Convert MPG (US) to km/L miles per US gallon ↔ kilometres per litre Free Online Secure
Type a value in miles per US gallon and read it in kilometres per litre 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 kilometres per litre
Common values — Convert MPG (US) to km/L (miles per US gallon ↔ kilometres per litre)
| MPG (US) | km/L |
|---|---|
| 15 | 6.37715561145 |
| 20 | 8.50287414861 |
| 25 | 10.6285926858 |
| 30 | 12.7543112229 |
| 35 | 14.8800297601 |
| 40 | 17.0057482972 |
| 50 | 21.2571853715 |
| 60 | 25.5086224458 |
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.
MPG (US) to km/L: American fuel economy as seen from Seoul, Manila and Mumbai
American brands sell pickups, SUVs and sedans across Asia and Latin America, where fuel economy is counted in kilometres per litre. The brochure may carry the EPA label figure in mpg, a Korean or Philippine dealer may quote km/L, and a buyer comparing the two needs a conversion that bridges miles, gallons and kilometres, litres. To convert MPG (US) to km/L, multiply by 0.4251: 20 mpg is 8.50 km/L, 30 mpg is 12.75 km/L, 40 mpg is 17.0 km/L and 50 mpg is 21.3 km/L. The gallon is the US gallon of 3.785 litres. The calculator above multiplies as you type, and the sections below show how the numbers behave on labels, in trip logs and on the road in the countries that count in km/L.
The page gives the rule with worked examples, a profile of each unit, a comparison and a long run of Asia-focused and ownership cases, followed by the usual slips. The calculation runs in your browser and nothing you type is sent anywhere. Official figures come from test cycles that differ by country, and real driving is usually worse.
How to convert MPG (US) to km/L: multiply by 0.4251
The rule
One mile is 1.609344 km and one US gallon is 3.785412 litres, so one mile per gallon is 1.609344 / 3.785412 = 0.425144 km per litre. To convert MPG (US) to km/L, multiply the mpg by 0.4251: 24 mpg gives 10.2 km/L, 37 gives 15.7 km/L and 58 gives 24.7 km/L. To go back, multiply km/L by 2.352.
A true proportion
Both units measure distance per volume, so the conversion is one multiplication that is the same everywhere on the scale. This is unlike the conversion to litres per 100 km, where the figure is inverted. Doubling the mpg doubles the km/L, and there is no curve to worry about.
Worked examples
A pickup at 19 mpg makes 8.08 km/L. A midsize SUV at 25 mpg makes 10.6 km/L. A sedan at 34 mpg makes 14.5 km/L, and a hybrid at 54 mpg makes 23.0 km/L.
A quick sanity test
The km/L figure should come out at a little under 43 per cent of the mpg figure. If a “convert MPG (US) to km/L” calculation gave a larger number than you started with, you multiplied by 2.352 instead of 0.4251.
MPG (US)
The EPA unit
Miles per US gallon is the unit of the EPA window label, American reviews and federal regulations. A bigger number means a more economical vehicle. The gallon is the US gallon of 3.785 litres.
Where it appears
EPA labels, American brochures and reviews, and export documents for US-built vehicles.
Kilometres per litre
The Asian and Latin American unit
Distance per litre is the label of Japan, Korea, Taiwan, India, Brazil and others. A bigger number means a more economical vehicle. It is also the easiest unit for costing a trip, since price per litre divided by km/L is the price per kilometre.
Where it appears
Labels and brochures in Asia and Latin America, trip computers and fleet reports.
MPG (US) set beside km/L
One mpg is 0.4251 km/L, so the km/L figure is about 57 per cent smaller. 20 mpg is 8.50 km/L, 40 is 17.0 and 60 is 25.5. The vehicle is the same, and only the units of distance and volume have changed.
The conversion is exact. The commonest trap is the imperial gallon, which would make 30 mpg into 10.6 km/L instead of 12.75.
Where the conversion shows up
Importing American vehicles to Asia
A dealer in Seoul, Manila or Bangkok who sells a US-built pickup shows the EPA mpg figure alongside local rivals in km/L. A pickup at 19 mpg, 8.08 km/L, can then be set against a Japanese pickup at 11 km/L. The Asian rival is 36 per cent better on paper, and a “convert MPG (US) to km/L” calculation makes the gap visible at once.
Trip logs and apps
Fuel-tracking apps accept either mpg or km/L. An owner of a US-built SUV who logs 520 km on 61 litres gets 8.52 km/L, which is 20.0 mpg. The app can show either, but the label on the vehicle will be in the other unit, so the conversion links the logbook to the brochure.
Fleet purchases
A company buying ten vehicles compares offers from American and Asian makers. A pickup at 22 mpg, 9.35 km/L, uses 1,070 litres over 10,000 km, while one at 12 km/L uses 833. The saving of 236 litres a vehicle is 2,362 litres for the fleet, which at 1.2 dollars a litre is 2,834 dollars a year.
