What is my car's CO2 band?

A car's CO2 band is a banding system used mainly for road tax (VED) purposes, grouping vehicles by how much CO2 they emit per kilometre — the lower the band, the lower the emissions, and generally the lower the tax.

How bands are generally structured:

• Bands are typically labelled alphabetically (A being the lowest emitters, moving up through the alphabet for higher-emitting vehicles), though the exact structure and rates have changed over the years, particularly around the April 2017 tax rule change
• Zero-emission vehicles (fully electric) usually sit in the lowest band, historically with £0 tax, though EV tax treatment has been evolving, so it's worth checking the current rate for your registration year
• Your CO2 band is determined by the official g/km CO2 figure recorded for your exact model and trim at the time of registration

Where to find your band:

Your V5C logbook lists the CO2 emissions figure, and a registration lookup will typically show both the raw g/km figure and which tax band it falls into, since the two are directly linked. If you're comparing two similar cars, it's worth checking the actual banding rather than just the raw CO2 number, since the tax difference between two nearby bands can sometimes be more significant than the emissions gap suggests.