A CO2 emissions checker is a lookup that reads a vehicle's registration number and returns the carbon dioxide figure held on its official record, measured in grams per kilometre (g/km). The figure comes from the Driver and Vehicle Licensing Agency (DVLA) record, which is built from the vehicle's type approval, and it is shown where one has been recorded. Enter the reg into the free number plate check to see it beside the fuel type, engine capacity and Euro status.
Part of DVLA Vehicle Details. Start with the main guide: Car Spec Check by Registration
Updated October 2026 · Independent information, not legal advice
The CO2 figure matters for more than curiosity. It can decide the tax band on older cars, feeds company car tax, and sits alongside the Euro standard when you ask whether a car can enter a low emission zone. The answers below explain what the number means, where it can be missing or misleading, and how to check a car against the zones that affect you.
What Does A CO2 Emissions Checker Show?
A CO2 emissions checker shows the CO2 emissions figure recorded for a registration, normally in g/km, together with the details that explain it.
- The fuel type, such as petrol, diesel, electric or hybrid.
- The engine capacity in cubic centimetres for combustion engines.
- The year of first registration and the year of manufacture.
- The Euro status where the record carries one.
- Tax status and MOT status, which sit on the same vehicle record.
What the figure is not
It is not a measurement of your own car on the road. It is a laboratory-based type approval value, so real-world output varies with driving style, load, traffic and condition.
Which details a lookup can and cannot give
| Detail | Shown? | Where else to look |
|---|---|---|
| CO2 in g/km | Where recorded | The V5C or manufacturer |
| Euro status | Where recorded | Certificate of conformity, dealer |
| Zone compliance | No, only the inputs | Official zone checker |
| Insurance or finance | No | askMID or a commercial history check |
How Do I Check CO2 Emissions By Reg?
To check CO2 emissions by reg, type the registration number into the lookup and read the emissions line in the result. No logbook, account or payment is needed, because the data is drawn from official DVLA and DVSA records.
- Find the registration on the number plate or the V5C registration certificate.
- Enter it without spaces or with the usual gap, as the lookup accepts either.
- Confirm the make, model and colour match the car in front of you.
- Read the CO2 figure, fuel type and Euro status.
Who can use the check
Anyone can look up a registration, whether they are the keeper, a buyer, a fleet manager or a curious neighbour. The result describes the vehicle, not the person.
Check emissions by reg for a car you are buying
Before you buy, check emissions by reg and compare the result with the advert. A figure that looks wildly different from similar models can point to a wrong model listing or a data gap worth asking about.
Check Vehicle CO2 Emissions On The Official Service
The official DVLA Vehicle Enquiry Service (VES) on GOV.UK also lets you check vehicle CO2 emissions for free. It returns make, colour, fuel, engine capacity, tax and MOT status and, depending on the vehicle, the CO2 figure. If the two sources ever differ, GOV.UK is the final word. Read more about what the service returns in the DVLA Vehicle Enquiry Service explainer.
Check CO2 Emissions By Registration Number: What You Need
To check CO2 emissions by registration number you only need the reg. You do not need the VIN, the keeper's name or the V5C reference.
Details you can use alongside the reg
- The make and model, to confirm the right car came up.
- The date of manufacture against the first registration year.
- The colour, to match the car in front of you.
Why no personal details are asked for
Vehicle technical data is separate from keeper data. The DVLA does not release registered keeper names or addresses through a free check, and a lookup that asks for them is not a normal emissions check.
Check Car CO2 Emissions: Reading The Grams Per Kilometre
When you check car CO2 emissions the figure is a simple count of grams of carbon dioxide per kilometre driven under test conditions.
- A low figure generally means a smaller, lighter or more efficient car.
- A high figure generally means a larger engine, heavier body or older design.
- A zero figure normally means a fully electric vehicle.
Rough ways to read a figure
- A small figure suggests a small petrol, hybrid or efficient diesel.
- Mid-range figures usually fit family hatchbacks and saloons.
- Large figures generally fit big SUVs, sports cars and older heavy models.
Why two similar cars have different figures
Tyres, gearbox, body style and optional equipment all influence the type approval figure. Two cars of the same model can therefore carry different numbers.
Car CO2 Emissions Checker: Why The Number Is Recorded
A car CO2 emissions checker reads a field the DVLA stores because vehicle excise duty has linked tax to CO2 for many years. The DVLA records the value once, normally at first registration, and it rarely changes.
