About the MPG to L/100km Converter
This MPG to L/100km converter translates a fuel-economy figure between the four units used around the world: US miles per gallon, UK (imperial) miles per gallon, litres per 100 kilometres and kilometres per litre. Type one number, pick the unit it is in, and every other unit is calculated at once.
It is useful when you compare a car reviewed in Europe or Australia (L/100km) with one rated in the US (MPG), when you import a vehicle, or when a UK brochure quotes a surprisingly high MPG — imperial gallons are about 20% larger than US gallons, so the same car shows a bigger MPG number in Britain.
Note that MPG and km/L measure distance per fuel (higher is better) while L/100km measures fuel per distance (lower is better). Because one is the reciprocal of the other, the conversion is not linear: improving from 15 to 20 MPG saves far more fuel than improving from 40 to 45 MPG.
With the default inputs, the litres per 100 km is 7.84 L/100km. Change any value above to recalculate instantly.
How to use the mpg to l/100km converter
- 1Type the fuel-economy number you have.
- 2Choose the unit it is expressed in — US MPG, UK MPG, L/100km or km/L.
- 3Read the converted values in every other unit.
- 4Use the reference table to compare several common ratings at a glance.
Formula and method
The converter first turns your figure into kilometres per litre using exact definitions: 1 mile = 1.609344 km, 1 US gallon = 3.785411784 L and 1 imperial gallon = 4.54609 L. From km/L it derives every other unit. L/100km is simply 100 divided by km/L, which is why the constants 235.215 (US) and 282.481 (UK) appear when you go straight from MPG.
Because L/100km is a reciprocal of MPG, doubling MPG halves fuel use, but equal MPG steps do not save equal amounts of fuel. Official ratings (EPA, WLTP) use different test cycles, so converting units does not make a US and a European rating directly comparable.
- MPG(US)
- Miles per US gallon (3.785 L)
- MPG(UK)
- Miles per imperial gallon (4.546 L)
- km/L
- Kilometres travelled per litre
- L/100km
- Litres consumed per 100 km (lower is better)
Worked examples
30 US MPG to L/100km
30 miles per US gallon equals 30 × 1.609344 ÷ 3.785412 = 12.75 km per litre. 100 ÷ 12.75 gives 7.84 L/100km, and the same car would be advertised at about 36.0 MPG in the UK.
6.5 L/100km to MPG
A European hatchback rated at 6.5 L/100km covers 100 ÷ 6.5 = 15.38 km per litre. That is about 36.2 MPG in US gallons or 43.5 MPG in imperial gallons.
50 UK MPG to US MPG
An imperial gallon is 4.546 L versus 3.785 L for a US gallon, so 50 UK MPG shrinks to 41.6 US MPG. In metric terms that is 5.65 L/100km.
Frequently asked questions
How do I convert MPG to L/100km?+
Divide 235.215 by the US MPG figure (or 282.481 by the UK MPG figure). For example, 235.215 ÷ 25 US MPG = 9.41 L/100km.
Why is UK MPG higher than US MPG for the same car?+
The imperial gallon used in the UK holds 4.546 litres, about 20% more than the 3.785-litre US gallon, so a car travels further on one UK gallon and shows a higher MPG figure.
Is a lower L/100km better?+
Yes. L/100km measures how much fuel is used to cover a fixed distance, so a lower number means better economy. MPG and km/L work the other way: higher is better.
What is a good L/100km figure?+
Roughly, under 6 L/100km (about 39 US MPG) is very economical for a petrol car, 7–9 L/100km is typical for compact SUVs and family cars, and above 12 L/100km is thirsty.
How do I convert km/L to MPG?+
Multiply km/L by 2.352 to get US MPG, or by 2.825 to get UK MPG. For example, 15 km/L is about 35.3 US MPG.