Gas cost calculator
Estimate the gas cost of a trip from the miles you'll drive, your car's mpg and the price per gallon, including a round trip and each person's share.
Verified October 21, 2026Parameters in effect since October 19, 2026EIA weekly U.S. average retail price, week of 2026-10-19: regular gasoline $4.284/gal, on-highway diesel $6.276/gal
Total trip cost
$51.41
- Total distance
- 300 mi
- Gallons needed
- 12 gal
- Price used
- $4.28/gal
- Fuel cost
- +$51.41
- Total trip cost
- $51.41
- * Price: $4.28/gal, U.S. average retail price for the week of October 19, 2026 (U.S. Energy Information Administration).
- * Real fuel economy depends on speed, load, traffic and air conditioning.
General information, not financial or investment advice.
FAQ
How is gas cost calculated?
Distance ÷ mpg × price per gallon. A 300-mile drive in a car that gets 25 mpg uses 12 gallons; at $4.284 a gallon that's $51.41.
Where does the default price come from?
It's the U.S. average retail price published weekly by the Energy Information Administration. Prices vary by state and station, so you can enter your own.
How is the cost split?
Fuel plus any tolls and parking you enter are added up and divided equally among the people on the trip.
What does round trip do?
It doubles the one-way distance you enter; tolls and parking stay as entered.