Fuel cost calculator
Enter the trip distance, your car's average consumption and the fuel price. We instantly work out the litres needed, the trip cost, the round trip and your monthly spend.
Frequently asked questions
How is the fuel cost of a trip calculated?+
Litres = distance ÷ 100 × consumption (L/100km). Cost = litres × price per litre. For example, 100 km at 6.5 L/100km is 6.5 litres; at €1.65/L, the trip costs €10.72.
What average consumption should I enter if I don't know it?+
A petrol car in town uses about 7-8 L/100km, a diesel 5-6 L/100km and a hybrid 4-5 L/100km. You'll find it in the logbook or the trip computer.
Where do I get the current fuel price?+
You can check the daily average price on the benzly map, which uses official ministry data. Enter that price here for a realistic estimate.
How much do I spend on fuel per month commuting?+
Multiply the round-trip cost by your working days: the calculator uses 22. Example: 20 km each way at 7 L/100km with fuel at €1.65/L is €2.31 one way, €4.62 round trip and €101.64 a month.
How much does fuel cost per kilometre?+
Cost per km = consumption ÷ 100 × price per litre. At 6.5 L/100km with fuel at €1.65/L it comes to about €0.11/km; roughly €0.10–0.13/km for consumption between 6 and 8 L/100km.
Does it work for diesel or hybrid cars too?+
Yes: the formula is identical. Enter your car's consumption and the diesel price instead of the petrol price. A diesel typically sits at 5-6 L/100km and a hybrid at 4-5 L/100km.
Does the round trip cost exactly double?+
The calculator doubles the one-way cost, which is the best prior estimate. In practice real consumption can differ between the two directions (hills, traffic, load), so use the average consumption of the full trip if you know it.
How fuel spend is calculated
The fuel cost of a trip comes from a two-step sum: litres = distance ÷ 100 × consumption (in L/100km) and cost = litres × price per litre. With the calculator's defaults — 100 km, 6.5 L/100km and €1.65/L — you need 6.5 litres and the trip costs €10.72.
Of the three inputs, the only one that depends on your car is consumption. The most reliable figure is the trip computer's after a few weeks of real use; if you only have the technical sheet's number, treat it as a starting point and adjust it with your fill-ups.
If you don't know your consumption, these references by car type are a good start:
| Consumption | Typical profile | Cost per 100 km |
|---|---|---|
| 5.0 L/100km | Hybrid | €8.25 |
| 6.0 L/100km | Diesel | €9.90 |
| 7.0 L/100km | Petrol | €11.55 |
| 8.0 L/100km | Petrol in town | €13.20 |
How much you spend on fuel per month
For a regular commute, the number that matters isn't the day's but the month's. The calculator works it out for you: it multiplies the round trip by 22 working days. With the defaults (100 km each way), the round trip costs €21.45 and the month comes to €471.90.
A more typical commuting example: 20 km each way at 7 L/100km with fuel at €1.65/L. The one-way trip costs €2.31, the round trip €4.62 and the month €101.64. Seeing the monthly spend at a glance is what actually drives decisions: car sharing, changing route or filling up elsewhere shows at the end of the month, not on a single trip.
The price per litre: the input that changes daily
Distance and consumption are stable; the price per litre isn't: it changes from station to station and day to day. On the fuel-price map you get the real price at every station in your area or along your route, with official ministry data updated daily. Enter that price here and the estimate becomes a useful figure.
To put what you pay in context, check prices by autonomous community or by province: if your usual price sits above your area's average, there's room to save without changing car or route.
Three levers to spend less
The formula has only three variables, so there are only three ways to lower the result:
- Fewer kilometres: batching errands and avoiding detours acts on the variable that multiplies the other two.
- Lower consumption: dropping 1 L/100km saves exactly one litre every 100 km — €1.65 at the default price. Over a month of 880 km (the 20 km-each-way scenario), that's €14.52 less.
- Better price: every 5 cents less per litre saves €0.05 × litres filled. On a 50-litre tank, €2.50 per fill-up.
Fuel only, or the full trip cost?
This calculator answers a single question: how much you spend on fuel — litres times price, nothing else. If you're after the full cost of a trip — fuel plus tolls, split among occupants — use the car trip cost calculator: it's the same fuel sum with the trip extras on top.
Next car, diesel or petrol? The diesel vs petrol comparison tells you how many kilometres a year it takes for diesel's premium to pay off. And if your route includes paid sections, estimate them with the toll calculator.