CO2 output in grams per kilometre
The figure that sets your first year road tax and, for company car drivers, your benefit in kind band.
Car Emissions Check
Enter the number plate to continue.
Instant FREE
Car Emissions Check
Enter a registration to see the CO2 output, Euro emission standard and fuel type recorded for any UK vehicle. Those three figures decide what you pay in road tax and whether you are charged to drive into a city.
Recorded emissionsRecorded g/km value where available
Fuel typePetrol, diesel, electric or other
Free sourceUses existing vehicle data
What our emissions check shows
Euro emission standard
Euro 4, 5, 6 or newer. This is the number that decides clean air zone charges, and it is the one almost no advert mentions.
Fuel type and engine size
Petrol, diesel, hybrid or electric, with capacity. Petrol and diesel are held to very different standards.
Date of first registration
The fallback when a Euro standard is not recorded, since the thresholds are tied to registration dates.
Why emissions data affects what you pay
Two cars that look identical can cost very differently to own. The CO2 and Euro standard on record decide what you pay before you've even driven the car.
- Check CO2 output and road tax band
- See the figure that sets your first year VED rate.
- Confirm the Euro emissions standard Know before you're charged for entering a clean air zone.
- See NOx and particulate levels The pollution data behind every emissions rating.
- Check clean air zone and ULEZ charges
- Avoid a daily charge you didn't know was coming.
- Protect resale value Non-compliant diesels lose value fast as more cities add charging zones.
- Compare running and insurance costs.
1
Road tax
CO2 sets the first year rate and, for cars registered before April 2017, the standard rate too. Current tax status sits on the road tax check page.
2
Clean air zone charges
ULEZ, CAZ and LEZ schemes all charge on the Euro standard rather than CO2. If you are asking whether a specific car will be charged, the clean air zone checker answers it directly.
3
Resale value
A non compliant diesel is worth measurably less than a compliant one, and the gap widens each time another city announces a scheme. Run a car valuation alongside this check before you agree a price.
4
Running costs
Emissions correlate with fuel consumption and often with insurance banding. The insurance group check and the car spec check fill in the rest of the picture.
Check recorded car emissions by registration
REGUP's free car emissions check shows the CO2 figure held in available vehicle records, normally expressed in grams per kilometre, together with fuel type and other emissions details when supplied. Enter the current UK number plate to start.
What the emissions figure means
CO2 g/km is a standardised figure associated with the vehicle model and registration record. It helps compare the carbon output of different vehicles and can be relevant to vehicle tax rules, company-car decisions and general running-cost comparisons.
The recorded figure is not a live exhaust test. Actual emissions and fuel use vary with maintenance, driving style, traffic, load, temperature and vehicle condition. A missing CO2 value is shown as Not available.
Car emissions, road tax and clean-air zones
CO2 has been used in different UK vehicle-tax systems, but tax depends on the first-registration date, fuel type, list price and the rules that apply to that vehicle. Use the separate vehicle tax band and running-cost check for a clearer estimate.
ULEZ and other clean-air-zone rules are not decided by CO2 alone. They commonly rely on Euro emissions standards, vehicle class, fuel and local rules. Use the dedicated ULEZ check and confirm final charging decisions with the relevant authority.
What euro is my car?
The Euro standard is the emissions rule a vehicle was built to meet. Each version tightened the limits on NOx and particulates.
Euro 4 petrol, broadly cars registered from January 2006.
Euro 5 diesel, broadly from January 2011.
Euro 6 diesel, broadly from September 2015.
Those are guides, not guarantees. Manufacturers certified engines at different times, so two cars registered in the same month can sit on opposite sides of the line. The recorded standard beats guessing from the year, every time.
Emissions on the MOT
The MOT emissions test is a different thing from the Euro standard. The standard is what the car was built to meet. The test measures what it actually emits on the day.
A car can hold a Euro 6 rating and still fail its MOT emissions test if the DPF is blocked or the engine is worn. Repeat emissions advisories in the MOT history are worth reading closely, because DPF and catalytic converter work is expensive.
Why check before buying?
The emissions record helps you compare similar cars, anticipate tax questions and confirm that the advert matches the registered vehicle. Compare the returned fuel type, engine size, year and CO2 figure with the V5C and seller's description.
This free check uses existing DVLA vehicle information where available and does not trigger a separate paid provider request.
CO2 figures, Euro standards and fuel types come from DVLA and DVSA sourced records. REGUP is an independent vehicle checking service and does not claim to be DVLA, DVSA or GOV.UK. More on the about REGUP page.
Older vehicles sometimes have no Euro standard recorded. Where that happens, the registration date and fuel type give a reliable indication.
What this free result includes
REGUP keeps this page focused on the check the customer searched for, with the number plate input first and the most relevant result surfaced before the wider report journey.
- Number plate lookup and basic vehicle identity where available.
- Car Emissions Check result shown first for this page.
- Tax, MOT or mileage context where it is available from supported sources.
- Clear route to unlock remaining paid checks without re-entering the registration.
What the paid report unlocks
Paid REGUP reports can combine the checks a buyer needs before making a decision, with selected checks shown clearly in the report, PDF and email.
- Finance, stolen, write-off, keeper, valuation and specification checks where selected or included.
- Selected checks summary, key findings and plain-English buyer advice.
- Downloadable PDF and email links after purchase where available.
- Upgrade options for partial or custom reports when admin offers are active.
Want to see the report before buying?Open a sample REGUP vehicle report with selected checks, risk summary and locked or unlocked examples.
View sample reportImportant report note REGUP vehicle reports are data checks from available DVLA, DVSA and provider sources. They are not legal, financial or mechanical advice. Source availability can vary by vehicle and customers should enter the registration carefully before checkout.
Car Emissions Check FAQs
Is the car emissions check free?
Yes. It uses existing free vehicle data and does not require a separate paid emissions API request.
Does the result show real-world emissions?
No. It shows recorded or standardised vehicle data, not a live tailpipe test. Real-world results can differ.
Does CO2 determine ULEZ status?
No. ULEZ commonly depends on Euro standard, vehicle category and fuel type. Use the dedicated ULEZ check and verify with TfL.
Why is the CO2 value unavailable?
Some vehicle records do not include a conclusive CO2 figure. REGUP shows Not available rather than estimating an unsupported number.
Is CO2 the same as the Euro standard?
No. CO2 is a measured output in grams per kilometre and mainly drives road tax. The Euro standard is a certification covering NOx and particulates, and it's what clean air zone charges are usually based on.
Do electric cars have an emissions check?
Yes, and they return zero tailpipe CO2. They're still subject to schemes like the London congestion charge, and from April 2025 they're no longer exempt from road tax.
Check recorded vehicle emissions free
Enter a UK registration to see the available CO2 and fuel information, then use the tax or ULEZ checks if you need those specific decisions.