Fuel Consumption Calculator
Enter liters filled and kilometers driven – calculate real fuel consumption instantly
- Updated
Litres shown on the pump when filling up, distance = odometer difference since the last full tank.
Consumption
7.00L/100 km
7.0035 L over 500 km means 7.00 L/100 km – economical.
Rough guide for cars; vans, SUVs and towing naturally use more.
How this was calculated
When you fill up completely, the amount added replaces exactly what was used since the last full tank.
Continue with this consumption
What does a trip cost?
How much CO₂ does the car emit?
RZ-26 · headon.pro
Calculating fuel consumption: method and practice
How to determine your vehicle's actual consumption
Knowing the actual fuel consumption of your vehicle is more valuable than the manufacturer figure. That is because the WLTP value quoted in advertising is measured under laboratory conditions and often deviates by 10–25% on the higher side in everyday driving. The formula is simple: consumption (L/100 km) = liters filled ÷ distance × 100. At 35 liters over 500 km, that works out to exactly 7.0 L/100 km.
For an accurate measurement, fill your vehicle to the brim and note the odometer reading. After a representative distance (at least 200 km, ideally 400–500 km), fill up again. Enter the liters filled and kilometers driven into the calculator. The longer the measured distance, the more accurate the result. One-off short trips (under 50 km) produce skewed values due to the cold-start phase.
Fuel consumption varies seasonally: in winter (below 5°C) it rises due to increased fuel demand during warm-up, cabin heating, heavier tires and cold engine-oil viscosity – by up to 20%. In summer, air conditioning use increases consumption by 0.5–1.5 L/100 km. Measured over a full year, this gives a more realistic annual consumption figure.
For your annual fuel costs, multiply your consumption by your annual mileage and the fuel price. At 7 L/100 km, 15,000 km/year and €1.80/L, that comes to: 7 × 150 × 1.80 = €1,890 per year. You can break this figure down in detail with our fuel cost calculator.
Reducing consumption: the most effective measures
Factors affecting fuel consumption
- Tire pressure: up to -0.3 L
- Underinflated tires increase rolling resistance and noticeably raise consumption
- Speed: quadratic effect
- At 160 km/h instead of 130 km/h, consumption rises by about 25–30%
- Air conditioning: +0.5–1.5 L
- AC use increases consumption; open windows instead when driving in the city
- Cold start: +15–20%
- Consumption is noticeably higher for the first 5–10 km
- Drive with foresight
- Use engine braking instead of the brake pedal; saves up to 10% fuel
- Avoid idling
- Switching off the engine after 30 seconds of waiting saves fuel
Calculation examples
- Filled
- 35.0 L
- Distance driven
- 500 km
- Consumption (35 ÷ 500 × 100)
- 7.0 L/100 km
- Filled
- 62.0 L
- Distance driven
- 520 km
- Consumption (62 ÷ 520 × 100)
- 11.92 L/100 km
Frequently asked questions about the fuel consumption calculator
Everything about calculating and evaluating fuel consumption
How do I calculate my car's fuel consumption?
The formula is: consumption in L/100 km = (liters filled ÷ kilometers driven) × 100. Fill your vehicle completely, reset the trip odometer to zero and drive a certain distance. Then fill up completely again and note the liters filled and kilometers driven. Example: 35 liters over 500 km = 7.0 L/100 km.
Why does my consumption differ from the WLTP value?
The WLTP test cycle is measured under standardized laboratory conditions and rarely reflects real-world consumption exactly. Factors that increase real consumption: frequent city driving with stop-and-go traffic, air conditioning use, towing a trailer or carrying roof loads, cold weather (below 0°C increases consumption by up to 20%), tire pressure below the recommended level, and highway driving above 130 km/h. Real-world consumption is typically 10–25% above the WLTP value.
What counts as economical fuel consumption?
Economical is generally considered under 6 L/100 km for petrol and under 5 L/100 km for diesel. Modern compact cars (e.g. VW Polo, Renault Clio) achieve 5–6 L/100 km, compact-class petrol cars typically run 6–8 L/100 km. Larger SUVs and sports cars often exceed 9–12 L/100 km. Electric cars are measured in kWh/100 km and are comparably rated from 12–25 kWh/100 km.
How can I reduce my fuel consumption?
Effective measures: check tire pressure regularly (correct pressure saves up to 0.3 L/100 km), drive with foresight and avoid unnecessary braking, stay under 130 km/h on the highway (consumption rises quadratically with speed), shift up early (for petrol engines from around 2,000 rpm), avoid idling (use engine start-stop), and remove unnecessary weight from the trunk.
Can I also express consumption in km/L or MPG?
In Germany, L/100 km is the standard unit. Our calculator gives the result in L/100 km. Conversion: km/L = 100 ÷ (L/100 km). MPG (miles per gallon, US) can be calculated using the formula 235.21 ÷ (L/100 km). A consumption of 7 L/100 km corresponds to about 14.3 km/L or about 33.6 MPG (US).