Fuel Needed50 L
One-way Cost8,500
Cost per km17
Formula
Fuel Needed = Distance ÷ km/L
Total Cost = Fuel Needed × Fuel Price (per litre)
500 km → 50 L → 8,500
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
How do km/L, L/100km and mpg relate? ▾
They all describe fuel economy but in different ways. km/L and mpg are 'distance per fuel' (higher is better), while L/100km is 'fuel per distance' (lower is better). km/L = 100 ÷ (L/100km), and 1 US mpg ≈ 0.4251 km/L. For example 20 km/L equals 5 L/100km.
Is this for petrol, diesel or electricity? ▾
It works for any liquid fuel — petrol, diesel, LPG — as long as you enter the matching economy and price. For electric vehicles the idea is the same but the units differ (kWh and price per kWh), so a dedicated EV calculator is more convenient.
Does the round-trip option double the cost? ▾
Yes. Round trip doubles the distance, so both the fuel needed and the total cost double, and the per-person and per-distance figures use that round-trip total.
Why is no currency symbol shown? ▾
To stay useful worldwide, results are plain numbers. Enter the price in your own currency and optionally add a currency label (like USD or JPY) that will be appended to the figures.
Estimates are for planning only. Real fuel consumption varies with driving style, speed, load, terrain, weather and traffic, and the figures exclude tolls, parking and vehicle wear.