Convert km/L to L/100km kilometres per litre ↔ litres per 100 kilometres Free Online Secure
Type a figure in kilometres per litre and read it in litres per 100 kilometres at once. These two run opposite ways — one counts fuel per distance, the other distance per fuel — so the page divides rather than multiplies.
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Convert to litres per 100 kilometres
Common values — Convert km/L to L/100km (kilometres per litre ↔ litres per 100 kilometres)
| km/L | L/100km |
|---|---|
| 5 | 20 |
| 8 | 12.5 |
| 10 | 10 |
| 12 | 8.33333333333 |
| 15 | 6.66666666667 |
| 18 | 5.55555555556 |
| 20 | 5 |
| 25 | 4 |
Where these units come from
Fuel economy is said in two opposite ways. Litres per 100 km asks how much fuel a fixed distance costs; miles per gallon and kilometres per litre ask how far a fixed amount of fuel goes. One is the reciprocal of the other, which is why this page multiplies and divides rather than scaling. Europe settled on litres per 100 km in the 1970s precisely because it is linear in the thing you actually pay for: halve the number and you halve the fuel. The United States kept miles per gallon, and Britain kept it too but with the imperial gallon — a fifth larger — so the same car scores about 20% better in British figures than in American ones without a single part having changed.
Where you meet them
These numbers decide which car gets bought, what a fleet costs to run, how company-car tax is assessed in several countries, and whether a long trip is worth driving rather than flying. They also appear on every new-car window sticker, measured on a standard test cycle rather than on a real road — which is why the figure is best used to compare one car with another, not to predict what your own week will cost.
Questions people ask
Why does the same car get a better mpg figure in Britain than in America?
Because the gallons are different. The imperial gallon is 4.54609 litres and the US gallon 3.785411784 litres, about a fifth smaller. A car that travels 30 miles on a US gallon travels the same distance on less than a British gallon, so its British figure comes out around 36 mpg. Nothing about the car changed; only the size of the container did. Always check which gallon a figure means before comparing two cars across the Atlantic.
Why is litres per 100 km considered the better measure?
Because miles per gallon flatters improvements at the top and hides them at the bottom. Going from 10 to 15 mpg saves twice as much fuel over the same distance as going from 30 to 50 — which is the opposite of what the numbers look like. Litres per 100 km has no such trap: the saving is simply the difference between the two figures. This is why fuel-saving decisions are easier to judge in litres per 100 km, even where mpg is what everyone quotes.
Is the answer exact?
Where both units are defined in terms of one another by whole numbers, yes — the page says so above the figure, and the only rounding is in how many digits are shown. Where the ratio has no finite decimal, the page shows twelve significant digits and says the relation is approximate rather than pretending otherwise.
Does anything I type leave my device?
No. The arithmetic runs in your browser; nothing is uploaded and there is no server to upload it to. Load the page once and it keeps working with the network switched off.
km/L to L/100 km: reading Japanese fuel economy and kei car data
Japan counts fuel economy in kilometres per litre, and the word for it, nenpi, appears on every brochure, auction sheet and dashboard. A kei car is advertised at 25 km/L, a hybrid minivan at 20, a sports coupe at 11. Visitors, importers and anyone reading a Japanese review for a car sold elsewhere have to turn those figures into the litres per 100 km that European, Canadian and Australian labels use. To convert km/L to L/100km, divide 100 by the figure: 25 km/L is 4 L/100 km, 20 km/L is 5 L/100 km, 11 km/L is 9.09 L/100 km and 8 km/L is 12.5 L/100 km. The calculator above divides as you type, and the sections that follow show what the numbers mean in Japan's test cycles, taxes and traffic.
Below come the rule with examples, short notes on each unit, a side-by-side look and a long series of Japanese motoring cases, ending with the slips people make most. Everything is computed locally in the page. Laboratory figures are always better than real driving, and Japan's older cycle was especially generous.
How to convert km/L to L/100km: divide 100 by the figure
The rule
A car that goes x kilometres on a litre needs 100 / x litres for 100 km. For a “convert km/L to L/100km” calculation, take the km/L figure and divide 100 by it: 100 / 16 = 6.25 L/100 km, 100 / 23.5 = 4.26 L/100 km and 100 / 9 = 11.1 L/100 km. The same division turns L/100 km back into km/L, since the two are reciprocals and their product is always 100.
