MPG check
What a car's official fuel economy figures mean and where to find them. Buying one? The £15 report shows its CO₂, fuel type and engine with finance, write-off, theft and mileage checks. It does not include MPG figures.
£15 vehicle history report · Instant results
What the three figures mean
Official fuel economy is measured in a laboratory, on a rolling road, to a fixed test cycle. Each figure covers a different part of that test.
Combined
The whole test averaged out. This is the headline figure in adverts and the best single number for comparing cars.
Urban
The slow, stop-start part of the test, starting from cold. Expect the lowest figure here, especially from petrol engines.
Extra urban
The faster, steadier part of the test. Usually the highest figure, and the closest to motorway and A-road driving.
Why real-world MPG is usually lower
Official figures are made to compare cars fairly, not to predict what you will get. The test is run indoors, at set speeds, with no roof bars, heater or passengers, so most drivers see less.
Since September 2017 new models have been tested under WLTP, a longer and faster cycle than the older NEDC test. WLTP figures are generally lower and closer to real driving, so compare cars tested under the same system where you can.
Short trips, cold weather, heavy loads, underinflated tyres and motorway speeds above 70 mph all cut economy. A diesel or hybrid used only for short runs can fall well short of its figures.
MPG and L/100km
UK adverts use miles per gallon, European spec sheets use litres per 100 km. Higher mpg is better; lower L/100km is better.
| MPG | L/100km |
|---|---|
| 30 mpg | 9.4 L/100km |
| 40 mpg | 7.1 L/100km |
| 50 mpg | 5.6 L/100km |
| 60 mpg | 4.7 L/100km |
To convert, divide 282.5 by the figure. UK mpg uses the imperial gallon (4.546 litres), so US mpg figures look lower for the same car.
Before you rely on the figure
- Plug-in hybrids. Their official mpg assumes a charged battery for part of the test. With a flat battery on a long run they return far less.
- Electric cars have no mpg. The electric car check explains what to look at instead.
- This car, not the model. The figures belong to the model and variant as built. Tyres, servicing and how it has been driven all affect the car in front of you.
- Official source. The Vehicle Certification Agency publishes official fuel economy and CO₂ figures for new cars sold in the UK on its car fuel data site, free.
MPG check FAQs
How do I check a car's MPG?
Look up the model on the Vehicle Certification Agency's car fuel data site or in the manufacturer's brochure. The Carpeep report does not include MPG figures. It shows the car's CO₂, fuel type and engine with its finance, write-off, theft and mileage history.
Is official MPG accurate?
It is accurate for comparing cars, because every car sits the same test. It is not a promise of what you will get. Most drivers see less, and the gap is usually bigger on older NEDC figures than on WLTP ones.
What is a good MPG for a used car?
It depends on the type of car. Compare the combined figure against similar cars of the same size and fuel, ideally tested under the same system (NEDC or WLTP), rather than against a single target number.
Does MPG affect car tax?
Not directly. Road tax for cars registered from March 2001 to March 2017 is set by CO₂, and for newer cars CO₂ sets the first year's rate. CO₂ rises as economy falls. See car tax bands or check the car's actual tax with the car tax check.
Does the Carpeep report include MPG?
No. The report covers the car's history and recorded specification: finance, write-offs, theft, mileage, MOT, keepers, CO₂, fuel type and engine. For official fuel economy, use the Vehicle Certification Agency's car fuel data or the manufacturer's figures.
More vehicle checks
Already found one?
Check its finance, write-off, theft, mileage and keeper history with a £15 vehicle history report.
In the report, the specification and registration details come from DVLA records and our vehicle data provider, and MOT history from the DVSA. Carpeep is not affiliated with the DVLA or DVSA.