Fuel cost calculator
Enter the distance, your car’s mpg and the gas price to see what the drive will cost in fuel.
The estimate updates as you type. Nothing you enter leaves this page.
Estimated trip fuel cost
$/ trip
- Gallons used
- gal
- Cost per mile
- $
- Cost per person
- $
Estimate from the numbers you entered.
How this is calculated
Gallons used are the distance divided by your miles per gallon. The fuel cost is those gallons times the price per gallon. For a round trip the distance is doubled first. Cost per mile is the price divided by mpg, and cost per person is the total divided by the number of people sharing.
cost = distance ÷ mpg × price per gallon
The method, the constants and the limits are written out in how fuel cost is calculated.
Worked example: 200 miles at 30 mpg
These are example numbers, not a current price. Distance 200 miles, 30 mpg, gas at $3.50 a gallon.
- 200 ÷ 30 = 6.67 gallons.
- 6.67 × $3.50 = $23.33 for the drive.
- Cost per mile: $3.50 ÷ 30 = $0.117.
Tick round trip and the distance becomes 400 miles: 13.33 gallons and $46.67. Split between four people, that is $11.67 each.
What the estimate leaves out
The result is one number from the inputs you gave, not a forecast of what the pump will show. Real fuel use moves with speed, traffic, hills, cold weather, a loaded car, a roof box and the air conditioning. Tolls, parking and wear on the car are not fuel and are not included. If your mpg is a rough guess, the cost is a rough guess by the same proportion.
To get a better mpg figure, work it out from a full tank with the fuel consumption calculator. If you are planning several stops, try the trip gas calculator, and to divide the bill fairly use the gas money calculator.
Common questions
Which mpg should I use?
Use the figure from your own fill-ups if you have one. A sticker or manual figure is a fair starting point, but highway and city driving usually give different results, so pick the one that matches the trip.
What gas price should I enter?
Enter the price at the station where you expect to fill up. The field starts with an example value because this page does not look up live prices, so replace it before you rely on the result.
How do I include the return journey?
Tick “Round trip”. The calculator doubles the distance before working out gallons and cost.
Can I use litres and kilometres?
This page uses US units. To compare fuel economy figures in both systems, use the mpg to L/100km converter.
Is what I type saved or sent anywhere?
No. The arithmetic runs in your browser. See the privacy policy for the details.
Other calculators handle monthly commuting costs, cost per mile and electric against gas. The formulas are in how fuel cost is calculated.
Calculators
- Cost per mile calculatorStart with fuel cost per mile, then add insurance, maintenance and depreciation to see the full cost and compare it with a rate you type in.
- EV charging costEnter the battery size, the start and end charge and your price per kWh to see the cost of one charge, per mile and per month.
- Fuel consumptionTurn a fill-up into your real mpg and L/100km, or work out how many gallons a distance needs.
- Trucking cost per mileEnter your own monthly costs and miles to get the cost per mile and the break-even rate each loaded mile must earn.
- EV vs gas costCompare the yearly energy cost of a gas car and an electric car on your own miles, prices and efficiency.
- MPG to L/100kmConvert US miles per gallon to litres per 100 km, or back, with the formula and the constants it uses.
- Trip gas calculatorAdd up to six legs, enter your mpg and the gas price, and see the cost of each leg, the total and how many tanks the trip needs.
- Gas money calculatorSplit the fuel cost of a trip between riders and the driver, with tolls added and each share rounded up to the cent.
- Monthly fuel costEnter your commute, days per week, mpg and gas price to see what you spend on fuel each week, month and year.
Guides
- How much gas will I use on my trip?Divide the miles by your car's mpg to get gallons, then use your tank size minus a reserve to plan fill-ups. Three worked examples show the arithmetic.
- How fuel cost is calculated: formulas and assumptionsThe formulas and constants behind every calculator on the site, each with a worked example and a source, plus what the results leave out.