How do I check my car's CO2 emissions?

Question

Accepted Answer

You can check a car's official CO2 emissions figure using its registration number, without needing to dig through paperwork or manufacturer brochures.

Where the figure comes from:

CO2 emissions (measured in g/km) are recorded on the vehicle's official DVLA record at the point of registration, based on manufacturer testing
The same figure is listed on the V5C logbook
A registration lookup will typically show CO2 emissions alongside related details like fuel type, engine size, and tax band, since they all feed into how the vehicle is taxed

A note on testing standards:

The testing standard used to measure CO2 has changed over time — older vehicles were tested under NEDC, while newer ones use the more realistic WLTP standard — so directly comparing the raw CO2 figure between an older and a much newer car isn't always a like-for-like comparison, even for similar-sized engines. If you're cross-shopping cars from noticeably different registration years, it's worth keeping the testing standard in mind rather than assuming the numbers are directly comparable.