How is the fuel cost calculated?

Imperial: fuel used (gallons) = distance ÷ mpg; cost = fuel used × price per gallon. Metric: fuel used (litres) = distance × L/100km ÷ 100; cost = fuel used × price per litre. The per-person cost is the total divided by the number of people.

What fuel price should I enter?

Enter the pump price in your local currency. In the UK this is typically pence per litre (e.g. 160 = £1.60/litre). In the US it is dollars per gallon. The calculator works with any currency — just keep the price and the result in the same unit.

Is the UK mpg the same as the US mpg?

No. The imperial (UK) gallon is about 4.546 litres and the US gallon about 3.785 litres, so a UK mpg figure is roughly 20% higher than the US figure for the same car. Enter the mpg that matches the gallon your fuel price is quoted in.

How do I convert mpg to L/100km?

For imperial mpg: L/100km = 282.5 ÷ mpg. So 40 mpg (UK) is about 7.1 L/100km. Switch the calculator to metric and enter the L/100km figure directly if that's what your car displays.

How do I split a road trip fuel cost fairly?

Enter the number of people in the "split between" field (up to 20). The calculator divides the total fuel cost evenly and shows the per-person share alongside the total.

Does this include tolls, parking or wear and tear?

No — it estimates fuel only. For the full cost of a trip add any tolls, congestion charges, parking and a rough allowance for maintenance separately.

Completely. All calculations happen inside your browser. No distances, prices or vehicle data are ever sent to a server.

Fuel Cost Calculator

Fuel cost calculator — metric and imperial

Work out exactly how much fuel a journey will cost before you set off — for trip budgeting, comparing two routes, or splitting petrol money on a road trip. Works whether your car reports miles per gallon or litres per 100 km, and in any currency.

How it works

In imperial mode the fuel used is distance ÷ mpg gallons and the cost is fuel used × price per gallon. In metric mode the fuel used is distance × (L/100km) ÷ 100 litres and the cost is fuel used × price per litre. If you set the number of people above one, the per-person figure is simply total cost ÷ people. Enter the price in whatever unit your country quotes (pence or pounds per litre, dollars per gallon) — the result comes back in that same currency.

Example

A 240-mile trip in a car doing 40 mpg, with fuel at £6.50 per imperial gallon: fuel used is 240 ÷ 40 = 6 gallons, so the cost is 6 × 6.50 = £39.00. Split between 3 people that’s £13.00 each.

Distance	Efficiency	Price	Fuel used	Total
100 mi	35 mpg	£6.50/gal	2.86 gal	£18.57
240 mi	40 mpg	£6.50/gal	6.00 gal	£39.00
160 km	7 L/100km	£1.60/L	11.2 L	£17.92
500 km	6 L/100km	£1.60/L	30.0 L	£48.00

All calculations run entirely in your browser — nothing is uploaded or stored.