Check My Car Emissions By Reg: Step By Step For Owners
If you want to check my car emissions by reg as an owner, the steps are the same as for any vehicle, but you can also compare the result with your logbook. The V5C shows CO2 for many cars too, which helps you spot a typing error on the record.
Using the logbook to cross-check
The V5C often lists CO2 and fuel type too. If a car's logbook and the lookup disagree, treat that as a prompt to ask questions, not as proof of a fault.
Why Is The CO2 Figure Missing On My Car?
The figure can be blank for good reasons.
- Vehicles first registered before CO2 was recorded often have no figure.
- Some imports and older cars were never type approved in a way that gave one.
- Motorcycles, vans and heavy vehicles can follow different rules.
- Electric vehicles may show zero or be left empty.
Why older cars have no figure
CO2 recording on the vehicle record came in with the CO2-based tax bands, so cars from before then often show nothing. That is a normal gap in the data, not a flag against the car.
What to do about a blank figure
A blank does not mean the car is non-compliant. Check the Euro status, fuel type and date of manufacture instead, and use the official zone checker for the area you drive in.
What Is CO2 And How Does It Differ From Other Pollutants?
CO2 is a greenhouse gas linked to fuel burned, so more fuel generally means more CO2. It is not the same as the nitrogen oxides (NOx) and particulates that low emission zones target. A car can have a modest CO2 figure but still fail a zone standard if it is an older diesel.
Particulates, NOx and why diesels are singled out
Older diesels tend to emit more nitrogen oxides and soot. That is why zone rules lean on the Euro standard, and why a clean-looking CO2 figure on an old diesel is no guarantee of entry.
CO2 versus Euro standard
CO2 is about carbon output, the Euro standard is about regulated pollutants. Zones almost always use the Euro standard, not CO2, to decide who pays.
Emissions For My Car: Where The Data Originates
The emissions for my car on a lookup come from the manufacturer's type approval, submitted to the vehicle approval authority and passed to the DVLA at registration. The DVLA then holds it as part of the vehicle record, which is why a change of keeper does not alter it.
Who sets type approval
Type approval is granted before a model goes on sale. The DVLA holds the outcome on the record, but it does not run the emissions test.
What Emission Class Is My Car?
To find out what emission class is my car, look at the Euro status on the record, then at the year of first registration and fuel type.
- Euro 1 to Euro 3 cover older petrol and diesel cars from the 1990s into the 2000s.
- Euro 4 is generally linked to petrol cars from the mid-2000s.
- Euro 5 is generally linked to diesel cars from around 2011.
- Euro 6 is generally linked to diesel cars from around 2015 and most petrols from later in the 2010s.
Dates are only a guide. The record itself or the manufacturer is the safer source.
Why the label does not always match the year
A car first registered late in a year may be an earlier or later standard than neighbours on the forecourt, because makers phase models in at different times. Check the individual vehicle.
Euro Status Checker: What The Euro Number Means
A Euro status checker reports the European emission standard a vehicle was approved to. Each step, from Euro 1 upwards, tightens limits on pollutants such as NOx and particulates. Higher numbers are cleaner.
Euro 1 to Euro 6 at a glance
| Standard | Typical vehicles | Zone relevance |
|---|---|---|
| Euro 3 and earlier | Cars from the 1990s and early 2000s | Usually fails modern zone standards |
| Euro 4 | Many petrols from the mid-2000s | Often the petrol baseline in zones |
| Euro 5 | Many diesels around 2011 | Often not enough for diesel zones |
| Euro 6 | Diesels from around 2015 onwards | Often the diesel baseline in zones |
Where Euro status comes from
It is recorded on the V5C or the certificate of conformity for many vehicles, and the DVLA record shows it where known. If it is missing, the manufacturer's dealer can usually confirm it from the VIN.
What Euro Is My Car? A Check By Reg
To answer what Euro is my car check questions quickly, enter the reg and read the Euro line. If none appears, work from the date of manufacture and fuel type, then verify with the zone checker for your city.
Is My Car Euro 6?
Whether is my car Euro 6 is true depends on fuel type and age. A diesel registered from late 2015 onwards is generally Euro 6, and many earlier ones are not. Petrol cars have a different timeline.
