Fuel Economy Converter – Convert MPG & L/100km

This fuel economy converter routes every input through exact definitions — L/100 km = 235.214583 ÷ mpg (a reciprocal, not a factor). Enter a value, pick the source and target units, and the result appears instantly with the factor applied shown beside it. Miles per gallon and liters per 100 km disagree in direction as well as units: a higher mpg number means better economy, while a higher L/100 km figure means worse — the scales run opposite ways. The bridge is a reciprocal, not a factor: L/100 km = 235.214583 ÷ mpg, derived from one US gallon (3.7854118 L) crossing 1.609344 km per mile, so division — never multiplication — converts between them. A mini table of the head factor makes spot-checks immediate: 10 mpg = 23.52 L/100km; 25 mpg = 9.41 L/100km; 40 mpg = 5.88 L/100km; 50 mpg = 4.70 L/100km; 60 mpg = 3.92 L/100km. Anchors translate instantly: 30 mpg ≈ 7.8 L/100 km, and the popular European 5.0 L/100 km hatchback would rate about 47 mpg US.

1. 1

   Step 1

   Enter the value you want to convert

2. 2

   Step 2

   Select the source unit you are converting from

3. 3

   Step 3

   Select the target unit you want as the result

4. 4

   Step 4

   Read the exact result, then swap or copy as needed

• 1

  Memorize 235.214583 = the mpg ↔ L/100 km pivot

• 2

  Quick anchors: 30 mpg ≈ 7.8, 40 mpg ≈ 5.9 L/100 km

• 3

  UK mpg: multiply by 1.20095 to state US mpg

• 4

  EU labels now show L/100 km — divide 282.481 by it for UK mpg

• Multiplying mpg by a factor instead of dividing 235.214583 by it

• Reading better economy into a higher L/100 km figure — the scale runs backwards

• Converting UK-mpg figures with the US-gallon constant