Convert L/100km to MPG (US) litres per 100 kilometres ↔ miles per US gallon Free Online Secure
Type a figure in litres per 100 kilometres and read it in miles per US gallon 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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Common values — Convert L/100km to MPG (US) (litres per 100 kilometres ↔ miles per US gallon)
| L/100km | MPG (US) |
|---|---|
| 3 | 78.4048611111 |
| 4 | 58.8036458333 |
| 5 | 47.0429166667 |
| 6 | 39.2024305556 |
| 7 | 33.6020833333 |
| 8 | 29.4018229167 |
| 10 | 23.5214583333 |
| 12 | 19.6012152778 |
| 15 | 15.6809722222 |
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.
L/100 km to MPG (US): explaining a European car to an American road
A European compact that uses 5.5 litres per 100 km sounds frugal at home, yet the same car on an American forum is described as "about 43 mpg". The two units look unrelated because one measures fuel per distance and the other distance per fuel, so they are reciprocals and a single multiplier cannot link them. To convert L/100km to MPG (US), divide 235.2 by the figure in litres: 4 L/100 km is 58.8 mpg, 6 L/100 km is 39.2 mpg, 8 L/100 km is 29.4 mpg and 12 L/100 km is 19.6 mpg. The gallon is the US gallon of 3.785 litres. The calculator above does the division as you type, and the sections below show what the numbers mean for rental cars, road trips, test cycles and fuel bills on the other side of the Atlantic.
The page gives the rule with worked examples, a profile of each unit, a comparison and a long run of travel and ownership cases, followed by the usual slips. The calculation runs in your browser and nothing you type is sent anywhere. Official fuel-economy figures are laboratory results and real driving is usually somewhat worse.
How to convert L/100km to MPG (US): divide 235.2 by the consumption
The rule
One US gallon is 3.785412 litres and one mile is 1.609344 km. Miles per gallon is distance over fuel, and L/100 km is fuel over distance, so they are reciprocals. To convert L/100km to MPG (US), divide 235.215 by the L/100 km: 235.215 / 5 = 47.0 mpg, 235.215 / 7 = 33.6 mpg and 235.215 / 10 = 23.5 mpg. Divide the same constant by mpg to go the other way.
Why a single multiplier fails
Halve the consumption and mpg doubles: 8 L/100 km is 29.4 mpg, 4 L/100 km is 58.8 mpg. A multiplier would turn 4 into twice the value of 2, but the true value at 2 L/100 km is 117.6 mpg, four times larger than at 8. So each value has to be calculated, and a table of rounded pairs misleads.
Worked examples
A diesel hatchback at 4.2 L/100 km makes 56.0 mpg. A family estate at 6.8 L/100 km makes 34.6 mpg. A large SUV at 11 L/100 km makes 21.4 mpg, and a pickup at 14 L/100 km makes 16.8 mpg.
A quick sanity test
Multiply the two numbers together and you should get about 235. A car at 8 L/100 km and 29.4 mpg gives 235.2. If a “convert L/100km to MPG (US)” calculation gave a product far from that, an error crept in.
Litres per 100 kilometres
How Europe, Canada and much of the world express it
Fuel per distance is the natural unit for cost: multiply by the price per litre and the length of the trip. A smaller number is better. Labels in Europe, Canada, Australia and most other countries use it.
Where it appears
Type-approval documents, European labels and metric car reviews.
Miles per US gallon
How the United States expresses it
Distance per fuel is the American habit and the unit of the EPA window label. A larger number is better. The US gallon of 3.785 litres is smaller than the imperial gallon of 4.546 litres used in Britain.
Where it appears
EPA labels, American car reviews, rental-car brochures and regulations.
L/100 km set beside MPG
The two scales run opposite ways: 4 L/100 km is 58.8 mpg, 8 is 29.4 and 16 is 14.7. Multiply the pair and the answer stays at 235.2. A small L/100 km is a high mpg.
The conversion is exact. The commonest trap is the US versus the imperial gallon, which shifts the result by 20 per cent.
Where the conversion shows up
Test cycles compared
European labels use the WLTP cycle and American ones the EPA cycles, which usually give somewhat higher consumption for the same car. A European model rated 5.5 L/100 km, 42.8 mpg, may carry an EPA combined figure near 38 mpg, 6.2 L/100 km. When you convert L/100km to MPG (US), remember that the difference is partly the test, not only the car.
Road trips
An American road trip of 3,000 miles, 4,828 km, in a car using 7 L/100 km, 33.6 mpg, burns 338 litres, 89 gallons. At 3.50 dollars a gallon, 0.92 dollars a litre, that is 312 dollars. The same trip in a pickup at 14 L/100 km costs 624 dollars. Fuel is often the largest cost of a long journey.
Speed limits
American interstate limits of 65 to 80 mph, 105 to 129 km/h, are higher than most European limits, and consumption rises quickly with speed. A car using 6 L/100 km at 100 km/h may use 7.2 at 120 km/h and 8.5 at 130, which is 39.2, 32.7 and 27.7 mpg.