Is my car Euro 6 compliant for a zone?
Is my car Euro 6 compliant is really a question about the zone's rules. Most zones use Euro 6 for diesels and Euro 4 for petrols as a baseline, but each scheme publishes its own standard, so confirm with the local authority or Transport for London (TfL).
Is my car Euro 6 diesel or a petrol?
Is my car Euro 6 diesel matters because Euro 6 for diesel was the big NOx tightening. A diesel labelled Euro 6 meets the cleaner diesel limit used by most zones, while a petrol is judged on a different standard.
Euro 6 Checker: A Quick Method
A Euro 6 checker is really three checks in one.
- Look up the reg to read fuel type and first registration date.
- Read the Euro line if the record shows one.
- Run the official zone checker to see if the vehicle is compliant in the area you plan to drive.
Is My Car Petrol Or Diesel?
If you are asking is my car petrol or diesel, the lookup answers it directly because fuel type is recorded on the registration. It matters in zones, since a petrol and a diesel of the same age can be treated differently.
Mild hybrids and range extenders
Some cars carry a hybrid badge but run a conventional engine for most of their output. Zones normally look at the engine's standard, so verify with the checker rather than the badge.
Hybrids and plug-in hybrids
Hybrids are usually listed with a petrol or diesel base plus a hybrid label. Their zone status follows the engine's Euro standard and, in some schemes, a separate rule for plug-in models.
Low Emission Zone Check: What It Means
A low emission zone check tests whether a registration meets the entry standard for a zone where polluting vehicles are restricted or charged. Zones are set by local authorities, not the DVLA, and the rules, boundaries, hours and charges change, so use the official checker for the exact zone.
How a vehicle is matched to a zone
Cameras read the number plate, the scheme looks the registration up against vehicle data and the result is compared with the zone standard. That is why a correct, legible reg and an accurate record both matter.
Types of zone in the UK
- The Ultra Low Emission Zone (ULEZ) in London, set by TfL.
- Clean air zones in some English cities, set by local councils.
- Low emission zones in some Scottish cities, set by the local councils.
- Zero emission zone pilots in a few places.
Who runs zone schemes
Transport for London runs the ULEZ. Local councils run clean air zones and Scottish low emission zones. None of these are DVLA services.
Check Clean Air Zone Status By Reg
To check clean air zone status, use the GOV.UK clean air zone vehicle checker. It takes the registration and tells you whether a charge applies in each charging zone in England. Vehicle class matters, because cars, vans, taxis and lorries are treated differently.
London Emission Zone Check
A London emission zone check is done on the Transport for London checker using the reg. It reports whether the vehicle meets the ULEZ standard. Generally, petrol cars need Euro 4 and diesels need Euro 6, but TfL sets the rule and any charge. Exemptions and hours change, so check TfL directly.
What the TfL checker asks for
It asks for the registration and, for some vehicles, a few extra details. Only use the official TfL address, and be cautious of unofficial payment pages.
The Congestion Charge is separate
The Congestion Charge is a different scheme from ULEZ. See the congestion charge zone map for London to see where it applies.
Birmingham ULEZ Check
People often search for a Birmingham ULEZ check, but Birmingham operates a Clean Air Zone, not a ULEZ. The idea is similar: a charging area where vehicles that do not meet the standard may pay. Use the GOV.UK checker with your reg.
Bristol ULEZ Check
A Bristol ULEZ check is similarly a clean air zone check, since Bristol uses that scheme name. The Bristol ULEZ checker the public wants is the GOV.UK vehicle checker for English clean air zones.
Is my car ULEZ compliant in Bristol?
For is my car ULEZ compliant Bristol, enter the reg into the GOV.UK checker, pick Bristol and read the result. Charging classes and exemptions are set locally, so confirm with Bristol City Council.
Same name, different rules
Even within clean air zones, charging classes differ between cities, and a vehicle may be free in one and charged in another.
Birmingham ULEZ Checker And Bristol ULEZ Checker Questions
If you need a Birmingham ULEZ checker or a Bristol ULEZ checker, the same official GOV.UK tool covers both cities because they sit under the English clean air zone programme.
ULEZ Check Scotland And Glasgow
Scotland uses Low Emission Zones, set under Scottish rules, in cities including Glasgow. A ULEZ check Scotland is therefore really a Low Emission Zone check.
