Fuel Economy (L/100km)
Litres of fuel used per 100 km travelled.
Formula
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Example
40 L over 500 km: E = 8 L/100km
How it works
This formula converts a fuel-use rate into a standard distance basis: how many litres are needed to travel 100 km. It works by taking the actual fuel used, dividing by the distance travelled to get litres per kilometre, then multiplying by 100 so the result is easier to compare between vehicles and trips. A lower value means better fuel economy because less fuel is needed to cover the same distance.
When to use it
Use this when you want to calculate a car’s fuel consumption from a trip log, compare two vehicles, or check whether your driving or route was more or less economical. It is common in automotive reports, maintenance records, and fuel-cost planning.
Worked example, step by step
A van uses 18 L of fuel to travel 270 km. E = (100 × F) / d E = (100 × 18) / 270 E = 1800 / 270 E = 6.67 So the fuel economy is 6.67 L/100 km.
Common mistakes to avoid
- Putting distance in miles instead of kilometres without converting first
- Dividing distance by fuel used, which gives the wrong unit
- Forgetting to multiply by 100, which leaves the answer as L/km instead of L/100 km
Did You Know?
Europe measures fuel use as L/100km (lower is better) while the US uses mpg (higher is better) — inverse scales.
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