What is a good mpg for a car today?
For a petrol car sold in the US, anything above 35 mpg (US) combined is good and above 45 is excellent, with the second figure almost always meaning a hybrid. In the UK, above 50 mpg (imperial) on the WLTP cycle is good for petrol and above 60 is excellent. In metric terms, under 6 L/100km is good and under 5 is excellent. The EPA's Automotive Trends Report puts the average new vehicle sold in America at roughly 27 mpg, dragged down by the popularity of trucks and SUVs.
Those thresholds have moved. Twenty years ago 30 mpg (US) was a strong result for a family sedan; today several hybrids exceed 50. The floor has risen too: very few new cars sold in 2026 score under 20 mpg (US) combined, where a generation ago most large SUVs did.
How do the benchmarks differ by type of car?
Small hatchbacks and city cars: 35 to 42 mpg (US), 5.6 to 6.7 L/100km. The best non-hybrid petrol cars in this class reach the low 40s on the EPA cycle; a hybrid version of the same car reaches 50 or more.
Compact and mid-size sedans: 30 to 36 mpg (US) for petrol, 45 to 52 for hybrids. A Toyota Camry or Honda Accord hybrid at close to 50 mpg (US), or 4.7 L/100km, is the current benchmark for a family car that is not a plug-in.
Compact SUVs and crossovers: 26 to 32 mpg (US) for petrol, 35 to 40 for hybrids. Mid-size and three-row SUVs: 20 to 26 for petrol, 30 to 36 for hybrids. The hybrid premium is largest in this class, because these vehicles spend their lives in the stop-start driving where a hybrid recovers most energy.
Pickups and large body-on-frame SUVs: 17 to 23 mpg (US), or 10 to 14 L/100km. A full-size pickup at 22 mpg combined is good for the class; at 25 with a hybrid powertrain it is exceptional. Diesel versions of the same trucks add 3 to 5 mpg.
Performance cars: 18 to 25 mpg (US). Nobody buys them for economy, but a modern turbocharged sports sedan at 25 mpg would have been unthinkable for its power output in 2006.
Why are UK and European figures always higher?
Two reasons, one of them a unit. A British mpg figure uses the imperial gallon of 4.54609 litres, so it reads 20.095% higher than the same efficiency in US gallons. A UK car at 55 mpg is a 45.8 mpg (US) car, which the UK to L/100km converter confirms as 5.14 L/100km. Remove the gallon and the difference shrinks.
The rest is the test. WLTP produces figures around 10 to 20% above the EPA's for the same car. So a UK figure of 55 mpg describes a car that would score somewhere near 40 mpg on an American window sticker. Neither figure is wrong; they answer different questions on different scales. The ratings guide sets out what each test measures.
European benchmarks in L/100km, for reference: under 5 is excellent for a petrol car on WLTP, 5 to 6 is good, 6 to 7.5 is ordinary, and above 8 is a large SUV or a performance car. Diesels sit roughly a litre lower across the board.
What is good fuel economy in km/L?
For markets that use kilometres per litre, above 15 km/L is good for a petrol car and above 20 is excellent. A figure of 15 km/L is 35.3 mpg (US) or 6.67 L/100km. Japanese WLTC catalogue figures for small hybrids reach 30 km/L and beyond; Indian ARAI figures for small petrol hatchbacks commonly sit at 20 to 24 kmpl, with real-world results from owners typically 15 to 25% lower.
Diesel cars in India and South East Asia return 18 to 25 km/L in owners' hands. Large SUVs and pickups, which are less common in those markets but growing, sit at 8 to 12 km/L. The MPG to km/L converter turns any of the US benchmarks above into this unit.
Is diesel still more economical than petrol?
Yes, by about 20 to 30% in fuel volume, because diesel contains more energy per litre and diesel engines convert it more efficiently. A diesel family car at 4.5 L/100km against a petrol equivalent at 5.8 is typical. The gap has narrowed since 2015 as petrol engines gained direct injection and hybridisation, and diesel's share of new car sales in Europe has fallen from over half to under a fifth.
The economy advantage is real; whether it is worth having depends on how far you drive, the price gap at the pump in your country, and local rules on older diesels in city centres. A diesel driven 8,000 miles a year rarely recovers its higher purchase price in fuel savings.
How should I judge a figure I have been given?
First find out the unit and the gallon: mpg (US), mpg (UK), L/100km or km/L. Second, find out the test: EPA, WLTP, NEDC, JC08, WLTC or ARAI, or whether it is an owner's real-world measurement. Third, convert it to the unit you think in with the converter and compare against the class benchmarks above, remembering that a WLTP or ARAI figure is optimistic.
A figure that survives all three checks and still looks good is good. A figure that looks remarkable usually has a gallon or a gentle test cycle behind it, and the real-world MPG guide covers the size of that gap.