Better means higher, and lower
A larger km/L is a more economical car, while a smaller L/100 km is. From 10 to 20 km/L consumption falls from 10 to 5 L/100 km. From 20 to 40 it falls from 5 to 2.5. The gains in litres shrink as km/L rises, so a jump from 10 to 15 km/L saves more fuel than a jump from 30 to 35.
Worked examples
A kei car at 21.2 km/L uses 4.72 L/100 km. A compact hybrid at 28.6 km/L uses 3.50. A hybrid minivan at 18.4 km/L uses 5.43, and a large luxury saloon at 9.6 km/L uses 10.4 L/100 km.
A quick sanity test
Expect the two figures to multiply to 100: 21.2 times 4.72 gives 100.1. A product far from that means the “convert km/L to L/100km” calculation went wrong, perhaps by dividing the wrong way round.
Kilometres per litre
The Japanese measure
Distance per litre is the unit of Japanese labels, brochures and trip computers. A larger number is better. Korea, Taiwan and Hong Kong use the same unit, and many Japanese-market features, such as eco-tax thresholds, are tied to it.
Where it appears
Japanese brochures, auction sheets, dashboards and tax and incentive rules.
Litres per 100 kilometres
The measure of Europe
Fuel per distance is the unit on European type approvals, Canadian labels and Australian guides. A smaller number is better, and the cost of a trip is the consumption times the price per litre.
Where it appears
European data sheets, cost calculators and fleet reports.
km/L set beside L/100 km
Seen in litres per 100 km, a Japanese figure runs the opposite way: 10 km/L becomes 10, 25 km/L becomes 4 and 50 km/L becomes 2, and the product of each pair stays at 100. A high km/L corresponds to a low consumption in litres.
Nothing is lost on the way. The mistake that shows up most is multiplying where a division is needed, which would put 25 km/L at 2,500 L/100 km.
Where the conversion shows up
Japan's test cycles
Japan's old JC08 cycle was gentle and gave high figures. A hybrid labelled 30 km/L under JC08, 3.33 L/100 km, may be 24 km/L, 4.17 L/100 km, under the newer WLTC cycle, which Japan adopted in 2018. The WLTC figure is closer to the European label, so when you convert km/L to L/100km for an older auction sheet, allow a margin of 15 to 25 per cent.
Kei cars
Kei cars have engines of no more than 660 cc and a power limit of 64 PS. Their WLTC consumption is 18 to 25 km/L, 4.0 to 5.6 L/100 km, which is about the same as a good European supermini. The advantage of the class is tax, parking and light weight, not exceptional economy.
Hybrids and minivans
A Japanese compact hybrid reaches 25 to 35 km/L under WLTC, 2.9 to 4.0 L/100 km, a hybrid minivan 17 to 21, 4.8 to 5.9, and a petrol minivan 11 to 14, 7.1 to 9.1. Weight and body shape separate them far more than engine size.
The fuel economy standard
Japan's fuel economy rules for new cars have used a "top runner" system, in which the best vehicle in each weight class sets the standard. The target for 2030 is about 25.4 km/L, 3.94 L/100 km, on the WLTC cycle, as a fleet average. Manufacturers meet it with hybrids and small engines.
Mild hybrids and idling stop
Most new Japanese cars have a start-stop system that turns the engine off at the lights, and many have a mild-hybrid assist. Together they can improve town consumption by 5 to 12 per cent, from 15 km/L, 6.67 L/100 km, to 16 to 17 km/L, 5.9 to 6.3 L/100 km. On the motorway the benefit is small.
A worked example
You are comparing a Japanese hybrid labelled 27 km/L on the WLTC with a European one labelled 4.1 L/100 km. The first is 3.70 L/100 km, the second 24.4 km/L. Over 12,000 km the Japanese car uses 444 litres and the European one 492, a difference of 48 litres. If the Japanese figure were JC08, it should be cut by 20 per cent, to 21.6 km/L, which flips the result.
The mental shortcut
To convert km/L to L/100km without a calculator, simply divide 100 by the figure. Easy cases are 4 giving 25, 5 giving 20, 8 giving 12.5, 10 giving 10 and 20 giving 5. For 14, work out 100 / 14 = 7.14. The method is exact.
