MPG to L/100km Calculator
Convert between MPG and litres per 100km.
Reviewed by the Calculation Machine team · Updated 24 October 2026 · How we check our maths
Your values
ⓘ Live results
- Litres per 100 km
- 7.35
- Imperial MPG
- 38.43
- Km per litre
- 13.6
- US MPG entered
- 32
Quick answer
To convert US miles per gallon to liters per 100 km, divide 235.215 by the mpg figure. For UK (imperial) mpg, divide 282.481 by the mpg instead. The same formula works in reverse: divide 235.215 by L/100 km to get US mpg. A car rated at 32 US mpg uses 7.35 L/100 km, which is about 38.4 mpg in imperial gallons.
What the MPG to L/100km calculator does
This converter takes a fuel-economy figure in US miles per gallon and gives the equivalent in liters per 100 kilometers, imperial (UK) mpg and kilometers per liter. It is for comparing a US-market car with European, Canadian or Australian figures, reading a foreign car review, or understanding your own car's economy in a different unit.
The two systems run in opposite directions. MPG measures distance per unit of fuel, so higher is better. L/100 km measures fuel per unit of distance, so lower is better. That inversion is why the conversion is a division, not a multiplication.
If you don't yet know your car's real mpg, work it out from your fill-ups with the MPG calculator first. To turn either figure into money, use the fuel cost calculator.
The formula
L/100 km = 235.215 ÷ US MPG US MPG = 235.215 ÷ L/100 km Imperial MPG = US MPG × 1.20095 km/L = 100 ÷ (L/100 km)
| Symbol | Meaning | Unit |
|---|---|---|
| US MPG | Miles per US gallon (3.78541 L) | mi/gal |
| L/100 km | Liters of fuel used to travel 100 kilometers | L/100 km |
| 235.215 | 100 × 3.78541 L per US gallon ÷ 1.609344 km per mile | — |
| 1.20095 | Imperial gallon (4.54609 L) ÷ US gallon (3.78541 L) | — |
The constants come from the exact legal definitions of the mile (1.609344 km), the US gallon (231 cubic inches, 3.785411784 L) and the imperial gallon (4.54609 L). For imperial mpg, the equivalent constant is 282.481. Because the formula is a reciprocal, the same constant converts in both directions.
Worked examples
US-market sedan
A sedan with an EPA combined rating of 32 mpg, compared with a European rival listed in L/100 km.
Inputs
- Fuel economy32 US MPG
Result
- Litres per 100 km7.35
- Imperial MPG38.43
- Km per litre13.6
- US MPG entered32
32 US mpg is 7.35 L/100 km. Keep in mind that EPA and European (WLTP) test cycles differ, so a converted figure is not a like-for-like test result.
Hybrid hatchback
A hybrid rated at 52 US mpg.
Inputs
- Fuel economy52 US MPG
Result
- Litres per 100 km4.52
- Imperial MPG62.45
- Km per litre22.11
- US MPG entered52
About 4.5 L/100 km, or 62.5 mpg in UK terms. UK readers will see the higher imperial number in British reviews for the same car.
Large SUV
A three-row SUV that averages 18 US mpg.
Inputs
- Fuel economy18 US MPG
Result
- Litres per 100 km13.07
- Imperial MPG21.62
- Km per litre7.65
- US MPG entered18
About 13.1 L/100 km. At this end of the scale, each extra mpg saves far more fuel than it does on an efficient car, which the L/100 km figure makes obvious.
MPG to L/100 km conversion table
Values rounded; imperial mpg is the US figure × 1.20095.
| US mpg | L/100 km | UK (imperial) mpg |
|---|---|---|
| 15 | 15.68 | 18.0 |
| 20 | 11.76 | 24.0 |
| 25 | 9.41 | 30.0 |
| 30 | 7.84 | 36.0 |
| 35 | 6.72 | 42.0 |
| 40 | 5.88 | 48.0 |
| 50 | 4.70 | 60.0 |
| 60 | 3.92 | 72.1 |
Converting L/100 km back to mpg
Divide 235.215 by the L/100 km figure for US mpg, or 282.481 for UK mpg.
- 5 L/100 km = 47.0 US mpg = 56.5 UK mpg
- 6 L/100 km = 39.2 US mpg = 47.1 UK mpg
- 8 L/100 km = 29.4 US mpg = 35.3 UK mpg
- 10 L/100 km = 23.5 US mpg = 28.2 UK mpg
If you have an imperial mpg figure, divide it by 1.20095 first, then enter the result here as US mpg.
Why L/100 km shows fuel savings more honestly
Because mpg is distance per gallon, equal mpg gains do not save equal fuel. Over 100 miles, going from 10 to 20 mpg cuts fuel use from 10 gallons to 5, saving 5 gallons. Going from 30 to 50 mpg cuts it from 3.33 to 2 gallons, saving only 1.33.
Researchers call this the "MPG illusion". Fuel-per-distance units such as L/100 km, or the gallons-per-100-miles figure now printed on US window stickers, scale directly with fuel used and cost, so they make comparisons easier. The EV vs gas cost calculator applies the same idea to electric cars.
How to use the MPG to L/100km Calculator
- 1Enter fuel economy in US miles per gallon, from an EPA sticker, a US review or your own fill-up records.
- 2If your figure is imperial (UK) mpg, divide it by 1.20095 before entering it.
- 3Read liters per 100 km; lower numbers mean less fuel used.
- 4Use the imperial mpg and km per liter outputs to compare with UK, Asian or Latin American sources.
Frequently asked questions
How do you convert mpg to L/100 km?
Divide 235.215 by the US mpg figure. For example, 25 mpg is 235.215 ÷ 25 = 9.41 L/100 km.
What is 7 L/100 km in mpg?
About 33.6 US mpg or 40.4 UK mpg. Divide 235.215 (US) or 282.481 (UK) by 7.
Why is UK mpg higher than US mpg for the same car?
The imperial gallon is 4.546 liters and the US gallon is 3.785 liters, so a UK gallon is about 20% bigger and takes you about 20% further.
Is a lower L/100 km better?
Yes. L/100 km is the fuel used per distance, so a car using 5 L/100 km is more economical than one using 8 L/100 km.
Which countries use L/100 km?
Most of Europe, Canada, Australia and China quote fuel consumption in L/100 km. The US uses miles per US gallon, and the UK still uses miles per imperial gallon.
References
- NIST Handbook 44, Appendix C – General Tables of Units of Measurement — National Institute of Standards and Technology
- The MPG Illusion (Larrick & Soll, Science, 2008) — American Association for the Advancement of Science
- Fuel Economy Guide — US Department of Energy and US Environmental Protection Agency (fueleconomy.gov)
About this calculator
- Built and reviewed by the Calculation Machine team · How we build and test calculators
- Last reviewed: October 24, 2026
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