Road Trip Gas Calculator

Find out what the fuel for a road trip will cost before you set off. Enter the distance, your car’s fuel economy and the fuel price, in miles or kilometres, mpg, L/100 km or km per litre, per gallon or per litre, and the calculator gives the fuel needed, the total cost, the cost per mile or kilometre and each person’s share.

How to use this tool

1. Enter the one-way distance from your map app and tick “Round trip” if you are coming back the same way.
2. Enter your fuel economy and pick its unit.
3. Enter the fuel price, say whether it is per gallon or per litre, and choose the currency.
4. Add how many people are splitting the cost.

Formula

Fuel = distance ÷ economy (or distance × L/100 km ÷ 100); Cost = fuel × price

Units are converted exactly: 1 mile = 1.609344 km, 1 US gallon = 3.785411784 L and 1 UK gallon = 4.54609 L. That makes L/100 km = 235.215 ÷ US mpg, or 282.481 ÷ UK mpg, so you can mix units freely, for example a UK car rated in mpg filling up at a price per litre.

Example

A 300-mile drive in a car that averages 28 mpg uses 300 ÷ 28 = 10.71 gallons. At $3.50 a gallon that is $37.50 of fuel, about 12.5 cents a mile. Made as a round trip and split between two people, it is $75 in total and $37.50 each.