Spreadsheet formulas
Put the km/L in column A, then =100/A2 in column B returns L/100 km, and the same formula works in reverse. =A2*2.352146 gives US mpg and =A2*2.824809 imperial mpg for cross-checks.
Rounding on brochures
Brochures print km/L to one decimal place, so two decimals of L/100 km are enough: 24.2 km/L is 4.13. A third decimal would be noise, since cycle results are reliable to about 3 to 5 per cent.
Landmarks to memorise
Remember that 6 km/L = 16.7 L/100 km, 8 = 12.5, 10 = 10, 12.5 = 8, 16.7 = 6, 20 = 5, 25 = 4 and 33.3 = 3. With them a mental convert km/L to L/100km takes a moment.
Reference ladder
5.5 km/L: 18.2 L/100 km. 9.5: 10.5. 13: 7.69. 18: 5.56. 24: 4.17. 31: 3.23. 48: 2.08. With a list of this kind any result can be checked quickly.
Checking by reversing
Test a “convert km/L to L/100km” calculation answer by dividing 100 by it: 5.56 L/100 km gives 18.0 km/L, so the 18 you started from came through intact. A second sign of a good result is that the product of the two numbers is 100.
Link to mpg
In 20 km/L there are 5 L/100 km, 47.0 US mpg and 56.5 imperial mpg. Multiply km/L by 2.352 for US mpg and by 2.825 for imperial. The units differ and the consumption does not, so a “convert km/L to L/100km” calculation only relabels it.
Two routes to one answer
Go straight with 100 divided by the km/L, or travel via US mpg: km/L × 2.352, then 235.215 ÷ that. If the answers drift apart, a digit slipped somewhere.
Eco-car tax breaks
Japan gives tax reductions on cars that beat the standard by set margins. A car that is 20 per cent better than the fuel economy target pays less tax at purchase and in the first years of ownership. A target of 20 km/L, 5 L/100 km, becomes 24 km/L, 4.17 L/100 km, to qualify. A “convert km/L to L/100km” calculation reveals how demanding the thresholds are.
Winter in Hokkaido
In the snow belt, winter tyres, cold engines and heaters cut economy sharply. A car rated 20 km/L, 5 L/100 km, may do 14 to 16 km/L, 6.25 to 7.1 L/100 km, in January. Hybrids lose more in the cold because the engine runs to heat the cabin, so a 28 km/L hybrid, 3.57 L/100 km, may fall to 20 to 22 km/L, 4.5 to 5.0.
Heater and air conditioner
Air conditioning can cost 10 to 20 per cent of fuel economy in town. A car at 15 km/L, 6.67 L/100 km, with the air conditioner on may do 12.5 to 13.5 km/L, 7.4 to 8.0 L/100 km. A “convert km/L to L/100km” calculation on the readings with and without the system shows how much fuel the comfort costs.
Gentle driving
Smooth starts and early lifting off the throttle, taught in Japanese eco-driving courses, improve economy by 10 to 20 per cent. A car that does 15 km/L, 6.67 L/100 km, with a heavy foot may do 17 to 18 km/L, 5.6 to 5.9 L/100 km, when driven gently. The benefit is free and works in any car.
Light vans for small business
Kei vans carry 350 kg of load and do 14 to 17 km/L, 5.9 to 7.1 L/100 km, empty. With a full load they fall to 11 to 13 km/L, 7.7 to 9.1 L/100 km. A florist or a delivery service driving 60 km a day uses 4 to 5 litres, which at 170 yen a litre is under 900 yen a day.
Plug-in hybrids in Japan
A Japanese plug-in hybrid is labelled twice: about 20 km/L on petrol alone, 5 L/100 km, and an electric range of 50 to 60 km. For a commute of 30 km that is fully electric, a day uses no petrol. Drivers who charge rarely get the 20 km/L figure instead, which makes the label a pair of numbers, not a single one.
Heavy trucks in Japan
A 4-tonne truck does 6 to 8 km/L, 12.5 to 16.7 L/100 km, a 10-tonne truck 4 to 5, 20 to 25, and a heavy tractor unit 3 to 3.5, 28.6 to 33.3. Japan's trucking rules set fuel economy standards per weight class, and for the heaviest class the benchmark is in the region of 3 km/L, 33 L/100 km.