Why Scottish zones differ
Scottish schemes are enforced under separate legislation and generally ban non-compliant vehicles from entering rather than simply charging.
Glasgow low emission zone check
For a Glasgow low emission zone check use the official Scottish LEZ checker and the registration. Enforcement is by number plate recognition cameras, and penalties are set by the local authority.
ULEZ check Glasgow and ULEZ checker Glasgow
A ULEZ check Glasgow and a ULEZ checker Glasgow both lead to the same Scottish checker. Non-compliant vehicles may be refused entry or fined.
Check Car Emissions By Registration For Company Car Tax
Company car tax, a benefit-in-kind charge assessed by HMRC, depends on the car's list price, fuel type and CO2. Employers report it. Check the CO2 and fuel with a lookup, then use the company car tax calculator for how the factors interact, and HMRC for the current bands.
Why the figure matters to employers
A higher figure usually pushes up the benefit-in-kind charge, so fleets often compare candidate cars by CO2 first.
How CO2 Affects Vehicle Excise Duty
Vehicle excise duty (VED) was linked to CO2 for cars registered between March 2001 and March 2017, where the tax band follows the CO2 figure. Later cars follow a different structure with a first-year rate tied to CO2. Rates change annually, so look at the vehicle excise duty explainer and check GOV.UK for the current amount.
Older cars on band-based tax
If a car sits in the older banded system, a wrong CO2 entry could mean the wrong tax band. Compare the figure with the V5C, and read the vehicle tax status check if the amount due looks off.
Cars with a zero CO2 figure
A zero-emission car is not always zero tax. Policy has changed over time, so confirm on GOV.UK.
CO2 Emissions And MPG: How They Relate
Lower CO2 usually matches higher fuel economy for the same fuel. The relationship is direct because burning a litre of fuel releases a set amount of CO2. See MPG for vehicles for how fuel economy figures appear.
Fuel economy versus tailpipe CO2
A thirsty car costs more to run and emits more CO2. The lookup gives only the CO2 side, so use the official fuel consumption figure from the maker for running costs.
Motorbikes, Vans And Classic Cars
- Motorbikes may have CO2 recorded, but zone rules often differ.
- Vans can be judged on a separate standard in zones.
- Classics built before the Euro standards have no CO2 figure and may be exempt from some zones; check the local scheme.
Classic cars and exemptions
A car built long before emission standards will not carry a Euro number. Check classic car tax rules and the local zone's exemptions separately.
Northern Ireland And Imports
Registration and tax in Northern Ireland sit with the DVLA, while testing is run by the DVA, so the CO2 field is still on the DVLA record. Imported vehicles can have gaps because they were approved abroad. The Driver and Vehicle Agency role is covered separately.
Electric vehicles and zones
Fully electric vehicles are usually the easiest to clear in zones, but exemptions are set by each scheme and can change, so confirm each time.
Common Mistakes With Emissions Checks
A car emissions checker that works from a registration only reads what the record holds: it does not measure the exhaust of the car in front of you. The MOT history record can show emissions test results, and the driving licence has no bearing on a vehicle's CO2 figure because licence and vehicle records are held separately.
- Confusing CO2 with Euro status.
- Assuming a clean zone applies everywhere.
- Trusting an advert over the record.
- Forgetting that zone rules differ by vehicle class.
- Using unofficial websites to pay zone charges.
- Treating an old advert's emissions line as the current record.
- Assuming a newer plate always means a cleaner standard.
- Paying a charge for the wrong vehicle by mistyping the reg.
Where the official sources are
- GOV.UK for the Vehicle Enquiry Service and the clean air zone checker.
- Transport for London for the ULEZ.
- The local council or Transport Scotland for Scottish zones.
What To Do If The Record Looks Wrong
If the CO2 figure, fuel type or Euro status looks wrong, check the V5C. If the V5C disagrees with the car, contact the DVLA through GOV.UK to correct it. If the V5C is right but the lookup differs, the manufacturer's dealer can confirm the specification from the VIN.
Quick Checklist Before You Drive Into A Zone
- Enter the reg into the zone's official checker.
- Confirm vehicle class and fuel type.
- Check the zone's operating hours.
- Note how and when any charge must be paid.
If you get a penalty notice
Read the notice, check the reg and date, and follow the appeal route on it. The fine for driving without tax is a different matter, so do not confuse the two.
