Fuel and car costs · rates of EIA and EPA
Gas cost calculator for a drive
Enter the distance, pick your state and your car (or type the MPG): the fuel cost uses the price EIA measured this week where you fill up.
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Fuel cost of the trip
$69
500 miles at 28.0 mpg
| Fuel: 17.9 gal × $3.874 | $69 |
| Fuel cost per mile | $0.138 |
| Tolls and parking | $0 |
| Same miles at the IRS business rate | $380 |
The IRS rate also pays for wear, insurance and depreciation, so it is higher than fuel alone. Prices: EIA retail averages; states without their own EIA series use their region. How this is calculated.
A 500-mile drive in a car that gets 30 miles per gallon burns about 16.7 gallons; at the U.S. average of $4.354 for regular gasoline in the EIA survey of October 5, 2026, that is $72.57. Where you fill up moves the answer more than most people expect: the same drive costs $63.82 at the Ohio average of $3.829 and $103.78 at the California average of $6.227. The calculator above starts from the EIA price of your state, or of its region when EIA does not survey the state on its own, and from the EPA combined MPG of sixteen common 2026 models. Type your own price or MPG to override them, switch to diesel, mark the distance as one way to double it, and share the cost between passengers. It also shows what the same miles would be worth at the IRS business rate.
Where the default price comes from
The Energy Information Administration publishes weekly average retail prices for the country, its regions and a handful of states and cities (Gasoline and Diesel Fuel Update); the calculator uses the latest week available when the site was built and says which one under the state field. Nine states have their own series: California, Colorado, Florida, Massachusetts, Minnesota, New York, Ohio, Texas and Washington. Every other state takes the average of its region, such as the Gulf Coast, the Midwest or the Lower Atlantic, which is an approximation: a station in a big-city suburb and one off a rural interstate in the same region can differ by more than the regional average suggests. That is why the price field stays editable.
Diesel follows the same regional series, except California, which has its own. In the week of October 5, 2026, diesel averaged $6.199 nationally against $4.354 for regular gasoline, a gap wide enough to matter for pickup and van owners who compare engines.
The MPG you should type
EPA combined MPG blends 55% city and 45% highway driving. On a long highway trip many cars beat it slightly; at high speed with a loaded roof box or a trailer they do worse. The presets come from the EPA fueleconomy.gov data for the plainest 2026 version of each nameplate: the 2026 Toyota Camry HEV FF LE is rated 51 mpg, the 2026 Ford F150 Pickup 2WD 19 mpg. On 500 miles at the national price, that gap is $42.69 against $114.58. Your dashboard average over the last few tanks beats any rating, and for a car you just bought, the window sticker shows the same EPA figures the presets use. If you track fill-ups, divide the miles since the last full tank by the gallons you just pumped: that is your real MPG for this kind of driving.
Fuel for a drive at U.S. average prices
Fuel cost
$46.65
| 10.7 gal × $4.354 | $46.65 |
| Per mile | $0.156 |
| Same miles at the IRS rate ($0.76) | $228 |
Fuel is not the cost of driving
For a business trip, the fuel figure understates what the car costs. The IRS business rate of 76 cents a mile since July 1, 2026 is built from fixed and variable costs: depreciation, insurance, registration, maintenance and tires as well as fuel. A 30-mpg car at the national price spends about $0.145 a mile on gasoline, roughly 19% of the rate. An employer that reimburses "gas only" is paying a fraction of the real cost; see the mileage reimbursement calculator for the tax side and the cost per mile calculator for your own car's figure.
Splitting with passengers and planning a longer trip
The "people sharing the cost" field simply divides fuel and tolls. For a trip with nights on the road, the road trip cost calculator adds rooms and meals, and the trip calculator handles a business trip with federal per diem. For an electric car, use the EV charging cost calculator, which works from kWh per 100 miles and the electricity price of your state.