Fuel Cost Calculator
Estimate trip fuel costs or find your real consumption
Fuel needed
L
Total cost
Cost per km
Per person
Actual consumption
L/100km
MPG (US)
How to Use
- Pick a mode — Choose “Trip estimate” to plan fuel costs before a journey, or “Actual efficiency” to compute your car’s real consumption from a fill-up.
- Choose your units — Toggle between km · L/100km (price per liter) and mi · MPG (price per gallon). The default follows your language, and results update instantly when you switch.
- Enter your numbers — For a trip: distance, your vehicle’s efficiency, the fuel price, and how many people are splitting the cost. For actual efficiency: the distance since the last fill-up and the fuel you put in.
- Read the results — The trip mode shows fuel needed, total cost, cost per km or mile, and the per-person share. The actual mode shows your real consumption in both L/100km and MPG.
Features
- Two modes — Estimate what a trip will cost before you leave, or measure what your car actually consumed after a fill-up.
- Metric and US units — km with L/100km and price per liter, or miles with MPG and price per gallon, with per-locale defaults and a one-click toggle.
- Cost splitting — Divide the trip cost across passengers for fair carpooling math.
- Exact conversion constants — Uses the international 1.609344 km-per-mile and 3.785411784 L-per-US-gallon factors, so metric and US results always agree.
- 100% client-side — No data leaves your browser.
Use Cases
- Road trip budgeting: You’re driving 800 km in a car that uses 7 L/100km with fuel at 1.80/L — see at a glance that you’ll need 56 liters and about 100.80 in fuel, or 25.20 per person with four people aboard.
- Carpool splitting: Three colleagues share a 60-mile daily commute — enter the distance, 30 MPG, the local price per gallon, and 3 people to get each person’s fair share.
- Reality check on the spec sheet: The brochure says 5.5 L/100km, but your fill-ups say otherwise — use the actual-efficiency mode to see your real number and what it costs you per kilometer.
Related Tools
- Tip Calculator — split restaurant bills the same way you split fuel costs.
- Discount Calculator — work out sale prices and savings.
- Unit Converter — convert between other measurement units.
Frequently Asked Questions
How do I convert between L/100km and MPG?
The two units are inverses of each other: L/100km measures fuel per distance, MPG measures distance per fuel. Multiply one by the other and you always get about 235.2 (using US gallons) — so 8 L/100km is about 29.4 MPG, and 30 MPG is about 7.8 L/100km. The unit toggle in the calculator does this conversion for you automatically.
How do I measure my car's real fuel consumption?
Use the fill-up method: fill the tank completely and reset the trip odometer, drive normally, then fill up again and note how much fuel it took. Enter the distance driven and the fuel used into the 'Actual efficiency' tab. For a stable figure, average over several tanks — one tank can be skewed by traffic, weather, or a mostly-highway route.
Does this calculator support electric cars?
No. EV energy use (kWh/100km) and electricity pricing (time-of-use tariffs, charging losses, fast-charging premiums) are a different domain with different inputs. This tool is for gasoline and diesel vehicles only.
Is the MPG figure US or imperial?
US MPG, based on the US liquid gallon of exactly 3.785411784 liters. Imperial (UK) MPG is about 20% larger for the same consumption, so don't mix the two when comparing figures.
Does the calculator store any of my data?
No. All calculations run entirely in your browser — no distances, prices, or consumption figures ever leave your device.