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Mpg to L Per 100km Converter

Convert fuel economy between miles per gallon and liters per 100 kilometers. Enter values for instant results with step-by-step formulas.

Reviewed by Manoj Kumar, Mathematics Educator

Reviewed by Manoj Kumar, Mathematics Educator

Formula

L/100km = 235.215 / MPG (US)

The conversion uses the constant 235.215, derived from (100 x 3.78541 liters/gallon) / 1.60934 km/mile. For Imperial MPG, the constant is 282.481. MPG and L/100km have an inverse relationship: higher MPG means lower L/100km. To convert km/L to L/100km, divide 100 by the km/L value.

Worked Examples

Example 1: Sedan Fuel Economy Comparison

Problem:A car is rated at 32 MPG (US). Convert to L/100km and calculate annual fuel cost for 15,000 miles at $3.60/gallon.

Solution:L/100km = 235.215 / 32 = 7.35 L/100km\nImperial MPG = 32 / 0.832674 = 38.43 MPG (UK)\nkm/L = 100 / 7.35 = 13.60 km/L\nAnnual gallons = 15,000 / 32 = 468.75 gallons\nAnnual fuel cost = 468.75 x $3.60 = $1,687.50\nCost per mile = $3.60 / 32 = $0.1125/mile

Result:32 MPG = 7.35 L/100km = 38.43 Imperial MPG | Annual cost: $1,687.50 for 15,000 miles

Example 2: European Car Specification Conversion

Problem:A European car is rated at 5.2 L/100km. Convert to US MPG and Imperial MPG.

Solution:US MPG = 235.215 / 5.2 = 45.23 MPG\nImperial MPG = 282.481 / 5.2 = 54.32 MPG (UK)\nkm/L = 100 / 5.2 = 19.23 km/L\nGallons per 100 miles = (5.2 x 1.60934) / 3.78541 = 2.21 gal/100mi\nAt 12,000 mi/yr: 12,000 / 45.23 = 265.3 gallons/year

Result:5.2 L/100km = 45.23 US MPG = 54.32 Imperial MPG = 19.23 km/L

Frequently Asked Questions

How do I convert MPG to liters per 100 km?

To convert miles per gallon (US) to liters per 100 kilometers, divide 235.215 by the MPG value. For example, 30 MPG equals 235.215 divided by 30 = 7.84 L/100km. This formula works because one US gallon equals 3.78541 liters and one mile equals 1.60934 kilometers. The constant 235.215 is derived from (100 x 3.78541) / 1.60934. Note that MPG and L/100km have an inverse relationship: as MPG increases, L/100km decreases. A car rated at 40 MPG uses 5.88 L/100km, while a car at 20 MPG uses 11.76 L/100km. This inverse relationship means equal MPG improvements save more fuel at lower MPG values.

What is the difference between US MPG and Imperial MPG?

US MPG and Imperial (UK) MPG differ because US gallons and Imperial gallons are different sizes. One US gallon equals 3.78541 liters, while one Imperial gallon equals 4.54609 liters, making the Imperial gallon about 20 percent larger. As a result, Imperial MPG figures are always higher than US MPG for the same vehicle. To convert US MPG to Imperial MPG, divide by 0.832674 (or multiply by 1.201). A car rated at 30 US MPG would be rated at approximately 36 Imperial MPG. This difference can cause significant confusion when comparing fuel economy figures between American and British automotive publications or when purchasing imported vehicles.

Why do some countries use L/100km instead of MPG?

Most countries outside the United States use liters per 100 kilometers because it is based on the metric system and provides a more intuitive understanding of fuel consumption. L/100km measures fuel consumed per distance rather than distance traveled per fuel unit, making it easier to calculate trip fuel costs: simply multiply L/100km by the distance in hundreds of kilometers and then by the fuel price. L/100km also has a linear relationship with fuel consumption, meaning going from 10 to 8 L/100km saves the same amount of fuel as going from 6 to 4 L/100km. In contrast, MPG has a nonlinear relationship where improving from 15 to 20 MPG saves more fuel than improving from 35 to 40 MPG.

What is considered good fuel economy in both MPG and L/100km?

Good fuel economy standards vary by vehicle type and region. For compact cars, 30 to 40 MPG (7.8 to 5.9 L/100km) is considered good, while hybrids achieve 40 to 60 MPG (5.9 to 3.9 L/100km). Midsize sedans averaging 25 to 30 MPG (9.4 to 7.8 L/100km) are acceptable. SUVs and trucks at 20 to 25 MPG (11.8 to 9.4 L/100km) are considered efficient for their class. Electric vehicles expressed in MPGe (miles per gallon equivalent) often exceed 100 MPGe. The US fleet average fuel economy standard (CAFE) requires approximately 49 MPG for passenger cars by 2026. European standards target approximately 4.1 L/100km (57.4 MPG) for new passenger cars.

References

Reviewed by Manoj Kumar, Mathematics Educator · Editorial policy