Cost per kilometre
Price per litre divided by km/L gives the price per kilometre. A pickup at 8.08 km/L with fuel at 1.20 dollars a litre costs 14.9 cents a kilometre, and a sedan at 14.5 km/L costs 8.3 cents. A buyer thinking in mpg has to convert both the volume and the distance, which is why km/L is the easier unit for a budget.
Speed and consumption
The US Department of Energy puts the cost of speed at about 7 per cent for every 5 mph above 50. A car doing 34 mpg, 14.5 km/L, at 55 mph falls to 31.6 mpg, 13.4 km/L, at 60 and 29.4 mpg, 12.5 km/L, at 65. Asian expressways with limits of 100 km/h, 62 mph, sit in that range.
Cold and heat
Cold weather at minus 7 °C can cut fuel economy by 15 per cent on short trips, so 30 mpg, 12.75 km/L, becomes 25.5 mpg, 10.8 km/L. Air conditioning in a hot, humid city can cost another 10 to 25 per cent. In Singapore or Manila the second effect is the more important one, and a “convert MPG (US) to km/L” calculation is only the starting point.
Carbon dioxide per kilometre
A litre of petrol gives 2.31 kg of carbon dioxide. At 12.75 km/L, 30 mpg, a car emits 181 g/km, and at 17.0 km/L, 40 mpg, 136 g/km. Asian regulations often use g/km, so km/L is the natural step between the American label and the local rule. Divide 2,310 by the km/L to find the grams per kilometre.
Diesel against petrol
A litre of diesel holds 12 per cent more energy than a litre of petrol. A pickup at 25 mpg on diesel, 10.6 km/L, therefore uses about the same energy as a petrol pickup at 22.3 mpg, 9.5 km/L. The mpg of the diesel is flattered by the denser fuel, which is why comparisons across fuels should be done in energy per kilometre.
A worked example
You compare an American crossover at 26 mpg with a Japanese one at 12.5 km/L. The first is 11.05 km/L, so the Japanese one is 13 per cent better. At 15,000 km a year the American one uses 1,357 litres and the Japanese 1,200, a difference of 157 litres. Doing a “convert MPG (US) to km/L” calculation on the American figure is all it takes.
The mental shortcut
To convert MPG (US) to km/L in your head, multiply by 17 and divide by 40. For 30 mpg: 30 × 17 = 510, and 510 / 40 = 12.75. The error is below 0.05 per cent. For a rough value, take a little less than half of the mpg figure.
Spreadsheet formulas
With the mpg in column A, put =A2*0.425144 in column B for km/L. The reverse is =B2*2.352146. As a cross-check, =235.215/A2 gives L/100 km, and 100 divided by that value must equal the km/L figure.
Rounding on labels
The EPA prints whole numbers of mpg, so 28 mpg is 11.9 km/L, not 11.904. The test accuracy is 3 to 5 per cent, so two figures are enough. Asian labels print km/L to one decimal, which is a different level of precision from the American one.
Landmarks to memorise
10 mpg is 4.25 km/L. 20 is 8.50. 30 is 12.75. 40 is 17.0. 50 is 21.3. 60 is 25.5. 70 is 29.8. With these landmarks nearly every mental convert MPG (US) to km/L is possible.
Reference ladder
14 mpg: 5.95 km/L. 21: 8.93. 29: 12.3. 36: 15.3. 44: 18.7. 57: 24.2. A table like this lets you test a calculator output at a glance.
Korean labels
Korea grades vehicles by km/L, and the top grades for passenger cars lie in the region of 16 km/L, 6.25 L/100 km, or better in the combined cycle. An American sedan at 36 mpg, 15.3 km/L, would fall just short. Korean buyers of foreign cars often ask for the km/L equivalent of the EPA label to see which grade it would take.
Checking by reversing
To check a “convert MPG (US) to km/L” calculation result, multiply the answer by 2.352. If 36 mpg gave 15.3 km/L, then 15.3 × 2.352 = 36.0. A second test is size: the km/L figure must be a little under 43 per cent of the mpg.
Link to L/100 km and UK mpg
30 US mpg is 12.75 km/L, 7.84 L/100 km and 36.0 UK mpg. The imperial gallon makes the same car look 20 per cent more economical. These express the same consumption, and a “convert MPG (US) to km/L” calculation just swaps the label.
Two routes to one answer
You can multiply the mpg by 0.4251 directly, or go through litres per 100 km: 235.215 divided by the mpg, then 100 divided by the result. If the routes disagree, a digit was copied wrongly.
Mid-size sedans and compact crossovers
The mid-size sedan is America's traditional family car and returns 30 to 34 mpg, 12.8 to 14.5 km/L, 6.9 to 7.8 L/100 km. A compact crossover returns 27 to 31 mpg, 11.5 to 13.2 km/L. These classes compete in Asia with local models at 13 to 17 km/L, so the difference is modest and sometimes in the American car's favour.