Frequently Asked Questions
How do I check CO2 emissions by registration number?
Enter the registration into a free vehicle lookup or the DVLA Vehicle Enquiry Service on GOV.UK and read the CO2 line, shown in grams per kilometre where one is recorded. You do not need the VIN or the V5C. If the figure is blank, the vehicle may predate CO2 recording or have been imported, so check the Euro status and fuel type instead.
What does a CO2 figure of zero mean?
Usually that the vehicle is fully electric and produces no tailpipe CO2 under test conditions. It does not necessarily mean zero vehicle tax, because tax policy for zero-emission vehicles has changed over time. Check the current position on GOV.UK before assuming a car is exempt from vehicle excise duty or from zone charges.
Is my car ULEZ compliant?
It depends on the fuel type and Euro standard. As a general guide, petrol cars need to meet Euro 4 and diesel cars Euro 6, but Transport for London sets the rule and can change it. Enter the registration into the official TfL checker for a definite answer, and confirm any charge before you drive in the zone.
Is there a Birmingham ULEZ?
Birmingham has a Clean Air Zone, not a ULEZ, although many people search for a Birmingham ULEZ check. The idea is similar: a charging area for vehicles that do not meet the standard. Use the GOV.UK clean air zone vehicle checker with the reg to see whether your vehicle would be charged.
Can I do a Bristol ULEZ check?
Bristol runs a Clean Air Zone, so a Bristol ULEZ check is really a clean air zone check. Use the GOV.UK vehicle checker for English clean air zones, select Bristol and enter the registration. Charging classes and exemptions are set locally, so Bristol City Council has the final word.
Does Scotland have ULEZ?
Scotland has Low Emission Zones in several cities, including Glasgow, rather than a ULEZ. A ULEZ check Scotland search should therefore lead to the official Scottish Low Emission Zone checker. Enforcement is usually by number plate recognition cameras, and penalties are set by the local authority, so confirm the details before you travel.
How do I know if my car is Euro 6?
Check the Euro status on the vehicle record, then compare it with the date of first registration and fuel type. Diesel cars registered from around late 2015 are generally Euro 6, but the dates are only a guide. The V5C, the certificate of conformity or the manufacturer's dealer can confirm it from the VIN.
Is my car petrol or diesel?
The fuel type is recorded against the registration, so a lookup shows it immediately. You can also check the V5C, which lists fuel type, or look at the fuel filler cap and engine bay labels. Fuel type matters for zones, because a petrol and a diesel of the same age may be treated differently.
Why is the CO2 emissions figure missing?
Older vehicles, some imports and certain motorcycles, vans or heavy vehicles may have no CO2 figure recorded. A blank is not a sign that the car is illegal or non-compliant. Use the Euro status, fuel type and date of manufacture instead, and run the official checker for the zone you need to enter.
Does CO2 decide my road tax?
For cars registered between March 2001 and March 2017, the vehicle tax band generally follows the CO2 figure. Newer cars have a first-year rate linked to CO2 and then a standard rate. Rates change, so check the current position on GOV.UK rather than relying on older charts or adverts.
Are CO2 figures the same as real-world emissions?
No. The figure is a laboratory type approval value, so real-world output varies with driving style, load, traffic and vehicle condition. It is useful for comparing models and for tax rules, but it will not match what a particular car emits on your commute.
Can I check emissions for any vehicle?
Yes, for any Great Britain registered vehicle you can look up the registration. You see what the record holds, which may include CO2, fuel type, engine capacity and Euro status. Northern Ireland vehicle registration records also sit with the DVLA, but MOT testing there is run by the DVA.
How do I check vehicle emissions by reg?
Enter the registration into the free lookup to check vehicle emissions by reg. If the DVLA record holds a CO2 figure and Euro status, they appear alongside fuel type and engine size. Some older or imported vehicles have no figure recorded, in which case the official GOV.UK vehicle enquiry service is the place to confirm what is held.
Can I see the CO2 emissions of my car by registration?
Yes, where a figure is recorded. To check my car CO2 emissions by reg, enter the number plate and read the CO2 and fuel entries. The figure is a type approval value, so it is a guide for comparison and tax, not a measurement of what your own car emits on the road.
Official Sources
Rules, fees and deadlines change. Confirm anything that affects your money or legal position with the official service.