Convert km/L to MPG (US) kilometres per litre ↔ miles per US gallon Free Online Secure
Type a value in kilometres per litre and read it in miles per US gallon at once. The factor is exact by definition, the arithmetic happens in your browser, and nothing is sent anywhere.
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Common values — Convert km/L to MPG (US) (kilometres per litre ↔ miles per US gallon)
| km/L | MPG (US) |
|---|---|
| 5 | 11.7607291667 |
| 8 | 18.8171666667 |
| 10 | 23.5214583333 |
| 12 | 28.22575 |
| 15 | 35.2821875 |
| 18 | 42.338625 |
| 20 | 47.0429166667 |
| 25 | 58.8036458333 |
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 (US): what a Japanese auction sheet means for an American import
Each year thousands of Japanese-market vehicles that have reached 25 years of age are brought into the United States, where they become legal without the usual safety and emissions certification. Sports coupes, kei trucks and minivans arrive with Japanese paperwork, auction sheets and brochures that quote fuel economy in kilometres per litre. The buyer thinks in miles per US gallon, so the first thing to do is convert. To convert km/L to MPG (US), multiply by 2.352: 8 km/L is 18.8 mpg, 12 km/L is 28.2 mpg, 15 km/L is 35.3 mpg and 20 km/L is 47.0 mpg. The gallon is the US gallon of 3.785 litres, and the mile is 1.609 km. The calculator above multiplies as you type, and the sections that follow show what the numbers mean for imported cars, trucks and motorbikes.
Below come the rule with examples, short notes on each unit, a side-by-side look and a long series of import and ownership cases, ending with the slips people make most. Everything is computed locally in the page. Old Japanese figures came from the gentle 10-15 mode cycle, so real consumption is considerably higher.
How to convert km/L to MPG (US): multiply by 2.352
The rule
A US gallon holds 3.785412 litres and a mile is 1.609344 km, which makes one kilometre per litre 3.785412 / 1.609344 = 2.352146 miles per gallon. For a “convert km/L to MPG (US)” calculation, take the km/L times 2.352: 7 km/L gives 16.5 mpg, 13 gives 30.6 and 22 gives 51.7 mpg. To go back, multiply the mpg by 0.4251.
A constant ratio
Both units measure distance per volume, so the factor is the same all the way along the scale. This is unlike the conversion between mpg and litres per 100 km, which is an inversion. Here nothing bends: doubling the km/L doubles the mpg, from 10 and 23.5 to 20 and 47.0.
Worked examples
A kei truck at 14 km/L is 32.9 mpg. A 1990s sports coupe at 9 km/L is 21.2 mpg. A minivan at 10.5 km/L is 24.7 mpg, and a rotary-engined sports car at 6.5 km/L is 15.3 mpg.
A quick sanity test
Expect the mpg result to be a bit over two and a third times the km/L figure. A smaller number than you began with means 0.4251 was used where 2.352 belonged.
Kilometres per litre
The Japanese figure
Distance per litre is the unit of every Japanese brochure and auction sheet. A higher number is better. Old vehicles are measured on the 10-15 mode cycle, newer ones on JC08 and the most recent on WLTC.
Where it appears
Japanese auction sheets, brochures, import listings and dashboards.
MPG (US)
The American figure
Miles per US gallon is the unit American buyers use. The EPA label shows it, and so do classified ads and enthusiast sites. A higher number is better, and the gallon is 3.785 litres.
Where it appears
EPA labels, American ads and enthusiast forums.
km/L set beside MPG (US)
Expressed in miles per US gallon, a Japanese figure grows to more than twice its size: 10 km/L becomes 23.5 mpg, 20 becomes 47.0 and 30 becomes 70.6. The vehicle and the fuel it burns stay exactly as they were.
Nothing is lost on the way. The mistake that shows up most is using the imperial gallon, which would turn 20 km/L into 56.5 mpg in place of 47.0.
Where the conversion shows up
Sports cars of the 1990s
Japanese sports coupes of the early 1990s were rated 8 to 12 km/L on the old cycle, 18.8 to 28.2 mpg, and real-world use was typically 20 to 30 per cent worse: 15 to 22 mpg. A rotary sports car was rated 6 to 8 km/L, 14.1 to 18.8 mpg, and in hard use drops to 12 to 15. A “convert km/L to MPG (US)” calculation gives the starting point, and the cycle correction the realistic figure.
Kei trucks and vans
The small trucks and vans with 660 cc engines rate 12 to 17 km/L on the old cycle, 28.2 to 40.0 mpg. On American highways at 65 mph with a four-speed gearbox the engine works hard and real use is nearer 25 to 32 mpg. They are economical in town and slow on a freeway.
Minivans and station wagons
Japanese minivans of the 1990s are rated 9 to 12 km/L, 21.2 to 28.2 mpg, and the real figure with a full load of people is 17 to 22 mpg. The conversion shows they use a little less fuel than an equivalent American minivan, but the difference is small.
