MPG to Liters per 100 km (mpg to L/100km)
L/100km = 235.215 ÷ mpg (US)
| miles per gallon (US) | liters per 100 km |
|---|---|
| 15 mpg (US) | 15.68 L/100km |
| 18 mpg (US) | 13.07 L/100km |
| 20 mpg (US) | 11.76 L/100km |
| 22 mpg (US) | 10.69 L/100km |
| 25 mpg (US) | 9.409 L/100km |
| 30 mpg (US) | 7.84 L/100km |
| 35 mpg (US) | 6.72 L/100km |
| 40 mpg (US) | 5.88 L/100km |
| 50 mpg (US) | 4.704 L/100km |
| 60 mpg (US) | 3.92 L/100km |
UK (imperial) mpg: L/100km = 282.481 ÷ mpg, so 40 UK mpg = 7.06 L/100km and 50 UK mpg = 5.65 L/100km.
Litres per 100 km and miles per gallon are reciprocals, so you divide rather than multiply: L/100km = 235.215 ÷ US mpg. The constant is 100 × 3.785411784 L per US gallon ÷ 1.609344 km per mile — both exact definitions (NIST SP 811 Appendix B).
Formula
L/100km = 235.215 ÷ mpg (US)
Example: 17 miles per gallon (US) = 13.8362 liters per 100 km.
MPG to Liters per 100 km chart
| miles per gallon (US) | liters per 100 km |
|---|---|
| 10 | 23.5215 |
| 12 | 19.6012 |
| 15 | 15.681 |
| 17 | 13.8362 |
| 18 | 13.0675 |
| 20 | 11.7607 |
| 22 | 10.6916 |
| 24 | 9.80061 |
| 25 | 9.40858 |
| 28 | 8.40052 |
| 30 | 7.84049 |
| 32 | 7.35046 |
| 35 | 6.72042 |
| 38 | 6.18986 |
| 40 | 5.88036 |
| 45 | 5.22699 |
| 50 | 4.70429 |
| 55 | 4.27663 |
| 60 | 3.92024 |
Good to know
Lower is better in L/100km. mpg measures distance per fuel; L/100km measures fuel per distance. A car going from 20 to 25 mpg saves 2.35 L every 100 km, while going from 40 to 50 mpg saves only 1.18 L — which is why fuel-per-distance figures make savings easier to compare.
UK and US gallons differ. An imperial gallon is 4.54609 L and a US gallon 3.785411784 L, so for UK mpg use 282.481 ÷ mpg. A car rated 40 mpg in the UK uses 7.06 L/100km; 40 US mpg is 5.88 L/100km. Always check which gallon a figure uses before comparing.
Mental check: 235 ÷ mpg. 30 mpg is about 7.8, 20 mpg about 11.8, 47 mpg about 5. For km per litre, divide 100 by the L/100km figure, or use our fuel economy converter, which handles US mpg, UK mpg, L/100km and km/L together.
Frequently asked questions
How do you convert mpg to L/100km?
Divide 235.215 by the US mpg figure. 30 mpg → 235.215 ÷ 30 = 7.84 L/100km.
What is 30 mpg in L/100km?
30 US mpg is 7.84 L/100km (UK 30 mpg is 9.42 L/100km).
What is 25 mpg in L/100km?
25 US mpg is 9.41 L/100km.
What is 20 mpg in L/100km?
20 US mpg is 11.76 L/100km.
What is 40 mpg in L/100km?
40 US mpg is 5.88 L/100km.
Why does the number go down as mpg goes up?
L/100km is fuel used per distance, the inverse of mpg's distance per fuel. More miles per gallon means fewer litres per 100 km.