Gas cost calculator
Fuel cost for a trip or commute from miles, MPG and gas price, starting at the EIA national average.
- ๐บ๐ธ US federal & state rules
- EIA weekly U.S. regular gasoline price
- See sources
Gas cost, round trip
$77.34
17.86 gallons at $4.33 a gallon
- Gallons
- 17.86
- Cost per mile
- $0.15
- Distance
- 500 miles round trip
This is an example. Enter your numbers above and press the button to see your own result.
At other gas prices
| $3.33 a gallon | $59.48 |
|---|---|
| $3.83 a gallon | $68.41 |
| $4.33 a gallon | $77.34 |
| $4.83 a gallon | $86.27 |
| $5.33 a gallon | $95.20 |
- The default price is the EIA U.S. average for regular gas, $4.33 for the week of October 12, 2026. Prices in your area can be well above or below that.
- Real MPG drops with highway speeds above 60 mph, heavy loads, cold weather and idling.
Show the math
| Gallons | 500 miles รท 28 MPG = 17.857 |
|---|---|
| Cost | 17.857 ร $4.33 = $77.34 |
What to do next
How it works
Gallons used = miles รท MPG. Gas cost = gallons ร price per gallon. With round trip on, the distance is doubled. Cost per mile is the price divided by MPG, which is handy for comparing cars.
Things to keep in mind
Use the MPG you actually get, not the window sticker. Highway driving at 75 mph can use noticeably more fuel than the EPA highway rating, and short trips in winter use more too.
The starting price is a national average. Gas costs more in California and much of the West, and less in many Gulf Coast states, so check a local price before a long drive.
Sources
Rules applied as of 2026-10-12. See the sources below for details.
Frequently asked questions
How do I calculate gas cost for a trip?
Divide the miles by your MPG to get gallons, then multiply by the price per gallon. A 500 mile round trip at 28 MPG and $4.33 a gallon uses about 17.9 gallons, roughly $77.
Where does the default gas price come from?
It is the U.S. Energy Information Administration weekly average for regular gasoline, $4.331 for the week of October 12, 2026. Replace it with the price at stations on your route.
How do I split gas money on a road trip?
Enter the number of people and the calculator divides the total. Some groups leave the driver out of the split, so set the count to match how you share.