US MPG
31.36
Fuel Economy Converter: MPG to L/100km Calculator
Convert fuel economy between MPG (US and UK gallons), litres per 100 km, and km per litre. Compare two cars, estimate trip fuel cost, and understand what the numbers mean when you buy a car in the US, UK, or Europe.
MPG to L/100km Converter
Enter a value in any unit. All four common fuel economy units update instantly: US MPG, UK (imperial) MPG, L/100km, and km/L.
UK MPG
37.66
L/100km
7.5000
km/L
13.33
Formulas: L/100km = 235.2146 ÷ US MPG = 282.4809 ÷ UK MPG = 100 ÷ km/L. US gallon = 3.785411784 L, imperial gallon = 4.54609 L, mile = 1.609344 km (all exact by definition).
Trip Fuel Cost Calculator
Plan fuel cost per trip: enter distance, your car's consumption, and the fuel price per litre.
Fuel needed: 39.20 litres
Estimated trip cost: 58.80
Car Fuel Efficiency Comparison
Compare two cars over a year of driving to see the real litre and money difference.
| Car A | Car B | Difference | |
|---|---|---|---|
| Consumption (L/100km) | 7.50 | 10.50 | 3.00 |
| US MPG | 31.36 | 22.40 | 8.96 |
| Litres per year | 1125.0 | 1575.0 | 450.0 |
| Fuel cost per year | 1687.50 | 2362.50 | 675.00 |
Understanding Fuel Economy Numbers
This fuel economy calculator handles the two unit families used around the world. To convert MPG to litres per 100km, divide 235.2146 by the US MPG figure; an L/100km to MPG calculator simply runs the same constant in reverse. The tricky part is US MPG vs UK MPG: the imperial gallon is about 20 percent larger, so an imperial MPG to L/100km conversion uses 282.4809 instead of 235.2146. Always confirm which gallon a quoted figure uses before you compare.
Metric drivers face a similar choice. To turn km per litre into MPG, multiply US MPG by 0.4251, or work in litres per 100 km, the standard across Europe, Australia, and Canada. When you buy a car advertised abroad, convert everything to one unit first: a car fuel efficiency comparison is only fair when both numbers share the same gallon or the same metric base.
Drivers in Japan, India, and Brazil usually think in km/L. Going from km per litre to MPG means dividing by 0.4251, while MPG to km/L multiplies by it; a km/L to L/100km switch is even simpler at 100 divided by the value. As a fuel consumption converter, this tool keeps all four units in sync so you never mix them up.
So what is good fuel economy in practice? The average fuel consumption of a modern petrol compact sits near 6 to 7 L/100km, hybrids dip under 5, and anything above 12 marks a heavy SUV or pickup. Use the reference table below to judge any quoted figure before you sign.
Beyond conversion, this page works as a gas mileage converter with practical extras. Wondering how to calculate fuel consumption for a journey? Enter distance and consumption to get fuel cost per trip from your local fuel price per litre. Real-world fuel economy usually runs 10 to 20 percent worse than lab figures, so add a margin when budgeting, especially for hybrids whose advantage shrinks on highways.
Typical Fuel Consumption by Car Type
Approximate combined real-world figures for petrol cars. Use them as a sanity check when a seller quotes a number.
| Car type | L/100km | US MPG | km/L |
|---|---|---|---|
| Hybrid compact | 4.0 - 5.0 | 47.0 - 58.8 | 20.0 - 25.0 |
| Small hatchback | 5.5 - 7.0 | 33.6 - 42.8 | 14.3 - 18.2 |
| Family sedan | 7.0 - 9.0 | 26.1 - 33.6 | 11.1 - 14.3 |
| Midsize SUV | 9.0 - 12.0 | 19.6 - 26.1 | 8.3 - 11.1 |
| Large pickup | 12.0 - 15.0 | 15.7 - 19.6 | 6.7 - 8.3 |
Table values are rounded guides, not oracle outputs. Exact conversions: 5 L/100km = 47.0429 US MPG; 20 km/L = 5.0 L/100km.
