Converter

Fuel Economy Converter

Convert between MPG (US), MPG (UK), L/100km, and km/L. Compare US and European fuel economy standards side by side.

Quick Answer

30 MPG (US) = 36 MPG (UK) = 7.84 L/100km = 12.75 km/L. To convert MPG to L/100km: divide 235.215 by your MPG value. Higher MPG = lower L/100km = better fuel economy.

Convert Fuel Economy

Enter a value and select units. Note: L/100km is an inverse scale (lower = more efficient).

30 MPG (US)
7.84 L/100km

All Equivalents

Miles per Gallon (US) (MPG (US))30
Miles per Gallon (UK) (MPG (UK))36.03
Liters per 100 km (L/100km)7.84
Kilometers per Liter (km/L)12.75

Vehicle Fuel Economy Comparison

How different vehicle types compare in US and EU measurements.

Vehicle TypeMPG (US)MPG (UK)L/100kmkm/L
Large SUV / Truck
Ford F-150, Chevy Tahoe class
1821.6213.077.65
Midsize Sedan
Toyota Camry, Honda Accord class
3238.437.3513.6
Compact Car
Honda Civic, Toyota Corolla class
3643.236.5315.31
Hybrid
Toyota Prius, Honda Insight class
5060.054.721.26
Plug-in Hybrid
Combined MPGe (Toyota RAV4 Prime class)
90108.092.6138.26

About This Tool

The Fuel Economy Converter helps you translate fuel efficiency ratings between the four most common measurement systems used worldwide. Whether you are comparing vehicles listed in different markets, calculating trip fuel costs, or understanding international fuel economy standards, this tool provides instant conversions with a comparison reference table.

US vs European Fuel Economy Standards

The US measures fuel economy in miles per gallon (MPG), where higher is better. Europe and most other countries use liters per 100 kilometers (L/100km), where lower is better. This inverse relationship can be confusing: a car rated at 30 MPG (US) uses 7.84 L/100km, while a car rated at 50 MPG (US) uses only 4.7 L/100km. The EU has been tightening fleet-wide emission targets, with a 2025 target of approximately 4.1 L/100km (57 MPG) for new passenger cars.

Why US and UK MPG Are Different

The US gallon (3.785 liters) is smaller than the Imperial gallon (4.546 liters) used in the UK. This means UK MPG numbers are always about 20% higher than US MPG for the same vehicle. A car rated at 30 MPG in the US would be rated at approximately 36 MPG in the UK. Always verify which gallon standard is being used when comparing international fuel economy figures.

The Non-Linear Nature of Fuel Savings

Improving from 15 to 20 MPG saves more fuel than improving from 35 to 40 MPG for the same distance driven. This is because MPG has a non-linear relationship with fuel consumption. Going from 15 to 20 MPG over 10,000 miles saves 167 gallons, while going from 35 to 40 MPG saves only 36 gallons. L/100km is more intuitive for comparing fuel savings because it scales linearly with consumption.

Frequently Asked Questions

How do I convert MPG to L/100km?
Divide 235.215 by the MPG (US) value. For example, 30 MPG = 235.215 / 30 = 7.84 L/100km. For MPG (UK), divide 282.481 instead. The relationship is inverse: higher MPG means lower L/100km and vice versa. A car getting 25 MPG (US) uses 9.41 L/100km, while 40 MPG (US) uses only 5.88 L/100km.
What is the difference between US MPG and UK MPG?
The difference is in the gallon size. A US gallon is 3.785 liters, while an Imperial (UK) gallon is 4.546 liters — about 20% larger. This means the same car will always have a higher UK MPG number than US MPG. For example, 30 MPG (US) equals approximately 36 MPG (UK). When comparing fuel economy, always check which gallon is being used.
Why does Europe use L/100km instead of MPG?
Europe uses L/100km because it directly tells you how much fuel you will consume for a given distance, making it easier to calculate trip fuel costs. If your car uses 6 L/100km and you are driving 300 km, you need 18 liters. With MPG, you need an extra division step. L/100km also uses metric units, which are standard throughout Europe and most of the world.
What is considered good fuel economy?
In the US, the average new car achieves about 27.5 MPG (combined). Above 30 MPG (US) / below 7.8 L/100km is considered good. Above 40 MPG / below 5.9 L/100km is excellent (typical for hybrids). Above 50 MPG / below 4.7 L/100km is exceptional (plug-in hybrids in electric mode). EVs are rated in MPGe (miles per gallon equivalent), often exceeding 100 MPGe.
How do I calculate annual fuel cost from MPG?
Divide your annual miles by your MPG to get gallons used, then multiply by gas price. Example: 12,000 miles per year at 30 MPG with gas at $3.50/gallon: 12,000 / 30 = 400 gallons, times $3.50 = $1,400 per year. Each 5 MPG improvement saves roughly $200-400 per year depending on driving habits and fuel prices.

Was this tool helpful?