Fuel Cost Calculator
Enter Metric, US, UK practical, or full Imperial trip inputs to calculate fuel use, trip cost, and an equal split.
Fuel Cost Calculator
Finance & Everyday · Mobility
Kilometres, litres per 100 km, and your price per litre.
Enter the distance for one direction.
Enter the price in your own currency.
Leave this at 1 when you are travelling alone.
Return trip options
Enter a distance, consumption, and fuel price to see the result. The cost split starts at one person.
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Fuel cost examples by trip and unit
| Trip | Distance, consumption and people | Fuel, total and equal share |
|---|---|---|
| Carpool to work | 50 km one way at 6 L/100 km, 2 people | 3 L at P/L → 3P total, 1.5P each |
| Return from a concert | 50 km each way at 6 L/100 km, 3 people | 6 L at P/L → 6P total, 2P each |
| US road trip | 100 mi one way at 25 US mpg, 2 people | 4 US gal at P/US gal → 4P total, 2P each |
| UK lift to the airport | 100 mi one way at 50 Imperial mpg, 2 people | 9.09218 L at P/L → 9.09218P total, 4.54609P each |
| Imperial touring trip | 100 mi one way at 50 Imperial mpg, 2 people | 2 Imperial gal at P/Imperial gal → 2P total, P each |
Which fuel cost formula should I use?
Work out how much fuel the car will use on your route, then multiply by your pump price. If you fill the tank before a weekend away, the receipt can include fuel you’ll still have on Monday. Use the receipt’s price per litre or gallon to estimate what the weekend drive itself costs.
- Metric. Divide trip kilometres by 100, then multiply by the car’s consumption in L/100 km. The result is in litres, ready to multiply by your price per litre.
- US or full Imperial. Divide trip miles by mpg, then multiply by the price per gallon. Both figures must use the same gallon. You can also divide price per gallon by mpg to get a cost per mile, as in the US Department of Energy and EPA’s “Understanding the Charts” formula for cost per 100 miles.
- UK practical. If your dashboard shows Imperial mpg and the pump sells by the litre, enter both as shown. The calculator converts the gallons used into litres before applying your price. The UK Vehicle Certification Agency’s fuel cost formula pairs these same inputs.
The exact conversions are 1 international mile = 1.609344 km and 1 US liquid gallon = 3.785411784 L. See NIST Handbook 44, Appendix C, pages C-22 and C-16. An Imperial gallon is larger at 4.54609 L, as defined in the UK Weights and Measures Act 1985, Schedule 1, Part VI, “Measurement of capacity”.
HowMuchTools checked the unit definitions and formulas on . Alexander Linack is responsible for the site’s content. See how we document our calculations or contact the publisher about a correction.
Which distance should I enter for a return trip?
Use the return-trip switch when the distance, fuel economy, pump price and paying group are the same both ways. Enter only the outward distance. If you copied the whole itinerary from a map, leave the switch off to count each mile once.
Suppose you’re driving straight to a festival on Friday but taking a friend home via another town on Sunday. Price each leg separately using its own distance and the people riding that day. Keep campsite supplies on a separate list with the Festival Survival Calculator.
How do I split fuel cost when someone joins halfway?
Split the drive at the pickup point. Share the fuel for the first stretch among the people paying for that stretch, then include the new passenger for the rest. Someone who rode the whole way pays their share of both stretches. If the group agreed to cover the driver’s fuel, count only the people contributing.
The split covers fuel only. Settle parking and tolls separately using the actual charges. For other travel calculations, browse the mobility tools in the Finance guide.
Fuel cost calculator FAQs
In Metric mode, fuel used equals total trip distance multiplied by consumption in litres per 100 kilometres, divided by 100. In US or Imperial modes, the calculator first converts your mpg and gallon inputs to that same base; fuel cost then equals fuel used multiplied by the price you enter. It uses one-way distance unless you select the return trip.
Calculate the fuel-only trip cost, then divide it by the number of people sharing the cost. Include the driver only when the group has agreed that the driver pays an equal share.
Yes, when you select the return-trip switch. It doubles the one-way distance before calculating fuel used and fuel cost; it does not double your price. Leave it off for a one-way journey, or calculate different legs separately when their inputs differ.
No. It calculates fuel only from the distance, consumption, fuel price, and number of people you enter. Tolls, parking, wear, taxes, and other vehicle costs are outside this model.