mpg to L/100 km
Mile per gallon (US) and Liter per 100 km run in opposite directions, so a lower figure in one means a higher figure in the other.
Converter
Mile per gallon (US) to Liter per 100 km at a glance
21 rows| Mile per gallon (US) | Liter per 100 km |
|---|---|
| 1 mpg | 235.2145833 L/100km |
| 2 mpg | 117.6072917 L/100km |
| 3 mpg | 78.40486111 L/100km |
| 4 mpg | 58.80364583 L/100km |
| 5 mpg | 47.04291667 L/100km |
| 6 mpg | 39.20243056 L/100km |
| 7 mpg | 33.60208333 L/100km |
| 8 mpg | 29.40182292 L/100km |
| 9 mpg | 26.1349537 L/100km |
| 10 mpg | 23.52145833 L/100km |
| 15 mpg | 15.68097222 L/100km |
| 20 mpg | 11.76072917 L/100km |
| 25 mpg | 9.408583333 L/100km |
| 30 mpg | 7.840486111 L/100km |
| 40 mpg | 5.880364583 L/100km |
| 50 mpg | 4.704291667 L/100km |
| 75 mpg | 3.136194444 L/100km |
| 100 mpg | 2.352145833 L/100km |
| 250 mpg | 0.9408583333 L/100km |
| 500 mpg | 0.4704291667 L/100km |
| 1,000 mpg | 0.2352145833 L/100km |
Quick pairs
tap to loadWhy people convert mpg to l/100 km
Cross-shopping a car sold in both the US and a metric fuel-economy market means converting between miles per gallon and liters per 100 kilometers, two figures that do not scale the same way since one is a rate and the other a consumption figure. A car rated at 30 mpg works out to roughly 7.8 L/100km, and, confusingly, a lower L/100km figure is better while a higher mpg figure is better, the reverse of each other.
Renting a car for a road trip in Europe is the other common trigger: the rental company's fuel economy sticker and every roadside price sign reads in L/100km, while a US traveler is mentally budgeting in miles per gallon from home, so converting the sticker figure is the only way to sanity-check how much the trip will actually cost in fuel.
How the mile per gallon (us) to liter per 100 km conversion works
Mile per gallon (US) and liter per 100 km measure fuel economy in opposite directions: mpg is distance per unit of fuel, while L/100km is fuel per unit of distance, so the two are reciprocals of each other rather than a simple multiply-by-a-constant pair.
The constant that links them is 235.214583, derived from the US gallon and the kilometer: L/100km = 235.214583 ÷ mpg.
A 30 mpg sedan converts to 235.214583 ÷ 30 = 7.84 L/100km. A 50 mpg hybrid converts to 235.214583 ÷ 50 = 4.70 L/100km. A 15 mpg heavy pickup truck converts to 235.214583 ÷ 15 = 15.68 L/100km.
Because the formula is self-inverse, converting back uses the exact same constant: mpg = 235.214583 ÷ (L/100km). A car rated at 7.84 L/100km converts back to 235.214583 ÷ 7.84 ≈ 30 mpg, confirming the round trip (the tiny difference from exactly 30 is just rounding of the 7.84 figure itself).
Rounding matters more here than in a linear conversion, since the result changes unevenly across the range: at low mpg values a one-unit change in mpg shifts L/100km by a large amount, while at high mpg values the same one-unit change barely moves the L/100km figure at all, so always keep at least two decimal places when comparing fuel-efficient cars.
The mistake specific to this pair is treating it like a normal linear conversion and multiplying by a fixed factor. Because mpg and L/100km are reciprocals, you cannot average them directly either: averaging the mpg of a 20 mpg and a 60 mpg trip does not give the same answer as averaging the equivalent L/100km figures and converting back, since the relationship between the two scales isn't linear.
Questions
How many liters per 100 km does a 40 mpg car use?
235.214583 ÷ 40 = 5.88 L/100km.
How do I convert liters per 100 km back to miles per gallon?
Use the same constant in the same way: divide 235.214583 by the L/100km figure. A car rated at 6 L/100km, for example, converts back to 235.214583 ÷ 6 ≈ 39.2 mpg.
Why do the US and most other countries measure fuel economy so differently?
The US reports fuel economy as a rate — how far a gallon takes you — while most metric countries report it as consumption — how much fuel a fixed distance uses. Both describe the same physical efficiency, just answering a different practical question ("how far can I go" versus "how much will this trip cost").
Is there a quick way to estimate L/100km from mpg without the exact formula?
Divide 235 by the mpg figure for a close estimate. It won't be exact to the decimal, but it's accurate enough for comparing two cars at a glance.
What's the most common mistake when converting between mpg and L/100km?
Multiplying by a fixed factor as if the relationship were linear, and forgetting the two scales are reciprocals — which also means you can't just average mpg figures across a fleet or a trip and expect the same result as averaging the equivalent L/100km figures.
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