PlenumHubThe formula
Each leg is worked out on its own, then the legs are added up. For each leg: fuel = miles ÷ mpg (or km × L/100 km ÷ 100), and cost = fuel × price. The trip total is the sum of all the legs.
For example, a three-leg trip of 120, 250 and 180 miles in a car that does 28 mpg, with fuel at $3.40 a gallon: leg 1 uses 120 ÷ 28 = 4.29 gallons and costs $14.57, leg 2 costs $30.36 and leg 3 costs $21.86. The whole 550-mile trip uses 19.6 gallons and costs $66.79.
Planning tips
Splitting a trip into legs makes it easy to see where the money goes, share costs fairly when different people join for different parts, or budget day by day. Get each leg's distance from a map or route planner, and remember to include the drive home if you're coming back the same way.
If fuel prices vary a lot along your route, for example between countries or states, calculate those legs separately with each area's price and add the results together.
Limits of this estimate
Motorway driving at high speed, mountains, headwinds, a fully loaded car, a roof box or towing can all use noticeably more fuel than your usual average. City driving and traffic jams can also increase fuel use. Treat the result as a budget estimate and allow a margin of 10-20% for a long or heavily loaded trip.
Frequently asked questions
How many legs can I add?
As many as you like. Use the "Add another leg" button to add a row, and the × button to remove one. Empty legs are ignored.
Can I use a different fuel price for each leg?
This calculator uses one price for the whole trip. If prices differ a lot along the way, calculate those legs separately with each price and add up the results.
How do I split the cost between passengers?
Divide the total by the number of people. If people join for different legs, add up the cost of the legs each person was on.
Which mpg does the imperial option use?
US mpg. If your car is rated in UK mpg, multiply it by 0.833 to get US mpg, or use the Fuel Economy Converter.