The 10-15 mode cycle
Before 2008, Japanese cars were tested on the 10-15 mode cycle, which is slow and flat and gives high km/L figures. A car rated 14 km/L under that cycle, 32.9 mpg, will often return 9 to 11 km/L, 21.2 to 25.9 mpg, in mixed American driving. Buyers of 25-year-old cars should apply a correction of 25 to 35 per cent.
Fuel in tanks
A Japanese tank of 50 litres is 13.2 US gallons. At 10 km/L, 23.5 mpg, it gives 500 km, 311 miles. A kei truck's 30 litre tank, 7.9 gallons, at 14 km/L gives 420 km, 261 miles. In Japan nobody worries about range, but across American deserts it matters.
The price of imported fuel
The owner of an imported coupe who fills with 91 octane at 4.00 dollars a gallon pays 1.06 dollars a litre. At 9 km/L, 21.2 mpg, a kilometre costs 11.8 cents and a mile 19.0 cents. At 14 km/L, 32.9 mpg, the mile costs 12.2 cents. A “convert km/L to MPG (US)” calculation followed by the price per gallon gives the cost per mile directly.
Registration and emissions
Once a car is eligible, state rules decide registration and emissions testing. Some states exempt cars over 25 years old from tests, others apply them. The fuel economy figure is irrelevant for registration, but a buyer will want it for budgeting. It is best to know the real consumption before you buy.
A worked example
You are comparing an imported Japanese wagon rated 11 km/L with an American wagon rated 24 mpg. The Japanese one is 25.9 mpg on the old cycle, and about 20 mpg in use after a 25 per cent correction. The American one is 10.2 km/L at 24 mpg. At 12,000 miles a year the Japanese car burns 600 gallons, the American one 500.
The mental shortcut
To convert km/L to MPG (US) without a calculator, double the figure, add a third of it, and a little more. For 15 km/L that gives 30 plus 5, or 35, close to the exact 35.3, and for 12 it gives 24 plus 4, or 28 against 28.2. The error stays under 1 per cent.
Spreadsheet formulas
Put the km/L in column A, then =A2*2.352146 in column B returns mpg, and =B2*0.425144 reverses it. A helper column of =100/A2 returns L/100 km, and =235.215/(100/A2) must bring you back to the same mpg.
Rounding on auction sheets
Sheets print km/L to one decimal, which turns into a whole number of mpg: 13.2 km/L is 31 mpg. The old test cycle was far from the road, so a decimal beyond the first adds nothing.
Landmarks to memorise
Remember that 5 km/L = 11.8 mpg, 8 = 18.8, 10 = 23.5, 12 = 28.2, 15 = 35.3, 20 = 47.0, 25 = 58.8 and 30 = 70.6. With them a mental convert km/L to MPG (US) takes a moment.
Reference ladder
7.5 km/L: 17.6 mpg. 11.5: 27.0. 14.5: 34.1. 18: 42.3. 23: 54.1. 28: 65.9. With a list of this kind any result can be checked quickly.
Checking by reversing
Test a “convert km/L to MPG (US)” calculation answer by multiplying it by 0.4251: 42.3 mpg gives 18.0 km/L, so the 18 you started from came through intact. A second sign of a good result is that mpg sits a bit over two and a third times above km/L.
The 25-year rule
US law lets a vehicle be imported without the usual certification once it is 25 years old. A car built in 2000 becomes eligible in 2025. Because each year adds a new batch, the figures on the auction sheets change: cars from the late 1990s have km/L figures from the 10-15 mode, while those from after 2008 will use JC08.
Link to L/100 km and UK mpg
In 20 km/L there are 5 L/100 km, 47.0 US mpg and 56.5 UK mpg. Multiply km/L by 2.352 for US mpg and 2.825 for UK. The units differ and the consumption does not, so a “convert km/L to MPG (US)” calculation only relabels it.
Two routes to one answer
Go straight with 2.352 times the km/L, or travel via litres per 100 km: 100 ÷ km/L, then 235.215 ÷ that. If the answers drift apart, a digit slipped somewhere.
Reading the equipment and notes
Auction sheets also record accident history, repairs, interior grade and fuel type in Japanese shorthand. A sheet noting a modified engine or an exhaust makes the km/L figure unreliable, because tuned cars burn more than stock ones. A car marked "haioku", the Japanese word for high-octane, needs premium fuel, 91 octane or better in the American system.
Left-hand and right-hand drive
Imported Japanese cars are right-hand drive, which makes tolls, drive-throughs and passing harder, but has no effect on consumption. A car of 12 km/L, 28.2 mpg, burns the same fuel in either configuration. The real costs of an import are shipping, duties, the recommended modifications and the premium fuel.
Shipping and storage
Cars come by ship with a few litres of fuel in the tank, so the first fill-up after delivery is also the first measurement of real consumption. Fill the tank, note the odometer in miles after conversion, and fill again after a 200 mile, 322 km, trip. If it takes 8 gallons, the car makes 25 mpg, 10.6 km/L.
