How to use the fuel cost calculator
- Choose Fuel cost of a trip or My fuel economy (MPG).
- Pick US units (miles, gallons) or metric (kilometers, liters).
- For a trip, enter the distance, your car's fuel economy and the fuel price. Tick round trip to double the distance.
- To split the cost, open More options and enter the number of people.
Formula
Gallons = miles / MPG
Cost = gallons x price per gallon
MPG = miles / gallons used
Metric: liters = km x (L per 100 km) / 100
Fuel prices are entered by you because they change daily and by location. SumPanda does not look up live prices.
Worked example: a 420-mile drive
The car gets 28 MPG and gas is $3.45 a gallon. Gallons: 420 / 28 = 15. Cost: 15 x $3.45 = $51.75, which is about 12 cents a mile.
As a round trip the distance doubles to 840 miles, so the cost is $103.50. Shared by three people, that is $34.50 each.
To find your own MPG, divide miles driven by gallons added at the next fill-up: 420 miles on 14.5 gallons is 28.97 MPG.
Getting a realistic MPG
The sticker MPG is a test result. Real economy is lower in cold weather, at highway speeds above about 65 mph, with roof racks or heavy loads and in stop-and-go traffic. For the best estimate, measure your own: fill the tank, reset the trip meter, drive normally and divide miles by gallons at the next fill-up.
Ways to lower a trip's fuel cost
Keep tires inflated to the pressure on the door-jamb label, remove roof boxes when not in use, avoid hard acceleration and use cruise control on flat highways. Each can improve economy by a few percent, and the savings add up on a long drive.
Assumptions and limits
- Fuel economy and price are constant for the whole trip.
- Electric and hybrid vehicles can be estimated using an equivalent MPG, but charging costs are not modeled.
- Tolls, parking and wear are not included.
- Metric mode uses L/100 km, where a smaller number is better economy.
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.
How do I convert MPG to L/100 km?
Divide 235.215 by the MPG. 28 MPG is about 8.4 L/100 km. The calculator does this for you in MPG mode.
How do I split fuel costs?
Enter the number of people in More options and the calculator divides the total.