Fuel Consumption CalculatorL/100 km Calculator & MPG Converter
L/100 km = litres used ÷ kilometres driven × 100.
Calculate your fuel consumption in litres per 100 km from a fill-up, or convert any figure between L/100 km, km per litre, US MPG and UK MPG. Built for drivers in the UK, Canada, Australia, Europe and anyone comparing cars across markets.
Your numbers
39.00 litres over 520 km.
EfficientWhere you sit (L/100 km — lower is better)
How do you calculate fuel consumption in L/100 km?
L/100 km = litres used ÷ kilometres driven × 100. Fill the tank, drive, refill, and divide the litres it took by the distance, then multiply by 100. 520 km on 39 litres is 7.50 L/100 km — about 13.3 km per litre, 31.4 US MPG or 37.7 UK MPG. Unlike MPG, a lower L/100 km figure means better economy.
Part of our Fuel, Mileage & Trip Cost calculators — for the core estimate, start with the Fuel Cost Calculator.
How to measure fuel consumption
Fill to the brim
Fill until the pump clicks off and reset your trip meter.
Drive as usual
Use at least half a tank in normal conditions.
Refill and record
Note the litres it takes to fill up again and the kilometres on the trip meter.
Enter both numbers
The calculator gives L/100 km and converts it to km/L, US MPG and UK MPG.
Fuel consumption conversion formulas
km per litre = km ÷ litres = 100 ÷ (L/100 km)
US MPG = 235.215 ÷ (L/100 km)
UK MPG = 282.481 ÷ (L/100 km)
UK MPG = US MPG × 1.20095
The two MPG figures differ because a UK (imperial) gallon is 4.546 litres while a US gallon is 3.785 litres. A car that does 40 MPG in the UK does about 33 MPG by the US measure — same car, same fuel use.
Working in US units? The Gas Mileage Calculator measures MPG from a fill-up, and the Fuel Cost Calculator turns either figure into a trip cost.
L/100 km to MPG conversion chart
| L/100 km | km per litre | US MPG | UK MPG |
|---|---|---|---|
| 4 | 25.00 | 58.8 | 70.6 |
| 5 | 20.00 | 47.0 | 56.5 |
| 6 | 16.67 | 39.2 | 47.1 |
| 7 | 14.29 | 33.6 | 40.4 |
| 8 | 12.50 | 29.4 | 35.3 |
| 9 | 11.11 | 26.1 | 31.4 |
| 10 | 10.00 | 23.5 | 28.2 |
| 11 | 9.09 | 21.4 | 25.7 |
| 12 | 8.33 | 19.6 | 23.5 |
| 14 | 7.14 | 16.8 | 20.2 |
| 16 | 6.25 | 14.7 | 17.7 |
Why L/100 km is easier to compare than MPG
L/100 km measures fuel used for a fixed distance, so savings add up in a straight line. Going from 10 to 8 L/100 km saves 2 litres every 100 km — exactly the same as going from 6 to 4. With MPG the scale is curved: the jump from 15 to 20 MPG saves more fuel than the jump from 40 to 50 MPG, which often surprises people.
Comparing with an electric car? The EV Charging Cost Calculator shows kWh and cost per 100 km.
Example: 520 km on 39 litres
39 ÷ 520 × 100 = 7.50 L/100 km. That’s 100 ÷ 7.5 = 13.33 km/L, 235.215 ÷ 7.5 = 31.4 US MPG and 282.481 ÷ 7.5 = 37.7 UK MPG. These are the calculator’s default numbers.
Related calculators
Fuel Consumption Calculator FAQs
Divide the litres used by the kilometres driven and multiply by 100. For example, 39 litres over 520 km is 39 ÷ 520 × 100 = 7.5 L/100 km.
For US MPG, divide 235.215 by the L/100 km figure. For UK MPG, divide 282.481 by it. 7.5 L/100 km is 31.4 US MPG or 37.7 UK MPG.
Divide 235.215 by US MPG, or 282.481 by UK MPG. 30 US MPG is 7.84 L/100 km.
Under about 6 L/100 km is very economical for a petrol car, 7 to 9 is typical for midsize cars and crossovers, and large SUVs and pickups often use 11 or more. Hybrids can go below 5.
Yes. L/100 km measures fuel used per distance, so a lower number means you use less fuel.
A UK imperial gallon is about 4.546 litres and a US gallon is about 3.785 litres. The same car shows roughly 20% higher MPG in UK gallons.
Divide 100 by the km per litre figure. 15 km/L is 100 ÷ 15 = 6.67 L/100 km.
About 39.2 US MPG or 47.1 UK MPG.
About the developer
Manzoor Ahmad
Web Designer & Calculator Developer · 13+ years of web development and SEO experienceI’m a professional pharmacist turned tech geek, and I designed and coded this fuel consumption calculator myself. The conversion constants come from the exact litre, US gallon and imperial gallon definitions, and the chart on this page is generated from the same formulas the calculator uses.
Found a number that looks wrong, or want a feature added? Tell me through my author page — corrections are fixed and re-dated.
Sources
- Natural Resources Canada — Fuel Consumption Guide
- U.S. DOE & EPA — FuelEconomy.gov
- NIST — Units of measurement: gallon definitions (Handbook 44, Appendix C)
Disclaimer: Conversions are exact to the stated precision. Measured fuel consumption depends on driving conditions, and pump fill levels vary slightly between fill-ups.
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