Modifications and economy
Owners often change tyres, fit larger wheels or raise engine output. A change from 15 to 18 inch wheels can reduce economy by 3 to 5 per cent, so 10 km/L, 23.5 mpg, becomes 9.6 km/L, 22.6 mpg. A modification that gains power usually costs mpg, and a tuned engine may need premium fuel.
Choosing between two listings
When two listings show 13 km/L and 11 km/L for similar cars, a quick convert km/L to MPG (US) gives 30.6 and 25.9 mpg. The first car uses 15 per cent less fuel, which at 10,000 miles a year and 4 dollars a gallon saves about 240 dollars. That is worth weighing against condition, mileage and price, but it can decide a close choice.
Auction sheet grades and fuel
An auction sheet lists the grade, mileage in kilometres, equipment and sometimes the fuel economy in km/L. A sheet that says "13.2 km/L" is giving 31.0 mpg. Mileage is in kilometres: 80,000 km is 49,700 miles, which an American title will show once the odometer is converted.
Turbocharged sports coupes
A turbocharged 2.6 litre coupe is rated 8 to 9 km/L, 18.8 to 21.2 mpg, and a 3.0 litre turbo coupe 8 to 10, 18.8 to 23.5. With the boost used, mpg drops to 12 to 16. Owners also run premium fuel, 91 or 93 octane in the American system, which is consistent with the Japanese high-octane fuel for which the engines were designed.
Rotary engines
A 1.3 litre twin-turbo rotary engine returns 6 to 8 km/L on paper, 14.1 to 18.8 mpg, and in driving 11 to 14 mpg, 4.7 to 6.0 km/L. A rotary uses more fuel per power than a piston engine because of its shape and its sealing. Owners accept that cost along with oil consumption.
Hybrids from the late 1990s
The first Japanese hybrids from 1997 to 2000 are reaching eligibility. A hybrid saloon rated 28 km/L on the 10-15 mode, 65.9 mpg, returned about 45 to 50 mpg, 19.1 to 21.3 km/L, in use. Their appeal is as early examples of a technology, not as economical cars today.
Motorcycles and scooters
A 250 cc Japanese motorcycle rated 30 km/L is 70.6 mpg, a 400 cc sports bike at 20 km/L is 47.0 mpg and a 50 cc scooter at 60 km/L is 141 mpg. American riders see these figures in three digits only for small scooters, which is why they attract attention as commuters.
Diesel trucks and SUVs
A Japanese diesel SUV of the 1990s is rated 9 to 11 km/L, 21.2 to 25.9 mpg, and a diesel pickup 10 to 12, 23.5 to 28.2. Diesel contains about 12 per cent more energy per litre than petrol, so the diesel figures are flattering. In energy terms they are 19 to 23 mpg of petrol equivalent.
Commercial vehicles
A one-tonne Japanese delivery van is rated 8 to 10 km/L, 18.8 to 23.5 mpg, and a two-tonne truck 6 to 8, 14.1 to 18.8. A US half-ton pickup does 17 to 22 mpg. The Japanese vehicles carry less, so their consumption per tonne is similar, and the main advantage is lower purchase cost.
More values for convert km/L to MPG (US)
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 = 7.0564375 MPG (US)
- 7 km/L = 16.465 MPG (US)
- 9 km/L = 21.1693125 MPG (US)
- 12 km/L = 28.22575 MPG (US)
- 15 km/L = 35.2821875 MPG (US)
- 20 km/L = 47.0429 MPG (US)
- 35 km/L = 82.3251 MPG (US)
- 40 km/L = 94.0858 MPG (US)
Common slips with a “convert km/L to MPG (US)” calculation
The factor the wrong way round
Going from km/L to mpg raises the number. If 20 km/L turned into 8.5, the factor for the opposite direction, 0.4251, was used.
The test cycle behind an old figure
A figure from the old Japanese cycle is mild. After converting units, take 20 to 35 per cent off before you compare it with a modern EPA label.
Kilometres of mileage
The mileage on an auction sheet is in kilometres. 100,000 km is 62,137 miles, and mixing the two when judging wear is a common error.
Short answers
How do I convert km/L to MPG (US)?
Take the km/L times 2.352.
What is 20 km/L in mpg?
It is 47.0 mpg.
What is 10 km/L in mpg?
It is 23.5 mpg.
What is 40 mpg in km/L?
It is 17.0 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 L/100km, Convert km/L to MPG (UK), Convert MPG (UK) to MPG (US), Convert L/100km to MPG (US), Convert MPG (US) to L/100km, Convert km to mi, Convert mi to km, Convert °C to °F, Convert °F to °C. Going the other way is covered by Convert MPG (US) to km/L.
To sum up, a “convert km/L to MPG (US)” calculation needs one multiplication by 2.352 and a unit beside the answer. The figure is worked out on your own device, without registration or upload.