Convert km/L to MPG (UK) kilometres per litre ↔ miles per imperial gallon Free Online Secure
Type a value in kilometres per litre and read it in miles per imperial gallon at once. The factor is exact by definition, the arithmetic happens in your browser, and nothing is sent anywhere.
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Convert to miles per imperial gallon
Common values — Convert km/L to MPG (UK) (kilometres per litre ↔ miles per imperial gallon)
| km/L | MPG (UK) |
|---|---|
| 5 | 14.1240468166 |
| 8 | 22.5984749065 |
| 10 | 28.2480936332 |
| 12 | 33.8977123598 |
| 15 | 42.3721404498 |
| 18 | 50.8465685397 |
| 20 | 56.4961872664 |
| 25 | 70.620234083 |
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 MPG (UK): Japanese car culture seen through British eyes
British enthusiasts follow Japanese cars with a passion out of proportion to the distance: tuned coupes, kei cars, drift machines, hybrid taxis, and the little vans that appear on video channels. The specifications they read come in kilometres per litre, while the British language of fuel economy is miles per imperial gallon. A reader who sees a Japanese hybrid at 28 km/L wants to know how that compares with the 65 mpg printed on the British brochure for a car of similar size. To convert km/L to MPG (UK), multiply by 2.8248: 10 km/L is 28.2 mpg, 16 km/L is 45.2 mpg, 20 km/L is 56.5 mpg and 28 km/L is 79.1 mpg. The gallon is the imperial gallon of 4.546 litres. The calculator above multiplies as you type, and the sections below show how Japanese figures read in British units.
The page gives the rule with worked examples, a profile of each unit, a comparison and a long run of cases from the showroom to the car park, followed by the usual slips. The calculation runs in your browser and nothing you type is sent anywhere. Japanese test cycles have been generous, and real consumption is usually higher.
How to convert km/L to MPG (UK): multiply by 2.8248
The rule
The imperial gallon divided by the mile is 4.54609 / 1.609344 = 2.824809, so one kilometre per litre is 2.824809 miles per imperial gallon. To convert km/L to MPG (UK), multiply the km/L by 2.8248: 7 km/L gives 19.8 mpg, 13 gives 36.7 and 24 gives 67.8 mpg. To go back, multiply the mpg by 0.3540.
No curve involved
Both units give distance per quantity of fuel, so one multiplication does it for every value. This differs from converting to litres per 100 km, where the figure is inverted. Double the km/L and you double the mpg, from 8 and 22.6 to 16 and 45.2.
Worked examples
A kei car at 20 km/L makes 56.5 mpg. A drift coupe at 7.5 km/L makes 21.2 mpg. A hybrid at 27 km/L makes 76.3 mpg, and a hybrid minivan at 18 km/L makes 50.8 mpg.
A quick sanity test
The mpg figure should be nearly three times the km/L figure. If a “convert km/L to MPG (UK)” calculation gave a smaller number than you started with, you multiplied by 0.3540 instead of 2.8248.
Kilometres per litre
The measure in Japanese magazines
Distance per litre is how Japanese motoring writers, brochures and trip computers state fuel economy. A larger number is better. Each model usually carries two figures, one from the official cycle and one from the owners' logs.
Where it appears
Japanese magazines, brochures and dashboards.
MPG (UK)
The measure in British magazines
Miles per imperial gallon is what British writers use, with the gallon of 4.546 litres. It is also the unit of British car adverts and of the conversation among enthusiasts. A larger number is better.
Where it appears
British magazines, adverts and car-club newsletters.
km/L set beside UK MPG
One km/L is 2.8248 UK mpg, so the mpg figure is nearly three times larger. 10 km/L is 28.2 mpg, 20 is 56.5 and 30 is 84.7. The car and its fuel use are the same in each.
The conversion is exact. The commonest trap is the US gallon, which would make 20 km/L into 47.0 mpg and the car look worse by 17 per cent.
Where the conversion shows up
Tuned and sports coupes
A turbocharged coupe from the 1990s is credited with 8 to 10 km/L on the old Japanese cycle, 22.6 to 28.2 UK mpg. Enthusiasts' logs show 18 to 24 mpg in normal driving and 12 to 15 on track. A “convert km/L to MPG (UK)” calculation gives the start, and the owners' reports the reality.
Kei cars
Kei cars with 660 cc engines return 17 to 22 km/L on the modern cycle, 48.0 to 62.1 UK mpg, and 13 to 18 in use, 36.7 to 50.8. They are loved by British enthusiasts who import them for small-town use, and they are cheap to run though slow on motorways.
Hybrids
A Japanese hybrid hatchback is rated 25 to 30 km/L under WLTC, 70.6 to 84.7 UK mpg. In British brochures a comparable hybrid carries 60 to 70 mpg. Both claims are laboratory figures, and real use is typically 55 to 62 mpg for these cars.