Rental cars
An economy rental sold with "up to 40 mpg highway" uses 5.9 L/100 km on the open road. A full-size sedan at 28 mpg combined uses 8.4 L/100 km, and a standard SUV at 25 mpg 9.4. Rental firms charge the fuel per gallon at refill, so the mpg figure is a good guide to the cost of returning a tank unfilled.
Carbon dioxide
Petrol gives 2.31 kg of carbon dioxide per litre and diesel 2.68 kg. A car at 7 L/100 km on petrol, 33.6 mpg, emits 162 g/km. A diesel at 5 L/100 km, 47 mpg, emits 134 g/km. Emissions per kilometre are the unit of European regulation, while mpg is the unit of American fuel-economy standards.
Tanks and range
A tank of 14 gallons, 53 litres, in a car using 6.5 L/100 km, 36.2 mpg, gives a range of 815 km, 507 miles. A pickup tank of 26 gallons, 98 litres, at 13 L/100 km, 18.1 mpg, gives 757 km. Range is tank size divided by consumption, and a bigger tank can hide a thirstier engine.
A worked example
You are comparing a European hatchback at 5.2 L/100 km with an American sedan at 36 mpg. The hatchback is 45.2 mpg and the sedan 6.5 L/100 km. At 15,000 km a year the hatchback burns 780 litres and the sedan 980, 200 litres more, about 52 gallons. A “convert L/100km to MPG (US)” calculation on whichever figure you have gives the same comparison.
The mental shortcut
To convert L/100km to MPG (US) in your head, divide 240 by the consumption and remove 2 per cent. For 8 L/100 km: 240 / 8 = 30, less 2 per cent is 29.4, the exact answer. A rougher approach is 250 divided by the consumption, which overstates the result by 6 per cent.
Spreadsheet formulas
With the L/100 km in column A, put =235.215/A2 in column B for mpg (US). The reverse is the same formula, =235.215/B2. For km/L use =100/A2, and for imperial mpg use =282.481/A2, as a cross-check for any figure from Britain.
Rounding on labels
American labels print mpg as whole numbers, so 7.4 L/100 km is 32 mpg and not 31.79. European labels give litres to one decimal place. Do not attach more precision to a conversion than the source had. The accuracy of the test itself is about 3 to 5 per cent.
Landmarks to memorise
4 L/100 km is 59 mpg. 5 is 47 mpg. 6 is 39 mpg. 8 is 29 mpg. 10 is 24 mpg. 12 is 20 mpg. 15 is 16 mpg. With these landmarks nearly every mental convert L/100km to MPG (US) is possible, and the product of each pair stays near 235.
Reference ladder
3.5 L/100 km: 67.2 mpg. 4.8: 49.0 mpg. 6.2: 37.9 mpg. 7.2: 32.7 mpg. 9.5: 24.8 mpg. 13: 18.1 mpg. 18: 13.1 mpg. A table like this lets you test a calculator output at a glance.
Checking by reversing
To check a “convert L/100km to MPG (US)” calculation result, divide 235.2 by the answer. If 7.2 L/100 km gave 32.7 mpg, then 235.2 / 32.7 = 7.19. A second test is the product: litres per 100 km times mpg should be near 235.
Link to km/L and imperial MPG
A consumption of 8 L/100 km is 12.5 km/L, 29.4 US mpg and 35.3 imperial mpg. The imperial gallon of 4.546 litres makes the same car look 20 per cent more efficient. These express the same consumption, and a “convert L/100km to MPG (US)” calculation just swaps the label.
Gallons and litres at the pump
American pumps sell by the gallon, 3.785 litres, and prices per gallon look large to a European. A price of 3.50 dollars a gallon is 0.925 dollars a litre. For comparing a trip, convert the price to litres and multiply by the consumption in L/100 km, or convert consumption to mpg and use the price per gallon directly.
Two routes to one answer
You can divide 235.215 by the L/100 km directly, or go through km/L: 100 divided by the consumption, multiplied by 2.352. A third route works in miles per litre. If the routes disagree, a digit was copied wrongly.
Motorcycles and scooters
A touring motorcycle at 50 mpg uses 4.7 L/100 km, a scooter at 80 mpg 2.9 L/100 km and a sport bike at 35 mpg 6.7 L/100 km. American reviewers quote these figures in mpg, so a “convert L/100km to MPG (US)” calculation gives European riders the litres they are used to. Two-wheelers have no official EPA label, which makes their numbers less certain.
Idling and short trips
A warm engine idling burns roughly 0.2 to 0.5 gallons an hour, 0.8 to 1.9 litres. Ten minutes of idling at 0.3 gallons an hour uses 0.05 gallons, 0.19 litres, which is the fuel for about 3 km at 6 L/100 km. Cold starts and short trips raise consumption sharply, and the label does not capture that.
