Two Different Perspectives
There are two main ways the world measures fuel economy:
- Distance per Volume (MPG): How far can I go on one gallon?
- Volume per Distance (L/100km): How much fuel do I need to go 100km?
Why L/100km is Technically Better
Most engineers prefer the Liters per 100km (L/100km) metric because it's linear.
- If you improve from 10 MPG to 20 MPG, you save a lot of fuel.
- If you improve from 40 MPG to 50 MPG, you save very little.
In L/100km, the savings are always apparent at a glance.
The Formulas
- To get L/100km from MPG (US): 235.215 ÷ MPG
- To get MPG (US) from L/100km: 235.215 ÷ L/100km
Key Takeaways
- US Gallons and UK Gallons are different!
- Higher MPG is better
- Lower L/100km is better