What's the difference between US MPG and UK MPG?

US MPG (Miles Per Gallon) uses the US gallon (3.785 liters), while UK MPG uses the Imperial gallon (4.546 liters). Since the UK gallon is about 20% larger, UK MPG values are approximately 20% higher than US MPG for the same vehicle. For example, 30 MPG (US) equals approximately 36 MPG (UK).

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

L/100km (Liters per 100 kilometers) is the standard in most countries using the metric system, including Europe, Australia, and Canada. It directly measures fuel consumption rather than distance per fuel unit, making it easier to calculate fuel costs for trips. Lower L/100km values indicate better efficiency.

How do I convert MPG to L/100km?

To convert MPG (US) to L/100km, divide 235.214 by the MPG value. For example, 30 MPG (US) = 235.214 ÷ 30 = 7.84 L/100km. For UK MPG, divide 282.481 by the MPG value. Our converter handles these calculations automatically for both US and UK gallons.

What is considered good fuel efficiency?

Good fuel efficiency varies by vehicle type. For compact cars, 35+ MPG (US) or under 7 L/100km is excellent. Mid-size sedans achieving 30+ MPG (US) or under 8 L/100km are efficient. SUVs with 25+ MPG (US) or under 10 L/100km are considered good. Hybrid vehicles often exceed 50 MPG (US) or achieve under 5 L/100km.

Can I use this converter for electric vehicles?

This converter is designed for traditional fuel-powered vehicles. Electric vehicles use different efficiency metrics like MPGe (Miles Per Gallon equivalent) or kWh/100km. However, you can use this tool to compare the fuel efficiency of hybrid vehicles that use both gasoline and electric power.

How accurate are the fuel efficiency conversions?

Our converter uses precise conversion factors: 1 US gallon = 3.785411784 liters and 1 UK gallon = 4.54609 liters. Results are rounded to two decimal places for practical use. The conversions are mathematically accurate and suitable for all vehicle comparison, trip planning, and fuel cost estimation purposes.

Fuel Efficiency Converter

Convert fuel efficiency between MPG (US/UK), L/100km, and km/L for accurate vehicle comparison and trip planning

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Quick Presets

Common fuel efficiency values for quick testing

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Enter value, choose units, and run conversion in one step.

Fuel Efficiency Value

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How it works: Converts fuel efficiency between MPG (US), MPG (UK), L/100km, and km/L. US and UK gallons differ in size (US: 3.785L, UK: 4.546L).

Fuel Efficiency Reference Chart

Common vehicle fuel efficiency comparisons

Vehicle Type	MPG (US)	MPG (UK)	L/100km	km/L
Compact Car (Efficient)	40	48	5.9	17.0
Mid-Size Sedan	30	36	7.8	12.8
SUV (Average)	25	30	9.4	10.6
Pickup Truck	20	24	11.8	8.5
Hybrid Vehicle	50	60	4.7	21.3
Sports Car	18	22	13.1	7.7

🚗 Fuel Efficiency Tips

• Lower L/100km values and higher MPG values indicate better fuel efficiency
• US and UK gallons differ in size (US: 3.785L, UK: 4.546L), so UK MPG values are approximately 20% higher than US MPG for the same vehicle
• Maintain proper tire pressure for optimal fuel economy
• Avoid aggressive acceleration and braking
• Remove excess weight from your vehicle
• Use cruise control on highways when appropriate
• Keep your engine properly maintained and tuned
• Combine errands to reduce cold starts

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