Car Insurance Groups Explained: Bands, Costs & Letters

Car insurance groups UK explained in plain terms: every car sold here gets slotted into a band from 1 to 50, and that band is one of the first things an insurer checks before it even looks at you as a driver. Group 1 cars are the cheapest to cover, group 50 cars are the priciest, and where your car sits can make a real difference to what you're quoted. This guide covers how the groups are worked out, who decides them, what's changing with a newer rating system, and what else actually shapes the number you pay.

What is a car insurance group?

An insurance group is a risk rating, not a value rating. It reflects how much a car is likely to cost an insurer: its value, the price and availability of parts, repair times, performance, safety and security features, and how likely it is to be stolen. The rating is set independently of price, so a fairly cheap car with awkward, expensive-to-source panels can end up higher than a pricier model that's simple and cheap to fix.

The system itself carries a lot of detail behind it. Cars and light commercial vehicles featured in the Vehicle Risk dataset are given a Group Rating score, which is used by insurers to help quantify the risk associated with that vehicle, based on data that manufacturers feed directly into Thatcham Research's database. Over 125 data points are reviewed as part of the process, including parts pricing using a standard list of the most commonly accident-damaged panels, and the fitment and performance of autonomous emergency braking systems.

Who actually sets the group, and how

The group isn't picked by the manufacturer or by any single insurer. It comes from a joint industry process. Thatcham Research does the technical work, and a panel made up of insurer representatives from the Association of British Insurers reviews and confirms the rating each model gets. Scores range between 1 and 50 for cars, and 21 to 50 for light commercial vehicles, indicating the level of insurance risk associated with the vehicle. New models and significant updates are reviewed regularly rather than left to sit unchanged for years.

What the panel actually looks at

Beyond the headline number, the assessment covers a wide spread of practical detail:

• Repair strategy, cost and time needed to return the car to its pre-accident condition
• The price and availability of commonly damaged parts such as bumpers, panels and lights
• Vehicle performance, including acceleration and top speed
• Security and anti-theft equipment, including alarms and immobilisers
• Safety technology fitted as standard, such as automatic emergency braking
• New car value and the cost of a total loss replacement

The letter after the group number

If you've seen a group written as something like 15E or 10A, that letter is a security suffix. It shows how the car's security compares with what's expected for a vehicle of that type, and it can nudge the group up or down. A car that exceeds the expected security standard tends to be marked down a notch, while one that falls short of it can be pushed up, even though the base group number stays the same on paper.

The shift towards Vehicle Risk Rating

The 1-50 system has been the industry standard for decades, but it isn't standing still. Thatcham Research launched the Vehicle Risk Rating system on 24 September 2024, followed by a dual-rating period of around 18 months during which both the new VRR and the existing Group Rating system apply. The idea is a finer-grained score that reflects modern vehicle tech more accurately. Each assessment, covering Performance, Damageability, Repairability, Safety and Security, is scored from 1, indicating low risk, to 99, indicating high risk.

In practice this means two systems currently exist side by side. Cars that were already on the road before the changeover keep their familiar 1-50 group. Newer model ranges are being assessed under the new five-part VRR framework, which insurers are gradually working into their pricing alongside the existing groups. If you're comparing a well-established model against a brand-new one, don't be surprised if you see the two scales quoted differently.

Group isn't the whole story

A low group is a good starting point, not a guaranteed cheap premium. The group sets a baseline, but insurers layer plenty of personal factors on top before they land on a final price:

• Your age and how long you've held a full licence
• Your postcode, and local claims and theft data for that area
• Your claims history and any convictions
• How many years' no-claims discount you've built up
• Annual mileage and how the car is used, such as commuting or business use
• Where the car is kept overnight, for example on a drive versus on the street
• The level of cover chosen and the voluntary excess set

Two drivers insuring an identical car in the same group can end up with very different quotes once these factors are weighed in. That's why it pays to shop around on a comparison site rather than assume the group alone tells you what you'll pay.

How to check a car's insurance group before you buy

If you're weighing up a used car, the manufacturer's original spec sheet will usually list the group, and most comparison sites let you search by make and model too. It's worth checking this alongside the basics before you commit to anything. Entering the registration into our reg lookup tool gives you the car's MOT history, current tax status and a free indicative valuation in one go, which is a sensible first step before you start pricing up cover. Remember that a valuation like this is a market guide only, not a fixed price, since actual figures move with condition, mileage and demand.

If you're weighing up several cars before deciding which to buy, our related guides cover other angles worth thinking about, from running costs to what to check before you hand over any money.

Buying with finance

If you're planning to fund the purchase rather than pay outright, it's worth factoring the insurance group into your budget alongside the monthly repayment, since a high-group car can add a noticeable amount to your total running cost. If that's the route you're considering, you can find out more about car finance options, always subject to status and affordability, and never a guaranteed rate or approval.

Practical ways to keep a group-based premium down

A handful of sensible choices can make a genuine difference:

• Compare trims within the same model; the base engine and the sportier version of the same car can sit several groups apart
• Fit or keep any Thatcham-approved security devices, which can improve the security suffix
• Consider a higher voluntary excess if you can comfortably afford it in the event of a claim
• Ask about telematics or black-box policies, which some insurers use to reward lower-risk driving regardless of group
• Keep your no-claims discount protected where you can, since it's one of the few factors entirely within your control

Final thoughts

Understanding car insurance groups won't hand you a firm quote, but it will help you understand why one car costs noticeably more to cover than another that looks similar on paper. Check the group early, alongside the car's history and a realistic valuation, and you'll go into any purchase with a clearer picture of the full cost, not just the price on the windscreen.

Insurance group ratings are reviewed and can be updated by Thatcham Research over a car's life, and the industry is currently running the older 1-50 system alongside the newer Vehicle Risk Rating for different model ranges, so always check the current rating for your specific model and trim via Thatcham's own tools rather than relying on an old printout. Premiums themselves vary between insurers and change over time, so use a comparison site for an up-to-date quote rather than a historical figure.