Trip & budget
Fuel cost for 100 km: formula and examples
In metric markets, 100 km is the natural distance for a fuel estimate. It matches the L/100 km unit directly, and it is easy to scale to a longer trip.
Quick answer
At 7 L/100 km, 100 km uses 7 litres. Multiply by the price per litre to get cost. If your car uses km/L, litres used = 100 ÷ km/L.
Key takeaways
- With L/100 km, litres for 100 km is the same number.
- With km/L, divide 100 by the km/L figure.
- Cost = litres × price per litre.
Using L/100 km
L/100 km is already a per-100-km measure. A car listed at 6.5 L/100 km uses 6.5 litres over 100 km. At €1.75 per litre, the fuel cost is €11.38.
For a different distance, multiply the consumption figure by distance ÷ 100. For 250 km at 6.5 L/100 km, litres = 250 × 6.5 ÷ 100 = 16.25 litres.
litres = km × (L/100 km) ÷ 100 cost = litres × price per litre
Using km/L
Japan, India and South Korea often use km/L. At 15 km/L, 100 km uses 100 ÷ 15 = 6.67 litres. At 20 km/L, it uses 5 litres.
A higher km/L figure means lower fuel use. Do not multiply by km/L when you want litres; divide.
| km/L | Litres for 100 km | L/100 km |
|---|---|---|
| 10 | 10.0 | 10.0 |
| 15 | 6.67 | 6.67 |
| 20 | 5.0 | 5.0 |
| 25 | 4.0 | 4.0 |
Scaling to a longer trip
Once you know the fuel used for 100 km, scale it linearly. A 400 km trip uses four times the fuel. That is one advantage of consumption units: the arithmetic is direct.
Questions
How many litres is 100 km?
How many miles is 100 km?
How do I calculate 100 km in Japan or India?
Sources
- GOV.UK — weekly road fuel prices — UK price statistics for context, not a live station price.
- US EIA — gasoline and diesel prices — US regional and national averages.
- European Commission — Weekly Oil Bulletin — EU fuel price monitoring.
- fueleconomy.gov — US fuel-economy ratings — EPA label values, test-cycle context and consumer guidance.
Try the calculator
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A note on prices and rules
Page last reviewed: . Formulas are covered by automated tests. Prices are inputs, not live data.