Check My Car's CO2 Emissions by Reg

Check my car's CO2 emissions by reg

Enter the registration in the search box above. The free check shows the CO2 emissions figure in grams per kilometre recorded for the vehicle, its fuel type, engine size and Euro status, with its tax and MOT status and the full MOT history. The full report adds the road tax band and what the tax costs for 12 and 6 months.

Why the CO2 figure matters

• Car tax. For cars first registered between March 2001 and March 2017, the yearly tax is set by the CO2 band. For cars registered from April 2017, CO2 sets the first-year rate, then a standard rate applies.
• Company car tax. Benefit-in-kind rates rise with CO2, so the figure decides what a company car costs its driver.
• Clean air zones. ULEZ and other zones use the Euro standard rather than CO2, but the two go together on the record; see the ULEZ check and the clean air zone check.
• Running costs. CO2 tracks fuel consumption: a lower figure usually means better mpg.

Emissions checker: the CO2 figure and the MOT emissions test are different things

"Car emissions check" means two different checks, and it helps to know which one you need:

• The recorded CO2 figure is a number fixed when the car was new, from the manufacturer's official test. It never changes, and it's what tax bands, company car tax and this page are about. The free check shows it from the DVLA record.
• The MOT emissions test measures what comes out of the exhaust on the day: carbon monoxide, hydrocarbons and lambda for petrol cars, smoke opacity for diesels. It is a pass-or-fail item in every MOT, and a car that fails it usually has a worn catalytic converter, a faulty sensor, a blocked diesel particulate filter or a tuning problem. The free MOT history check lists every test since 2005, including emissions failures and advisories.

Neither is the Euro standard, which is the third "emissions" question people ask. The Euro status (Euro 4, Euro 6 and so on) is the standard the car was built to, and it is what decides ULEZ and clean air zone charges. The free check shows it where the DVLA holds it.

What tax band is my car? CO2 bands for 2001 to 2017 cars

Band A cars registered before April 2017 paid nothing until April 2025, when a £20 rate applied to them. The rates for each band change with the Budget; our car tax calculator explains the current rates, and the full report shows the cost for the exact car.

Cars registered from April 2017

CO2 sets the first-year rate only, from a low figure for the cleanest cars to over £5,000 for the highest emitters. From the second year every car pays the same standard rate (£195 in 2025/26), plus a supplement for five years if the list price was over £40,000. Electric cars joined the system in April 2025.

Typical CO2 figures: is my car's number high or low?

These are broad ranges, not rules: a 2010 figure and a 2020 figure for the same model aren't directly comparable because of the test change below, and a plug-in hybrid's official number assumes it is charged regularly.

Where the CO2 figure comes from

The figure on the DVLA record is the manufacturer's official test result for that exact variant, recorded at first registration. Cars registered from September 2018 were tested under the WLTP procedure, which gives higher, more realistic figures than the older NEDC test; a 2019 car can show a higher CO2 than the same model from 2017 without using more fuel. Imported cars sometimes have no CO2 recorded, in which case tax is set by engine size instead.

Can I lower my car's CO2 figure?

Not the recorded one: it is fixed at first registration and the DVLA won't change it, so the tax band stays whatever you do to the car. What you can lower is the fuel you actually burn, and with it the cost: correct tyre pressures, less weight and roof clutter, smooth driving and keeping the engine serviced all help, and a healthy exhaust system keeps the MOT emissions test in hand. If the CO2 figure matters for the tax you'll pay, the answer is the car you choose, not what you do to it: compare figures across models on our make and model pages before you buy.

What the free check shows, and what the full report adds

CO2 emissions check FAQs