There are some errors in your form.

Convert Enter a number here to convert units

Enter the number you wish to convert

metres per cubic metre (m/m³) Kilometres per litre (km/L) miles per gallon (U.K) (mi/gal) miles per gallon (U.S) (mi/gal) Litres per 100km (L/100km)

Choose the units your number is represented in

to metres per cubic metre (m/m³) Kilometres per litre (km/L) miles per gallon (U.K) (mi/gal) miles per gallon (U.S) (mi/gal) Litres per 100km (L/100km)

Choose the units you would like your number to be represented in

=

Precision Enter a number for decimal place precision

For very small numbers or to improve rounding you can set the number of decimal places

Fuel consumption is generally expressed as MPG (Miles Per Gallon) but nowadays the expression litres per 100km (L/100km) is also becoming popular.
The information in the table below provides a method of converting from MPG to the listed expression.

Scheme	Convert to	Multiply MPG by
U.S. gallon	Metres per Cubic meter (m/m³)	425 143.7
U.S. gallon	Kilometre per litre (km/L)	0.425 143 7
U.K. & Canada gallon	Metres per Cubic meter (m/m³)	354 006.2
U.K. & Canada gallon	Kilometre per litre (km/L)	0.354 006 2

To calculate Litres per one hundred kilometres (L/100km) first calculate the Kilometres per Litre (km/L) using the above table then divide 100 by this km/litre value.

For example you have a truck that returns 25mpg (based on U.S. gallons) and you wish to compare that figure with another truck which has a fuel consumption quoted in litres per 100km. 1st calculate the kilometres per litre

km/L = 25 multiplied by 0.425 This equals 10.625 kilometres per litre.

2nd calculate the litres per 100km

L/100km = 100 divided by 10.625 This equals 9.412 litres per 100 kilometres(L/100km)

I recently (2024) did a long journey across Europe starting in Suffolk in the UK and heading over to the East side of Poland. A friend in Germany wanted to understand the economy and they're more familiar with L/100km , so here's a worked example from that journey, maybe it'll help with extra context.

Outbound journey: Citroen Relay DIY camper quite loaded up around 3.2tonnes, tyres 65PSI rear, 59 front. 2.2 Puma Diesel engine 6-speed. Pop-up sun-roof and 1.7x1.1m Solar panel, neither helping the aero qualities which to be fair are brick like anyway.

Starting out in Suffolk early one morning in late September the first leg was 1 hour to Harwich then a 7 hour ferry crossing to Hoek van Hollande, once landed we drove into Germany and parked up for the night. The morning bought the first refuelling of the trip.

19th September 3.2mph headwind (ENE)

20th September 15:07 Trip A 34.7mpg 45mph 512.5mi 11hrs 13mins 2.6mph headwind (Easterly)

trip b same

26th October 14;03 Trip A 35mpg, 43mph, 1111.1mi 25:34mins

26th October 14:03 Trip B 35mpg, 41mph, 598.6mi 14hrs 21mins

26th Otober 14:02 Fuel Pump77.35dm3 498.10zl

4th Nov. Trip B 518mi 15:30 - 32.7mpg 43mph 518.5mi, 12hr:0mins

4th Nov. Trip A 15:30 Arriving somewhere 34.1mpg, 43mph, 1629.7mi, 37h35mins.

7th Nov 16:46 trip A 35.0mpg 44mph, 2241.2mi 50hr 38mins

7th Nov 17:46 trip B 37.2mpg, 46mph, 611.5mi, 13hrs 03mins

Ferry 5th Nov.

TLDR