Drift and track cars
A car used for drifting or on the track may use a litre every 2 to 4 km, 2 to 4 km/L, which is 5.6 to 11.3 UK mpg. A tank of 60 litres lasts only 120 to 240 km. Track-day costs are therefore dominated by fuel, tyres and brakes, not by the price of the car itself.
Fuel quality and octane
Most high-performance Japanese cars are designed for premium petrol. In Britain that is 97 RON super unleaded. A coupe at 9.5 km/L, 26.8 mpg, on ordinary 95 RON may lose power and return 5 per cent less, 9.0 km/L, 25.5 mpg. The manufacturer's figure always assumes the recommended fuel.
A worked example
You compare a Japanese hybrid at 24 km/L with a British brochure figure of 62 mpg for a similar hatchback. The Japanese car is 67.8 mpg, but under a JC08 cycle. After a 20 per cent correction it is 54.2 mpg, so the British car, at 62 mpg on the WLTP cycle, is ahead. A “convert km/L to MPG (UK)” calculation followed by the cycle correction gives the fair comparison.
The mental shortcut
To convert km/L to MPG (UK) in your head, treble the figure and take off 6 per cent. For 15 km/L: 45 less 2.7 is 42.3, against the exact 42.4. For 10: 30 less 1.8 is 28.2, which is exact. The error is below half a per cent.
Spreadsheet formulas
With the km/L in column A, put =A2*2.824809 in column B for UK mpg. The reverse is =B2*0.354006. As cross-checks, =100/A2 gives L/100 km and =A2*2.352146 gives US mpg.
Rounding on magazines
Japanese magazines give km/L to one decimal, British ones whole mpg. 13.2 km/L is 37 mpg, not 37.29. The old cycle is 20 to 35 per cent kinder than the road, so extra decimals tell you nothing.
Landmarks to memorise
5 km/L is 14.1 mpg. 8 is 22.6. 10 is 28.2. 12 is 33.9. 15 is 42.4. 20 is 56.5. 25 is 70.6. 30 is 84.7. With these landmarks nearly every mental convert km/L to MPG (UK) is possible.
Reference ladder
7.5 km/L: 21.2 mpg. 10.5: 29.7. 13: 36.7. 15.5: 43.8. 19: 53.7. 26: 73.4. A table like this lets you test a calculator output at a glance.
Checking by reversing
To check a “convert km/L to MPG (UK)” calculation result, divide the answer by 2.8248. If 43.8 mpg gave 15.5 km/L, then 43.8 / 2.8248 = 15.5. A second test is size: the mpg figure must come out almost three times larger.
Link to L/100 km and US mpg
20 km/L is 5 L/100 km, 56.5 UK mpg and 47.0 US mpg. Multiply km/L by 2.352 for US mpg and 2.825 for UK. These express the same consumption, and a “convert km/L to MPG (UK)” calculation just swaps the label.
Two routes to one answer
You can multiply the km/L by 2.8248 directly, or go through litres per 100 km: 100 divided by the km/L, then 282.481 divided by that. If the routes disagree, a digit was copied wrongly.
Japanese hybrid taxis
Hybrid taxis in Tokyo return 18 to 20 km/L, 50.8 to 56.5 UK mpg, in continuous city use, comparable with a British hybrid in town at 55 to 65 mpg. The comparison suggests the technology is equal, and the differences are in the test cycle and the fuel quality.
Annual mileage and running cost
The average British driver covers about 5,000 miles a year in a second car and 10,000 in a first. A Japanese import at 12 km/L, 33.9 mpg, uses 148 gallons, 671 litres, over 5,000 miles, which at 1.50 pounds a litre is 1,006 pounds. A kei car at 20 km/L, 56.5 mpg, would use 88 gallons, 402 litres, and cost 603 pounds.
Reading owners' logs
Enthusiast forums collect owners' own fuel logs, usually in mpg or km/L depending on the country. A Japanese forum thread with an average of 11.2 km/L equals 31.6 UK mpg. A British thread for the same model at 30 mpg is 10.6 km/L. The two groups of owners agree within 6 per cent, which is as close as one can expect.
Importing for show use
Many imported cars are kept for shows and weekend use, not daily driving. A car at 9 km/L, 25.4 mpg, driven 1,500 miles a year uses 59 gallons, 268 litres, costing 402 pounds. At that mileage the difference between 9 and 12 km/L is only about 100 pounds a year, small beside insurance and storage.
Motorway driving at 70 mph
A Japanese car whose label gives 18 km/L, 50.8 mpg, in the mixed cycle will often return 14 to 15 km/L, 39.5 to 42.4 mpg, at a steady 70 mph, 113 km/h. Small-engined cars and kei cars are slowest to react, since they run at high revs. The conversion tells you the figure, and a motorway test gives the real value.
Weight and aerodynamics
A large Japanese minivan at 10.5 km/L, 29.7 mpg, uses 9.52 L/100 km, while a hatchback at 17 km/L, 48.0 mpg, uses 5.88. The 62 per cent difference comes largely from weight and a boxy shape, not from engine technology. A reader comparing models of different classes should read both figures with that in mind.