Fuel Economy Conversion FAQs
How do I convert 30 MPG to L/100km?
Divide 235.2146 by the MPG value. For 30 US MPG: 235.2146 ÷ 30 = 7.8405 L/100km. The number 235.2146 is exact by definition: 100 × 3.785411784 litres per US gallon ÷ 1.609344 km per mile.
What is 5 L/100km in MPG?
Use the same constant in reverse: 235.2146 ÷ 5 = 47.0429 US MPG. So a car rated at 5 L/100km achieves about 47.04 miles per US gallon.
How many km/L is 1 MPG?
1 US MPG equals 0.4251 km/L. For example, 25 US MPG equals 10.6286 km/L. To go the other way, 15 km/L equals 35.2822 US MPG.
What is the difference between US MPG and UK MPG?
The US gallon (3.7854 litres) is smaller than the imperial gallon (4.5461 litres), so the same car scores higher in UK MPG: 1 US MPG = 1.2009 UK MPG. For example, 30 US MPG = 36.0285 UK MPG. Always check which gallon a figure uses before comparing cars from the US and the UK.
What is the formula to convert MPG to L/100km?
L/100km = 235.2146 ÷ MPG (US). For imperial MPG, use 282.4809 ÷ MPG (UK). Example: 40 UK MPG = 282.4809 ÷ 40 = 7.0620 L/100km.
How do I convert L/100km to MPG?
MPG (US) = 235.2146 ÷ L/100km. So 6 L/100km = 235.2146 ÷ 6 = 39.2024 US MPG, or 282.4809 ÷ 6 = 47.0802 UK MPG.
How do I convert between km/L and L/100km?
They are reciprocals: L/100km = 100 ÷ km/L. So 20 km/L = 5.0 L/100km, and 8.5 L/100km = 100 ÷ 8.5 = 11.7647 km/L.
Why is lower better for L/100km but higher better for MPG?
L/100km measures fuel consumption (fuel used per distance), so less is better. MPG and km/L measure fuel economy (distance per fuel), so more is better. They describe the same efficiency from opposite directions.
What counts as good fuel economy?
Rough guide for petrol cars: under 5 L/100km (over 47 US MPG) is excellent, typical for hybrids; 6 to 8 L/100km (29 to 39 US MPG) is good, typical for compact cars; 9 to 12 L/100km (20 to 26 US MPG) is average for SUVs; above 13 L/100km (under 18 US MPG) is thirsty, typical for large pickups. Real-world figures are usually 10 to 20 percent worse than lab ratings.
How do I compare a US car advert with a European one?
Convert both to the same unit, usually L/100km. Example: a US advert saying 30 MPG means 7.8405 L/100km, while a European advert saying 5 L/100km means 47.0429 US MPG. The European car is clearly more efficient. Never compare a US MPG number directly with a UK MPG number.
How much fuel will my trip use?
Multiply distance by consumption: litres = distance in km ÷ 100 × L/100km. Example: 500 km at 7.8405 L/100km uses 39.2025 litres. The trip cost section above does this math for you and adds your local fuel price.
What is the difference between km/L and L/100km?
Both are metric, but km/L is distance per fuel (higher is better, common in Japan, India and Brazil) while L/100km is fuel per distance (lower is better, standard in Europe, Australia and Canada). Convert with: km/L = 100 ÷ L/100km.
Can I convert MPG directly to km/L?
Yes: km/L = MPG (US) × 0.4251. So 25 US MPG = 10.6286 km/L. Reverse: MPG (US) = km/L ÷ 0.4251, so 15 km/L = 35.2822 US MPG.
How accurate is this fuel economy converter?
Conversions are exact to the displayed decimals because they use defined constants: 1 US gallon = 3.785411784 litres, 1 imperial gallon = 4.54609 litres, 1 mile = 1.609344 km. Results are shown to 4 decimal places; rounding differences beyond that are negligible for buying or comparing cars.
Free tool by NRTechStudio