Tyres and roof boxes
Under-inflated tyres cost about 0.2 per cent in fuel economy for each psi lost, so 10 psi under means 2 per cent, which takes a car from 30 to 29.4 mpg, 7.84 to 8.0 L/100 km. A roof box can add 5 to 15 per cent at highway speed, so 7 L/100 km becomes 7.4 to 8.0, or 33.6 mpg falls to 29 to 31.
Hybrids and plug-in hybrids
A conventional hybrid rated at 50 mpg combined uses 4.7 L/100 km, and the most frugal models reach 56 mpg, 4.2 L/100 km. A plug-in hybrid is rated twice: on petrol alone, perhaps 40 mpg, 5.9 L/100 km, and with a charged battery in MPGe. The average depends on how often the battery is charged, so no single figure applies.
Cost per distance
At 30 mpg and 3.50 dollars a gallon a car costs 11.7 cents a mile, which is 7.25 cents per kilometre. In metric terms 7.84 L/100 km at 0.925 dollars a litre gives the same 7.25 cents per kilometre. A “convert L/100km to MPG (US)” calculation followed by a division by the price gives the same answer in the other system.
Towing
Towing a heavy trailer can cut a pickup's economy from 20 mpg to 12 mpg. In metric terms consumption rises from 11.8 to 19.6 L/100 km, an increase of two thirds. For a trip of 1,000 km that is 196 litres rather than 118, 78 litres more, or about 20 gallons.
Electric cars and MPGe
The EPA states electric consumption in kWh per 100 miles and in miles per gallon equivalent, using 33.7 kWh for a gallon. A European figure of 17 kWh per 100 km is 27.4 kWh per 100 miles, which is 123 MPGe. The equivalent petrol consumption is 1.9 L/100 km, though the cost and the emissions depend on how the power is made.
Averaging consumption
Average litres, not miles per gallon. Two cars at 20 and 40 mpg, 11.8 and 5.9 L/100 km, travelling 100 km each use 17.6 litres together, which is 8.8 L/100 km or 26.7 mpg. The arithmetic mean of the mpg, 30, would suggest 7.8 L/100 km, which is too good.
The MPG illusion
Because mpg is a reciprocal, equal gains in mpg do not give equal savings. Going from 10 to 20 mpg saves 11.8 L per 100 km, while going from 30 to 50 saves only 3.1 L. Researchers have shown that people misjudge this, which is one reason several countries label in litres per distance.
Fleet averages
The average new vehicle in the United States is rated around 26 mpg, which is 9.0 L/100 km. The European new-car fleet is closer to 5.5 to 6 L/100 km, 39 to 43 mpg, as measured in laboratory cycles. The figures are not directly comparable because vehicle mix, fuel and test cycle differ, but the gap is clear.
Diesel and petrol
A litre of diesel contains about 12 per cent more energy than a litre of petrol, so a diesel using 5 L/100 km is comparable to a petrol using 5.6. In mpg terms 47.0 for the diesel against 42.0 for the petrol. Comparing the two on mpg alone therefore flatters the diesel: for the same energy use it shows a figure 12 per cent better.
More values for convert L/100km 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 L/100km = 78.4049 MPG (US)
- 7 L/100km = 33.6021 MPG (US)
- 9 L/100km = 26.135 MPG (US)
- 12 L/100km = 19.6012 MPG (US)
- 15 L/100km = 15.681 MPG (US)
- 20 L/100km = 11.7607 MPG (US)
- 35 L/100km = 6.72042 MPG (US)
- 40 L/100km = 5.88036 MPG (US)
Common slips with a “convert L/100km to MPG (US)” calculation
Multiplying instead of dividing
The relation is a reciprocal. Multiplying 8 by 235 gives 1,882, which is not a consumption of any car. Divide the constant by the figure instead.
US and imperial gallons
An imperial mpg is 20 per cent larger than a US mpg for the same car. Use 235.2 for American figures and 282.5 for British ones.
Averaging mpg
The mean of two mpg figures is not the mean consumption. Average the litres per 100 km and convert the result.
Short answers
How do I convert L/100km to MPG (US)?
Divide 235.2 by the figure in L/100 km.
How many mpg is 8 L/100 km?
29.4 mpg.
How many mpg is 5 L/100 km?
47.0 mpg.
How many L/100 km is 30 mpg?
7.84 L/100 km.
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 L/100km to km/L, Convert L/100km to MPG (UK), Convert MPG (UK) to MPG (US), Convert km/L to MPG (US), Convert MPG (US) to km/L, Convert km to mi, Convert mi to km, Convert °C to °F, Convert °F to °C. For the opposite direction see Convert MPG (US) to L/100km.
In short, a “convert L/100km to MPG (US)” calculation means one division of 235.2 by the consumption and a unit written next to the result. Your figure is calculated locally, with no account and no upload.