Convert km/L to L/100km
Kilometres per litre and litres per 100 km are the same measurement inverted. km/L counts distance per unit of fuel; L/100km counts fuel per unit of distance. So the conversion is a division, not a multiplication: L/100km = 100 ÷ km/L. Both units are metric, which makes this the cleanest fuel-economy conversion there is — no gallon to disambiguate, and a constant that is simply the 100 in the unit’s own name.
To convert km/L to L/100km, divide 100 by the km/L figure. So 12 km/L = 100 ÷ 12 = 8.33 L/100km. The same formula runs backwards: km/L = 100 ÷ L/100km. At exactly 10, the two units give the same number.
L/100km = 100 ÷ km/L, and equally km/L = 100 ÷ L/100km. There is only one formula because a reciprocal relationship is its own inverse. Nothing is derived or approximated: a car covering 10 km on one litre uses one litre per 10 km, which is 10 litres per 100 km. The 100 is the hundred kilometres the unit is defined over.
| km/L | 100 ÷ km/L | L/100km |
|---|---|---|
| 5 km/L | 100 ÷ 5 | 20 L/100km |
| 10 km/L | 100 ÷ 10 | 10 L/100km |
| 15 km/L | 100 ÷ 15 | 6.667 L/100km |
| 20 km/L | 100 ÷ 20 | 5 L/100km |
How to convert km/L to L/100km
Divide 100 by the figure you have. That works in both directions, because inverting twice returns you to the start: 12 km/L gives 100 ÷ 12 = 8.333 L/100km, and 100 ÷ 8.333 gives 12 km/L again. The swap button on the converter above therefore changes only the labels — the arithmetic is identical either way.
Note which way the scale runs. Higher km/L is better — more distance from the same fuel. Lower L/100km is better — less fuel for the same distance. Reversing that is the single most common error when reading across the two units, and because the numbers overlap in the same range for ordinary cars, a mistaken figure will not look obviously wrong.
Because 100 ÷ 10 = 10, a vehicle at 10 km/L is also at exactly 10 L/100km. It is the one value where both units agree, and it is a useful landmark: above 10 km/L the L/100km figure is the smaller of the two, below it the larger. The converter opens on this value for that reason — both boxes read 10, which shows at a glance that this is a reciprocal and not a scaling.
km/L to L/100km conversion table
The table reads both ways: because the relation is its own inverse, either column can be the input. A row saying 8 and 12.5 means 8 km/L is 12.5 L/100km and 8 L/100km is 12.5 km/L.
| km/L | L/100km | Reads both ways |
|---|---|---|
| 4 | 25 | 4 ↔ 25 |
| 5 | 20 | 5 ↔ 20 |
| 6 | 16.67 | 6 ↔ 16.67 |
| 8 | 12.5 | 8 ↔ 12.5 |
| 10 | 10 | 10 ↔ 10 |
| 12 | 8.333 | 12 ↔ 8.333 |
| 15 | 6.667 | 15 ↔ 6.667 |
| 20 | 5 | 20 ↔ 5 |
| 25 | 4 | 25 ↔ 4 |
| 30 | 3.333 | 30 ↔ 3.333 |
km/L compared with MPG
km/L and miles per gallon are the same idea in different units — both count distance per unit of fuel — so converting between them is a straightforward multiplication, unlike the reciprocal step to L/100km.
| km/L | L/100km | MPG (US) | MPG (UK) |
|---|---|---|---|
| 5 | 20 | 11.76 | 14.12 |
| 8 | 12.5 | 18.82 | 22.60 |
| 10 | 10 | 23.52 | 28.25 |
| 15 | 6.667 | 35.28 | 42.37 |
| 20 | 5 | 47.04 | 56.50 |
| 25 | 4 | 58.80 | 70.62 |
The multipliers are 1 km/L = 2.3521 mpg (US) = 2.8248 mpg (UK) — the same 235.215 and 282.481 constants the MPG to L/100km converter uses, divided by a hundred. Whether that page’s US/UK toggle matters to you depends entirely on your source, which brings up this unit’s quiet advantage.
