 miles there and back at 25 MPG, with gas at $3.40, uses 12 gallons and costs $40.80.
Units. Choose miles with MPG and a price per U.S. gallon, kilometres with litres per 100 km, or kilometres with km per litre. Switching converts the figures already entered, so the trip stays the same trip. The conversions use the U.S. gallon of 231 cubic inches (3.785411784 litres) and the mile of 1.609344 km, both exact definitions in NIST Handbook 44. A UK MPG figure uses the larger Imperial gallon and is about 20% higher than the U.S. figure for the same car, so convert it to L/100 km before entering it.
Electric cars. Enter the car's energy use per 100 miles or 100 km and your price per kWh. Some energy is lost between the socket and the battery while charging; if you know the share for your charger, add it and the cost is worked out on the energy drawn from the wall.
The rest of the article, and all 6 questions about Fuel Cost Calculator, are on the Fuel Cost Calculator page.
Divide the distance by the car's miles per gallon to get the gallons used, then multiply by the price per gallon. A 300-mile drive at 30 MPG needs 10 gallons, and at $3.50 a gallon that is $35.00. Double it for a round trip, and divide by the number of people sharing the cost.
Divide 235.215 by the MPG figure. The constant is 100 times the litres in a U.S. gallon (3.785411784) divided by the kilometres in a mile (1.609344). So 30 MPG is 7.84 L/100 km and 25 MPG is 9.41 L/100 km. The same division works the other way, from L/100 km back to MPG.
Multiply the distance by the car's energy use and the electricity price. At 30 kWh per 100 miles, 300 miles takes 90 kWh, which costs $15.30 at 17 cents per kWh. Public fast chargers often cost several times the home rate, so enter the price you will actually pay.
No. A UK figure uses the Imperial gallon of about 4.546 litres, while the U.S. gallon is 3.785 litres, so the same car shows roughly 20% more miles per gallon in the UK. Enter a UK figure as L/100 km instead: divide 282.48 by the UK MPG to convert it.
Rates and rules change; check the source before you rely on a figure.
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