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- Works out how much fuel a trip will use and what it will cost.
- Works in miles and mpg, or km and L/100 km.
- Handles one-way and round trips.
- Splits the cost between passengers and shows cost per mile or km.
How to use the fuel cost calculator
Choose US or metric units
Miles and mpg, or km and L/100 km.
Enter the trip distance
For example 300 miles.
Enter your car’s fuel economy and fuel price
For example 28 mpg and $3.50 per gallon.
Choose one way or round trip
And how many people share the cost.
How trip fuel cost is calculated
Divide the distance by your fuel economy to find how much fuel you need, then multiply by the price. Real fuel use changes with speed, traffic, load and weather, so treat the result as an estimate.
Fuel cost formulas
US: fuel (gallons) = miles ÷ mpg
Metric: fuel (liters) = km × L/100 km ÷ 100
Cost = fuel × price per gallon or liter
Example 1: a 300-mile trip
28 mpg at $3.50 a gallon.
- Fuel needed 10.71 gallons
- Fuel cost $37.50
- Cost per mile $0.125
Example 2: round trip shared by 3
The same trip there and back.
- Total cost $75.00
- Each person $25.00
Example 3: metric
500 km at 7.5 L/100 km, 1.60 per liter.
- Fuel needed 37.5 liters
- Fuel cost 60.00
Ways to cut fuel costs
Drive steadily
Smooth speed uses less fuel than hard acceleration.
Check tire pressure
Low tires raise fuel use.
Lighten the load
Extra weight and roof boxes cost fuel.
Share the ride
Splitting the cost makes trips cheaper.
Find your car’s real mileage with the MPG calculator, plan travel time with the speed distance time calculator, or work out driving costs with the gig driver cost per mile calculator.
Fuel cost calculator FAQ
How do I calculate gas cost for a trip?
Divide the miles by your mpg, then multiply by the price per gallon.
How much does a 300-mile trip cost at 28 mpg?
At $3.50 a gallon, about $37.50.
How do I convert L/100 km to mpg?
Divide 235.215 by the L/100 km figure.
Should I use city or highway mpg?
Use the one that matches most of your trip, or a combined figure.
How do I split gas money?
Divide the total fuel cost by the number of people.
Does this include tolls or parking?
No. It covers fuel only.