MPG to L/100km Converter: Complete Guide to Converting Miles Per Gallon to Liters per 100km
Miles per gallon (MPG) is the standard fuel economy measure in the United States and United Kingdom, where higher numbers indicate greater efficiency. Liters per 100 kilometers (L/100km) is the metric equivalent used across Europe, Australia, and most of the world, where lower numbers indicate greater efficiency. Because MPG and L/100km are inverse relationships, the conversion requires division, not multiplication: L/100km = 235.215 ÷ MPG.
The Formula: L/100km = 235.215 ÷ MPG
The constant 235.215 combines the US gallon (3.785411784 liters) and the exact mile-to-kilometer ratio (1.609344 km/mile): 3.785411784 × 100 ÷ 1.609344 = 235.2145. This single formula converts between the two most widely used fuel economy metrics globally. Note that for UK Imperial MPG, the constant changes to 282.481 because the Imperial gallon = 4.54609 liters.
L/100km = 282.481 ÷ MPG (Imperial)
MPG (US) = 235.215 ÷ L/100km
km/L = MPG × 0.425144
Common references:
20 MPG = 11.76 L/100km (pickup truck)
25 MPG = 9.41 L/100km (average SUV)
30 MPG = 7.84 L/100km (average sedan)
35 MPG = 6.72 L/100km (efficient compact)
40 MPG = 5.88 L/100km (hybrid territory)
50 MPG = 4.70 L/100km (strong hybrid/PHEV)
60 MPG = 3.92 L/100km (top hybrid)
EPA Fuel Economy Ratings Explained
The US EPA provides MPG ratings in three categories: city, highway, and combined. EPA combined = 55% city + 45% highway driving. Real-world fuel economy typically runs 10–20% below EPA ratings due to aggressive driving, climate control, and load. A car rated 35 MPG EPA combined = 6.72 L/100km. In real-world urban driving, expect 28–32 MPG = 7.35–8.40 L/100km. European WLTP ratings are generally closer to real-world performance.
MPG vs L/100km: Which Is Better?
Both systems convey the same information, but MPG can be misleading when comparing improvements. Going from 10 to 20 MPG saves the same fuel as going from 33 to 50 MPG over 10,000 miles, but the L/100km metric makes this clear: 10→20 MPG = 23.5→11.8 L/100km (saving 11.7 L/100km); 33→50 MPG = 7.1→4.7 L/100km (saving only 2.4 L/100km). Improving a gas-guzzler has greater real impact than fine-tuning an already efficient car.
Hybrid and Electric Vehicle Context
Modern hybrids achieve 50–60 MPG (3.9–4.7 L/100km). PHEGs in hybrid mode: 45–55 MPG (4.3–5.2 L/100km). The EPA also rates EVs in MPGe (miles per gallon equivalent), where the energy content of 1 gallon of gasoline (33.7 kWh) is used. A Tesla Model 3: ~140 MPGe = 1.68 L/100km equivalent. This comparison underscores the efficiency advantage of electrification when using equivalent energy metrics.