A “48 mpg” figure is ambiguous: the imperial gallon is about 20% larger than the US one, so British and American sources describe different cars with the same number, and neither usually says which it means. km/L has no such variant. A litre is a litre and a kilometre is a kilometre in every country that uses them, so a km/L figure travels without a footnote. That is why this converter has no unit toggle where the MPG one needs a prominent one.
km/L inherits the MPG illusion
Because km/L is distance-per-fuel, it shares MPG’s most important flaw: equal steps do not represent equal fuel savings. Fuel used is proportional to 1 ÷ km/L, so an improvement at the bottom of the scale saves far more than the same improvement higher up.
Going from 5 to 6 km/L cuts consumption from 20 to 16.67 L/100km — a saving of 3.33 litres every hundred kilometres. Going from 20 to 21 km/L, the same one-unit step, cuts consumption from 5 to 4.76 — a saving of 0.24 litres, about fourteen times less. The MPG converter sets this out in full, including the research that named it; the point transfers directly, because the two units differ only by a constant.
Tailpipe CO₂ is proportional to fuel burned, not to distance covered per litre. So L/100km is the unit that tracks emissions linearly and km/L is not: a 10% improvement in km/L does not cut emissions by 10%. If you are comparing vehicles on carbon rather than on range, convert to L/100km first and compare there — or compare gCO₂/km, which is L/100km scaled by a fuel-specific factor.
Where km/L is used
- Japan — the standard consumer figure, quoted under the WLTC test cycle.
- India — the everyday measure of a car’s efficiency, usually called “mileage” locally.
- Brazil and much of Latin America, where it also has to be read against ethanol blends that carry less energy per litre than petrol.
- Parts of the Middle East, South-East Asia and Africa — anywhere fuel is sold in litres but distance-per-fuel is the intuitive framing.
Europe standardised on L/100km, and it is the basis of EU CO₂ regulation for exactly the reason set out above: it is linear in the quantity that produces emissions. The United States and the United Kingdom use miles per gallon, with different gallons.
Fuel consumption is one step from tailpipe CO₂ — burning a litre releases a fixed mass of carbon dioxide, so gCO₂/km is L/100km times a fuel-specific factor. This page stops at the unit conversion. For the emissions side see kg CO₂e per litre to per gallon and g CO₂e/km to /mile, with DEFRA for the factors themselves. For a full vehicle footprint including manufacturing, that is a calculator — see the EV vs petrol lifecycle calculator.
Frequently Asked Questions
Divide 100 by the km/L figure. For example, 12 km/L = 100 ÷ 12 = 8.33 L/100km. It is a division rather than a multiplication because the two units are reciprocals — one measures distance per litre, the other litres per distance.
The same division: km/L = 100 ÷ L/100km. A reciprocal relationship is its own inverse, so there is only one formula. 8.333 L/100km gives 100 ÷ 8.333 = 12 km/L.
Because both units are metric, so no gallon and no mile enters the calculation. A car covering 10 km on one litre uses one litre per 10 km, which is 10 litres per 100 km. The 100 is simply the hundred kilometres the unit is defined over — this is the only fuel-economy conversion with nothing to derive.
Yes — 10. Since 100 ÷ 10 = 10, a vehicle at 10 km/L is also at exactly 10 L/100km. It is the only such value, and a handy landmark: above 10 km/L the L/100km number is smaller, below it the number is larger.
Higher km/L is better, because you travel further on the same fuel. Lower L/100km is better, because you use less fuel over the same distance. The two run in opposite directions, and since ordinary cars produce numbers in a similar range in both units, a figure read the wrong way round will not look obviously wrong.
Both count distance per unit of fuel, so converting between them is a simple multiplication: 1 km/L = 2.3521 mpg (US) = 2.8248 mpg (UK). km/L has one clear advantage — there is no ambiguity about the unit, whereas an mpg figure means different things depending on whether the gallon is American or imperial, roughly a 20% difference, and sources rarely say which.
L/100km, if the question is fuel or emissions. Because km/L is distance-per-fuel, equal steps in it are not equal savings: 5 to 6 km/L saves 3.33 litres per 100 km, while 20 to 21 km/L — the same one-unit step — saves only 0.24, about fourteen times less. Tailpipe CO₂ is proportional to fuel burned, so L/100km tracks emissions linearly and km/L does not.