Cold starts and short runs
Japanese cars are often used for short trips, and short trips are the enemy of fuel economy. A car that does 15 km/L, 42.4 mpg, on a long run may do 9 km/L, 25.4 mpg, on journeys of 3 km. The difference of 6 km/L equals 4.4 litres per 100 km extra, so ten kilometres of short hops burn 0.44 litres more.
When the numbers mislead
A km/L figure on a Japanese listing, converted to mpg, still carries all its original assumptions: the test cycle, the fuel, the state of the engine and the driver. The conversion is perfect arithmetic, but it cannot make a bad number good. Treat any single figure as a starting point, and trust fill-to-fill logs over brochures.
Kei trucks and vans
Kei vans for deliveries return 14 to 17 km/L, 39.5 to 48.0 UK mpg, empty, and 10 to 13, 28.2 to 36.7, loaded. British importers who use them for small businesses judge them against a panel van at 35 to 40 mpg, which carries much more but costs more to buy.
Japanese motorcycles in Britain
A 125 cc commuter bike returns 45 to 60 km/L, 127 to 170 UK mpg, a 250 cc about 28 to 35, 79 to 99, and a 600 cc 17 to 22, 48 to 62. British riders have bought Japanese bikes for decades, and they quote mpg in magazines. A “convert km/L to MPG (UK)” calculation puts a Japanese figure into that habit.
Taxes and the cost of a trip
British vehicle tax depends on carbon dioxide, so a car at 15 km/L, 42.4 mpg, 6.67 L/100 km, emitting 154 g/km, pays more than one at 20 km/L, 56.5 mpg, 115 g/km. Fuel at 1.50 pounds a litre then costs 10.0 pence per kilometre for the first and 7.5 for the second.
Kilometres versus miles
A Japanese car reports its odometer in kilometres, and a British one in miles. 60,000 km is 37,282 miles, and 100,000 km is 62,137 miles. A buyer comparing wear should convert the distance as well as the fuel economy, so that an imported coupe is judged by miles and not by kilometres.
Gran turismo and big engines
Big-engine Japanese saloons with V8s return 7 to 9 km/L, 19.8 to 25.4 UK mpg, while a small hot hatch returns 12 to 15, 33.9 to 42.4. A V8 at 8 km/L uses 12.5 L/100 km. A British enthusiast who knows his own 4.0 litre car at 22 mpg, 12.8 L/100 km, finds the comparison very close.
Diesel and the Japanese market
Diesel is rare in Japanese passenger cars but exists in four-wheel drives. A diesel SUV at 11 km/L is 31.1 UK mpg, and a petrol SUV at 9 km/L 25.4. A litre of diesel holds 12 per cent more energy, so the diesel's real advantage is about 9 per cent in energy terms, not the 22 per cent suggested by the mpg figures.
Electric cars and the kWh
Japanese electric cars state km per kWh. 7 km/kWh is 14.3 kWh per 100 km, and 9 km/kWh is 11.1. British electric cars are rated in miles per kWh: 4.3 miles per kWh equals 6.9 km/kWh. In petrol-equivalent terms 14.3 kWh per 100 km is about 1.6 L/100 km, 176 UK mpg.
More values for convert km/L to MPG (UK)
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 = 8.47443 MPG (UK)
- 7 km/L = 19.7737 MPG (UK)
- 9 km/L = 25.4233 MPG (UK)
- 12 km/L = 33.8977 MPG (UK)
- 15 km/L = 42.3721 MPG (UK)
- 20 km/L = 56.4962 MPG (UK)
- 35 km/L = 98.8683 MPG (UK)
- 40 km/L = 112.992 MPG (UK)
Common slips with a “convert km/L to MPG (UK)” calculation
Using the wrong direction
From km/L to mpg the number nearly triples. If 20 became 7.1, you used 0.3540, the factor for the opposite direction.
Using the US gallon
With the US gallon, 20 km/L would be 47.0 mpg, not 56.5. British figures use the imperial gallon, so use 2.8248.
Ignoring the test cycle
A figure from the old Japanese cycle is 20 to 35 per cent better than real use. Convert the unit first and then ask which cycle each figure comes from.
Short answers
How do I convert km/L to MPG (UK)?
Multiply the km/L by 2.8248.
How many UK mpg is 10 km/L?
28.2 mpg.
How many UK mpg is 20 km/L?
56.5 mpg.
How many km/L is 40 UK mpg?
14.2 km/L.
Does my number leave my device?
No, the calculation runs in your browser.
More pages and a wrap-up
For other fuel-economy conversions see Convert km/L to MPG (US), Convert km/L to L/100km, Convert MPG (US) to MPG (UK), Convert L/100km to MPG (UK), Convert MPG (UK) to MPG (US), Convert km to mi, Convert mi to km, Convert °C to °F, Convert °F to °C. For the opposite direction see Convert MPG (UK) to km/L.
In short, a “convert km/L to MPG (UK)” calculation means one multiplication by 2.8248 and a unit written next to the result. Your figure is calculated locally, with no account and no upload.