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Fuel Consumption Converter

Fuel Consumption Converter — Convert km/L, mpg, L/100km & More

Our free online Fuel Consumption Converter lets you instantly convert between 36+ units of fuel consumption and fuel economy — from everyday km per liter and miles per gallon to metric and imperial variants. Whether you need to convert mpg to L/100km, km/L to mpg, miles per gallon (US) to miles per gallon (UK), or liter/100 km to mile/gallon, this tool delivers instant and accurate results.

Fuel consumption (or fuel economy) measures how much fuel a vehicle uses per distance traveled, or alternatively how far it can go per unit of fuel. Two main conventions exist:

  • Fuel economy (distance per volume): km/L, mile/gallon (US), mile/gallon (UK), nautical mile/gallon — higher is more efficient
  • Fuel consumption (volume per distance): L/100 km, gallon/100 miles — lower is more efficient
  • SI metric: meter/liter (m/L), kilometer/liter (km/L), liter/100 km
  • US customary: mile/gallon (US), gallon (US)/mile, gallon (US)/100 miles
  • UK imperial: mile/gallon (UK), gallon (UK)/mile, gallon (UK)/100 miles

All conversions use standardized factors, making this tool reliable for automotive engineering, fleet management, trip planning, and comparing vehicles across different regional standards.

Common Fuel Consumption Conversion Reference

Here are the most frequently used fuel consumption conversions for quick reference:

  • 1 km/L = 2.35215 mpg (US) = 2.82481 mpg (UK) = 100 L/100km (reciprocal)
  • 1 mpg (US) = 0.425144 km/L = 1.20095 mpg (UK) = 235.215 L/100km (reciprocal)
  • 1 mpg (UK) = 0.354006 km/L = 0.832674 mpg (US)
  • 10 L/100 km = 10 km/L (reciprocal) ≈ 23.52 mpg (US)
  • 30 mpg (US) ≈ 12.75 km/L ≈ 7.84 L/100 km
  • 50 mpg (US) ≈ 21.26 km/L ≈ 4.70 L/100 km
  • 1 nautical mile/gallon (US) = 0.489576 km/L
  • 1 mile/gallon (US) = 0.264172 km/L (distance per volume)

Frequently Asked Questions — Fuel Consumption Converter

Question: How do I use the Fuel Consumption Converter?

Answer: Select the unit you are converting from in the left list and the unit to convert to in the right list, then type your value. The result appears instantly across all listed units.

Question: What is the difference between fuel consumption and fuel economy?

Answer: Fuel economy measures how far you can travel per unit of fuel (e.g., mpg, km/L) — higher values mean better efficiency. Fuel consumption measures how much fuel is used per unit of distance (e.g., L/100 km, gal/100 mi) — lower values mean better efficiency. They are reciprocals of each other.

Question: How do I convert mpg to L/100km?

Answer: Use the formula: L/100 km = 235.215 ÷ mpg (US). For example, 30 mpg (US) = 235.215 ÷ 30 = 7.84 L/100 km. This is because the units are reciprocals and involve both unit system conversions.

Question: What is the difference between US mpg and UK mpg?

Answer: The US gallon (3.78541 L) is smaller than the UK Imperial gallon (4.54609 L). So 1 mpg (UK) ≈ 1.20095 mpg (US). A car rated at 40 mpg (UK) would only achieve about 33.4 mpg (US).

Question: How do I convert km/L to mpg?

Answer: Multiply km/L by 2.35215 to get mpg (US). For example, 15 km/L × 2.35215 = 35.28 mpg (US). To convert to mpg (UK), multiply km/L by 2.82481.

Question: What is a good fuel economy in L/100 km?

Answer: For passenger cars, under 6 L/100 km is considered excellent fuel economy. 6–8 L/100 km is good, 8–10 L/100 km is average, and over 10 L/100 km is below average. Hybrids and EVs effectively achieve 2–4 L/100 km equivalent.

Question: Why does fuel consumption conversion use reciprocals?

Answer: Fuel economy (distance/volume, like mpg) and fuel consumption (volume/distance, like L/100 km) are reciprocals of each other. Converting between them requires dividing the constant (e.g., 235.215 for US gallon/mile to L/km) by the given value, not multiplying.

Question: How accurate are the fuel consumption conversions in this tool?

Answer: All conversions use internationally standardized conversion factors with up to 12 significant digits of precision, suitable for automotive engineering, fleet management, and consumer vehicle comparisons.