Fuel Cost Calculator

What is a Fuel Cost Calculator?

A fuel cost calculator turns three everyday numbers — how far you are driving, how efficiently your vehicle uses fuel, and the price of that fuel — into the litres (or gallons) the trip will burn and the money it will cost. It is the quick way to budget a road trip, compare two routes or two cars, or work out a fair share when several people travel together. Because fuel economy is written differently around the world, this tool accepts all three common conventions: kilometres per litre (km/L), litres per 100 kilometres (L/100km), and miles per US gallon (mpg). It converts between them internally, so you can enter whatever your dashboard or owner's manual shows and still get an accurate result. The cost is left currency-neutral — you supply the price and an optional currency label — so it works just as well for petrol in Tokyo as for gas in Texas or diesel in Berlin.

How to use this calculator

1. Enter the trip distance. In km/L and L/100km modes this is in kilometres; in mpg mode it is in miles. 2. Enter your fuel economy and pick its unit (km/L, L/100km or mpg). 3. Enter the fuel price — per litre for the metric units, per gallon for mpg. 4. Optionally type a currency label so totals read like '8,500 JPY'. 5. Toggle round trip if you are returning, and set the number of people to split the cost. The fuel needed, total cost, per-person cost and cost per distance update instantly.

Formula & Conversions

Fuel needed and cost come from: Fuel = distance ÷ economy (for km/L and mpg) or distance × economy ÷ 100 (for L/100km) Cost = fuel × price Round-trip cost = one-way cost × 2 Per person = total cost ÷ people For example, 500 km at 10 km/L with a price of 170 per litre needs 50 L and costs 8,500 (17,000 round trip). In mpg: 100 miles at 23.5 mpg with a price of 3.5 per gallon needs about 4.26 gallons and costs about 14.9. Economy units convert as km/L = 100 ÷ (L/100km) and 1 mpg ≈ 0.4251 km/L, so 20 km/L equals 5 L/100km.

Interpreting Results

The total cost is your headline fuel budget for the trip; the round-trip figure assumes the return leg uses the same economy, which is usually a good approximation. 'Fuel needed' helps you judge how many fill-ups you will make and whether a tank is enough. 'Cost per kilometre' (or per mile) is handy for comparing vehicles or for reimbursing mileage, though remember real fuel use rises with high speeds, heavy loads, hills, cold weather, air-conditioning and city stop-start traffic, so treat the estimate as a planning baseline rather than an exact bill. Tolls, parking and wear are not included. When splitting with friends, the per-person amount is an even split; adjust it if some travel only part of the way.

Frequently Asked Questions