Large SUVs and pickups on long trips
On a 1,000 km drive a large SUV at 17 mpg, 7.23 km/L, uses 138 litres, while a mid-size sedan at 32 mpg, 13.6 km/L, uses 73.5. The 65 litres of difference cost 78 dollars at 1.20 dollars a litre. Over a 40,000 km year the gap is 2,590 litres, 3,110 dollars, which is why the choice of vehicle dominates fuel cost.
Car clubs and enthusiast reports
Owners of American cars in Asia often publish fuel logs in car-club forums. A Mustang owner who reports 7.5 km/L in town and 11.5 on a highway is stating 17.6 and 27.0 mpg, 13.3 and 8.7 L/100 km. The two units tell the same story, and enthusiasts convert as a matter of course to compare with US owners.
Philippines and Thailand
In the Philippines and Thailand, the pickup truck is the favourite vehicle and diesel pickups return 10 to 13 km/L, 7.7 to 10.0 L/100 km. An American diesel pickup of 25 mpg is 10.6 km/L. This is well within the local range, which explains why American pickups compete with Japanese ones, but at a higher price.
India's premium imports
Premium imports to India are advertised with the manufacturer's figures, often in mpg or L/100 km. A large SUV at 18 mpg is 7.65 km/L, and a sedan at 30 mpg 12.75 km/L, against local cars at 18 to 24 km/L. Indian buyers are used to the higher figures and can be surprised by the real cost of a big engine.
Brazil and flex-fuel
Brazil has its own label in km/L for petrol and ethanol. An American flex-fuel vehicle at 24 mpg on petrol, 10.2 km/L, will do about 17.5 mpg, 7.44 km/L, on E85. Brazilian drivers use the 70 per cent price rule between ethanol and petrol, and the same conversion applies to US models sold there.
Motorcycles and scooters
A touring motorcycle at 45 mpg is 19.1 km/L, a sport bike at 38 mpg 16.2 km/L and a scooter at 85 mpg 36.1 km/L. Asian small motorcycles reach 50 to 70 km/L, 118 to 165 mpg, so the contrast between the American and Asian markets is striking when expressed in one unit.
Hybrid and electric vehicles
A hybrid at 56 mpg is 23.8 km/L. An electric vehicle rated at 110 MPGe is equivalent to 46.8 km on a litre of petrol, though it uses 30.6 kWh per 100 miles, 19.0 kWh per 100 km. The unit conversions tell you nothing about price, since electricity and petrol are sold in very different ways.
Heavy trucks and buses
A US heavy truck at 6.5 mpg does 2.76 km/L, and a city bus at 3.5 mpg 1.49 km/L. A truck doing 100,000 km a year at 2.76 km/L uses 36,200 litres, and a ten per cent improvement saves 3,600 litres. Fleet owners in Asia compare these figures with local trucks that do 3 to 4 km/L.
Tank range
A pickup with a 26 gallon tank, 98 litres, at 19 mpg, 8.08 km/L, has a range of 792 km. A sedan with a 15 gallon tank, 57 litres, at 34 mpg, 14.5 km/L, has 826 km. The big tank of the pickup merely matches the small tank of the sedan, because its engine is thirstier.
More values for convert MPG (US) to km/L
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 MPG (US) = 1.27543 km/L
- 7 MPG (US) = 2.97601 km/L
- 9 MPG (US) = 3.82629 km/L
- 12 MPG (US) = 5.10172 km/L
- 15 MPG (US) = 6.37716 km/L
- 20 MPG (US) = 8.50287 km/L
- 35 MPG (US) = 14.88 km/L
- 40 MPG (US) = 17.0057 km/L
Common slips with a “convert MPG (US) to km/L” calculation
Using the wrong direction
From mpg to km/L the number falls. If 30 mpg became 70.6, you multiplied by 2.352, the factor for the opposite direction.
The gallon in the source
A British or Canadian figure uses the imperial gallon. 30 imperial mpg is 10.6 km/L, whereas 30 US mpg is 12.75 km/L. Check which one the brochure uses before you convert.
Averaging km/L
The mean of two km/L figures is not the mean consumption. Average the litres per 100 km first and convert that value.
Short answers
How do I convert MPG (US) to km/L?
Multiply the mpg by 0.4251.
How many km/L is 30 mpg?
12.75 km/L.
How many km/L is 50 mpg?
21.3 km/L.
How many mpg is 15 km/L?
35.3 mpg.
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 MPG (US) to L/100km, Convert MPG (US) to MPG (UK), Convert L/100km to km/L, Convert MPG (UK) to km/L, Convert km/L to L/100km, Convert km to mi, Convert mi to km, Convert °C to °F, Convert °F to °C. For the opposite direction see Convert km/L to MPG (US).
In short, a “convert MPG (US) to km/L” calculation means one multiplication by 0.4251 and a unit written next to the result. Your figure is calculated locally, with no account and no upload.