Fuel Consumption Converter
Comparing a car in Europe and one in the US? There, 6 L/100km is thrifty; here, 40 mpg sounds great. Same idea, opposite scale: lower L/100km is better, higher mpg is better. One wrong mental conversion and you think the wrong car sips fuel.
Quick reference: 30 mpg (US) = 7.84 L/100km. 6 L/100km = 39 mpg (US). Lower L/100km means better efficiency; higher mpg means better efficiency. Use the tool below for any value.
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Quick Reference: Most Searched Fuel Consumption Conversions
Real-World Fuel Consumption Scale
How these numbers relate to everyday lifeWho Uses Fuel Consumption Conversions?
Car buyers (US vs EU)
US stickers show mpg; EU and most of the world show L/100km. If you are comparing a car from another market, you need to convert or you will misread which one is more efficient.
EU car rated 5.5 L/100km = 43 mpg US. US car rated 32 mpg = 7.35 L/100km. The EU car uses less fuel per mile.
Fleet and trip planning
Rental cars and route planners may mix units. Estimating fuel cost for a 500 km trip needs consumption in one consistent unit (L/100km or mpg) and local fuel price per liter or per gallon.
500 km at 7 L/100km = 35 L. At 1.50 EUR/L that is 52.50 EUR. In US: 310 miles at 34 mpg = 9.1 gal.
Emissions and regulations
CO2 rules are often in g/km, which ties directly to L/100km (and fuel type). Converting to mpg helps compare with US CAFE or EPA numbers.
~120 g CO2/km is typical for 5 L/100km petrol. 50 mpg US ≈ 4.7 L/100km ≈ 110 g/km (approx).
Moving between countries
You move from the US to Europe (or the other way) and your mental benchmark is mpg or L/100km. Converting your old car or local ads into the unit you know avoids wrong expectations.
Your old car did 28 mpg US. That is 8.4 L/100km. A new car at 6 L/100km is noticeably more efficient.
Road tests and reviews
Magazines and YouTube use the unit of their audience. Converting real-world test figures lets you compare like with like instead of mixing units.
Review says "we got 6.2 L/100km on the motorway." That is 38 mpg US. Compare with a US-tested car at 36 mpg highway.
Did You Know?
US and UK gallons are different. So US mpg and UK (imperial) mpg are not the same: 30 mpg UK = 25 mpg US. Always check which gallon the sticker or site uses.
Source: EPA / VCA
L/100km is "volume per fixed distance"; mpg is "distance per fixed volume." So one goes down when the other goes up. Formula: L/100km = 235.21 / mpg (US) or 282.48 / mpg (UK).
Source: NIST
EPA and WLTP (European) test cycles differ. A car can show 5.5 L/100km in WLTP and 35 mpg in EPA for similar real-world result — but the numbers are not from the same test, so convert and compare with a grain of salt.
Source: EPA, EU Regulation
Common Mistakes to Avoid
Thinking "higher number is better" for both mpg and L/100km
Higher mpg = better (more miles per gallon). Lower L/100km = better (fewer liters per 100 km). So 40 mpg is efficient; 40 L/100km would be very heavy consumption.
Mixing US and UK mpg without converting
UK gallon is 4.546 L; US gallon is 3.785 L. So 1 UK mpg = 1.2 US mpg (approx). A "40 mpg" UK car is about 33 mpg US. Use the converter with the correct mpg type.
Using km/L and L/100km as if they were the same scale
km/L is "distance per liter" (higher = better). L/100km is "liters per 100 km" (lower = better). 10 km/L = 10 L/100km. So 20 km/L = 5 L/100km.
The two formulas you need
L/100km to mpg (US)
mpg = 235.21 ÷ L/100km
Example: 7 L/100km → 235.21 ÷ 7 = 33.6 mpg
mpg (US) to L/100km
L/100km = 235.21 ÷ mpg
Example: 30 mpg → 235.21 ÷ 30 = 7.84 L/100km
UK mpg uses 282.48 instead of 235.21 (UK gallon is larger).