Expressways and speed limits
The Japanese expressway limit is 100 km/h, 120 on a few new sections, and consumption at those speeds is higher than the label. A car rated 20 km/L, 5 L/100 km, may return 16 km/L, 6.25 L/100 km, at 100 km/h. In town, with stops and traffic lights, a petrol car can drop to 12 km/L, 8.3 L/100 km.
The dashboard average
A Japanese trip computer shows an average such as "15.2 km/L", which is 6.58 L/100 km. It can be reset at each refuelling. Many drivers keep a log of every tank. The computer reads a little optimistic, usually 2 to 5 per cent, so the figure from a fill-to-fill calculation is the one to trust.
Cost per kilometre in yen
At 170 yen a litre, a car doing 20 km/L costs 8.5 yen a kilometre, one doing 12.5 km/L 13.6 yen, and one doing 25 km/L 6.8 yen. A year of 8,000 km at 20 km/L uses 400 litres and costs 68,000 yen. Japanese drivers cover far fewer kilometres than Europeans, so fuel is a small part of ownership cost.
Taxis and delivery vehicles
Tokyo taxis, traditionally LPG powered, return roughly 8 to 11 km/L, 9.1 to 12.5 L/100 km, though their LPG is cheaper per litre. Small delivery vans run at 10 to 14 km/L, 7.1 to 10 L/100 km. Kei trucks used for farm and market deliveries do 14 to 17 km/L, 5.9 to 7.1 L/100 km.
Motorcycles
Japan's small motorcycles are some of the most efficient vehicles ever made. A 110 cc commuter does 55 to 65 km/L, 1.5 to 1.8 L/100 km, a 250 cc about 30 to 35, 2.9 to 3.3, and a 1,000 cc sports bike 14 to 18, 5.6 to 7.1. At 60 km/L a rider commuting 20 km a day uses a third of a litre.
Used cars exported from Japan
Japanese auction sheets list fuel economy in km/L, together with the cycle. A buyer abroad should convert and then apply the JC08 correction: 22 km/L on JC08, 4.5 L/100 km, may be 18 km/L, 5.6 L/100 km, in a modern test. A “convert km/L to L/100km” calculation on the corrected figure gives a fairer picture.
Electric kei cars
An electric kei car uses about 7 km per kWh, 14.3 kWh per 100 km, and a larger electric car 6 km/kWh, 16.7 kWh. In petrol equivalent that is 1.6 to 1.9 L/100 km, or 53 to 62 km/L of petrol. The comparison is a measure of the energy a car uses, and it ignores the cost of electricity.
More values for convert km/L to L/100km
A longer list of conversions
If the value you need is not in the first list, these further conversions may be close enough to read off directly:
- 3 km/L = 33.3333 L/100km
- 7 km/L = 14.2857 L/100km
- 9 km/L = 11.1111 L/100km
- 12 km/L = 8.33333 L/100km
- 15 km/L = 6.66667 L/100km
- 20 km/L = 5 L/100km
- 35 km/L = 2.85714 L/100km
- 40 km/L = 2.5 L/100km
Common slips with a “convert km/L to L/100km” calculation
Division, not multiplication
The conversion takes 100 and divides it by the figure. Multiplying 25 by 100 gives 2,500, nowhere near a plausible consumption.
The test cycle behind the number
A JC08 figure is 15 to 25 per cent kinder than a WLTC one. After you have converted the units, ask which cycle each number comes from before you rank cars.
The mean of two figures
The average of two km/L figures does not give the average consumption. Average the litres per 100 km and convert that.
Short answers
How do I convert km/L to L/100km?
Take 100 and divide it by the km/L.
What is 20 km/L in L/100 km?
It is 5 L/100 km.
What is 12.5 km/L in L/100 km?
It is 8 L/100 km.
What is 6 L/100 km in km/L?
It is 16.7 km/L.
Is my number sent anywhere?
No, everything is computed in the browser.
More pages and a wrap-up
Other fuel-economy conversions are listed in Convert km/L to MPG (UK), Convert km/L to MPG (US), Convert MPG (US) to L/100km, Convert MPG (UK) to L/100km, Convert L/100km to MPG (UK), Convert km to mi, Convert mi to km, Convert °C to °F, Convert °F to °C. Going the other way is covered by Convert L/100km to km/L.
To sum up, a “convert km/L to L/100km” calculation needs one division of 100 by the km/L and a unit beside the answer. The figure is worked out on your own device, without registration or upload.