L/100km to MPG: reading a European fuel figure in American terms
What this conversion does
It restates a litres-per-100-kilometres figure as US miles per gallon. European manufacturers, and the WLTP test cycle that gives their official numbers, publish fuel consumption per fixed distance; American buyers and the EPA think in distance per fixed volume. Converting between them is the first step in any transatlantic car comparison.
Why MPG rises as L/100km falls
The two units are reciprocals, joined by the constant 235.2 — 100 km expressed in the distance a single US gallon will carry you, using the exact mile of 1.609344 km and the exact US gallon of 3.785411784 litres. Dividing 235.2 by the L/100km figure gives MPG. A 5.0 L/100km car is therefore 47.0 MPG, and a 10.0 L/100km car is 23.5 MPG: halving the consumption doubles the mileage.
L/100km to MPG (US) conversion table
Typical European consumption figures with their US equivalent. Small differences at the efficient end matter a great deal: the step from 5 to 4 L/100km is worth almost 12 MPG, while the step from 12 to 11 is worth under 2.
| Litres per 100 km | Miles per gallon (US) |
|---|---|
| 2 L/100km | 117.6073 mpg |
| 3 L/100km | 78.4049 mpg |
| 4 L/100km | 58.8036 mpg |
| 5 L/100km | 47.0429 mpg |
| 6 L/100km | 39.2024 mpg |
| 7 L/100km | 33.6021 mpg |
| 8 L/100km | 29.4018 mpg |
| 9 L/100km | 26.1350 mpg |
| 10 L/100km | 23.5215 mpg |
| 12 L/100km | 19.6012 mpg |
| 15 L/100km | 15.6810 mpg |
| 20 L/100km | 11.7607 mpg |
The trap in the efficient end of the scale
Because the relationship is reciprocal, equal steps in L/100km are worth wildly unequal steps in MPG. Improving from 6.0 to 5.0 L/100km gains 7.8 MPG; improving from 3.0 to 2.0 L/100km gains 39.2 MPG for the same one-litre saving. When a manufacturer boasts about a large MPG gain, check where on the scale it happened before assuming the fuel saving is equally large.
Comparing official figures fairly
European WLTP figures and US EPA figures are produced by different test cycles, so a converted number still overstates or understates real-world economy. The gap usually runs 10–20% in favour of the laboratory. Convert for a fair order-of-magnitude comparison, then look for real-world owner data before making a decision.
Frequently asked questions
How do I convert L/100km to MPG in my head?
Divide 235 by the consumption figure. For 5 L/100km that is 235 ÷ 5 = 47 MPG, and for 8 L/100km it is 235 ÷ 8 ≈ 29 MPG. The trick works because both the mile and the US gallon are fixed constants, so 235.2 is always the numerator for US gallons.
Does this use US or imperial gallons?
US gallons. For imperial MPG the constant is 282.5 instead of 235.2, since a UK gallon holds 4.54609 litres rather than 3.785411784. That makes an imperial figure about 20% higher for the same car.
Why do European cars quote consumption instead of mileage?
Per-distance consumption scales linearly with the fuel you actually buy: driving twice as far burns twice the litres, so a trip cost is one multiplication. Distance-per-volume scales inversely, which makes trip estimates harder. It is a presentation choice rather than a difference in the underlying efficiency.
What is a good L/100km figure?
As a rough guide, under 5.0 L/100km is very efficient and typical of modern hybrids, 5.0–7.0 is a normal compact car, 7.0–10.0 covers larger petrol cars and crossovers, and above 10.0 is a large or performance vehicle. Convert any of these with the table above to place a car on the US MPG scale.
Can consumption be zero?
No, and the tool rejects it. Zero litres per 100 km would mean infinite mileage, which no combustion vehicle achieves, so the result is undefined. Enter a positive figure; values below about 1.5 L/100km are already beyond any production car.