Fuel Consumption Calculator (L/100 km)
Enter your trip distance and fuel used to calculate your vehicle's fuel economy in litres per 100 kilometres.
What is litres per 100km?
Litres per 100km (L/100 km) is one of the most common fuel consumption metrics used around the world. It tells you how many litres of fuel a vehicle needs to travel exactly 100 kilometres. Lower numbers mean better efficiency. For example, a car that uses 5.8 L/100 km is more fuel-efficient than one using 9.4 L/100 km.
This metric is especially useful because it is direct and practical. Once you know your L/100 km figure, you can quickly estimate trip fuel costs, compare cars, and track how your driving habits affect expenses.
How to calculate L/100 km manually
If you prefer to do the math yourself, use this formula:
L/100 km = (Fuel used in litres ÷ Distance traveled in km) × 100
- If you used 42 litres over 600 km: (42 ÷ 600) × 100 = 7.0 L/100 km
- If you used 31.5 litres over 450 km: (31.5 ÷ 450) × 100 = 7.0 L/100 km
- If you used 58 litres over 700 km: (58 ÷ 700) × 100 = 8.29 L/100 km
Our calculator above does this instantly and also gives additional conversions like km/L and MPG.
Why this calculator is useful
- Track efficiency over time: Spot trends in fuel economy each week or month.
- Estimate cost per 100 km: Useful for budgeting commuting or road trips.
- Compare vehicles: Evaluate whether a new vehicle would lower your fuel bill.
- Measure driving changes: Test whether smoother acceleration improves consumption.
What counts as good fuel economy?
"Good" depends on vehicle size, engine type, road conditions, and load. As a rough guideline:
- Under 5.5 L/100 km: Excellent (common in hybrids and highly efficient compact cars)
- 5.5 to 7.0 L/100 km: Very good for many modern sedans and hatchbacks
- 7.0 to 9.0 L/100 km: Typical for midsize vehicles and mixed city/highway use
- Above 9.0 L/100 km: Common in larger SUVs, trucks, or aggressive city driving
The best comparison is with your own past data on similar routes.
Tips to reduce litres per 100km
1) Keep speed steady
Sudden acceleration and heavy braking waste fuel. Smooth, consistent driving usually gives the best economy.
2) Maintain tire pressure
Under-inflated tires increase rolling resistance, forcing the engine to work harder.
3) Remove unnecessary weight
Extra cargo and roof racks increase fuel consumption, especially at highway speeds.
4) Avoid prolonged idling
Idling burns fuel while you travel zero distance, which worsens your L/100 km value.
5) Follow maintenance schedules
Clean filters, proper oil, and healthy spark plugs (for petrol engines) all help maintain efficiency.
Common mistakes when calculating fuel economy
- Mixing miles with kilometres by accident.
- Using gallons instead of litres without conversion.
- Estimating fuel added rather than using actual pump data.
- Comparing short, stop-and-go trips against long highway trips.
For best accuracy, use full-tank-to-full-tank records over several fill-ups.
Quick FAQ
Is lower L/100 km always better?
Yes. Lower L/100 km means less fuel consumed per 100 km, which usually means lower cost and emissions.
Can weather affect my result?
Absolutely. Cold weather, strong winds, rain, and traffic congestion can all increase fuel use.
How often should I calculate fuel consumption?
A good habit is every fill-up. Tracking over time gives a more realistic average than one trip alone.
What if I only know MPG?
The calculator provides MPG estimates from your L/100 km result. You can compare both systems easily.
Final thoughts
Knowing your litres per 100km is one of the simplest ways to take control of driving costs. Use the calculator regularly, track results over time, and make small driving and maintenance improvements. Even modest gains in efficiency can save a meaningful amount of money over a year.