Car Insurance Groups Explained (1 to 50)

Car insurance groups are a rating system that places every new car into one of 50 bands, from group 1 (cheapest to insure) up to group 50 (most expensive). The lower the group, the lower the insurance premium tends to be - which is why the group of a car you're thinking of buying can matter almost as much as the sticker price. This guide explains what the groups are, who decides them, exactly what pushes a car up or down the scale, and how you can use that knowledge to keep your costs down.

A quick word on what groups are not: they are only one ingredient in the price you'll actually be quoted. Your age, address, mileage and no-claims history all feed into the final figure too. We'll cover how it all fits together, and link you to the official sources at the end so you can verify everything yourself.

What is a car insurance group?

Every car sold in the UK is assigned an insurance group between 1 and 50. The system is run by the Group Rating Panel, made up of members from the Association of British Insurers (ABI) and Lloyd's Market Association, and the technical research behind it is carried out by Thatcham Research - an independent automotive risk centre funded by the insurance industry. Thatcham tests and analyses cars, then recommends a group; insurers use that recommendation as a starting point for pricing.

In short, the group is a shorthand for "how much is this car likely to cost an insurer if something goes wrong?" A car that's cheap to repair, hard to steal, low-powered and inexpensive to replace will sit near group 1. A fast, valuable car with pricey parts and a high repair bill will sit near group 50.

Crucially, insurers don't have to follow the recommended group to the letter - it's a guide, not a law. But it's a strong guide, and it explains most of the difference in base price between, say, a city runaround and a performance saloon.

What decides a car's insurance group?

Thatcham looks at a defined set of risk factors when recommending a group. Understanding these helps you see why two cars of similar price can land in very different groups.

You'll notice value and performance pull a car up the scale, while strong security and cheap, quick repairs pull it down. That's why a small, well-protected hatchback with a modest engine is the classic group 1 candidate, and a high-powered executive car is up near group 50.

Why lower groups are cheaper to insure

The logic is straightforward: insurance is a bet on risk and cost. A low-group car is statistically cheaper for the insurer if it's stolen, crashed or written off - smaller repair bills, cheaper parts, lower replacement value and less temptation for thieves. The insurer passes those lower expected costs on to you as a lower base premium. A high-group car carries the opposite risk profile, so the base premium is higher before any of your personal details are even considered.

This is also why insurance group is one of the smartest things to check before you buy a car, not after. Two cars that cost the same to buy can cost very different amounts to run over several years once insurance - and tax and fuel - are added in. Running-cost tools can help you compare the full picture; the calculator below shows what you'd pay in vehicle tax, which sits alongside insurance in your annual budget.

For the other big running costs, try our Car Tax Calculator and Fuel Cost Calculator to estimate tax and fuel before you commit to a car.

The 1-50 system vs the old 1-20 system

You may still see references to a 1-20 grouping. That was the original ABI system, used for many years, where cars were rated from 1 (cheapest) to 20 (most expensive). As cars became more varied and complex, 20 bands no longer captured the spread of risk finely enough, so the industry moved to the broader 1-50 scale that's standard today. The 1-50 system gives insurers more precision - there's a meaningful difference between a group 12 and a group 18 car, for example, that the old 20-band scale would have blurred.

For everyday buyers, the takeaway is simple: the 50-group scale is the one in use now, and the principle is identical - lower number, lower expected insurance cost. Some insurers also add a letter suffix (such as E for "exceeds" or A for "acceptable" security) to flag how a car's security measures affected its rating.

Group is only one factor in your premium

Here's the part people most often get wrong: the insurance group sets a baseline, but your actual quote depends heavily on you and how you'll use the car. The same group 5 car can cost one driver a few hundred pounds a year and another well over a thousand. The biggest personal factors include:

• Your age and experience. Younger and newly qualified drivers pay far more, regardless of group, because they're statistically more likely to claim.
• No-claims discount. Several years of claim-free driving can cut your premium substantially.
• Where you live. Postcodes with higher rates of theft, accidents or claims push prices up.
• Annual mileage. More miles means more exposure to risk, so higher mileage usually means a higher price.
• Where the car is kept. A locked garage or driveway typically costs less to insure than parking on the street.
• Job and use. Some occupations are rated higher, and using the car for business costs more than social-and-commuting use.
• Voluntary excess. Agreeing to pay more towards a claim yourself usually lowers the premium.

So a low group is helpful, but it won't single-handedly make you cheap to insure - and a slightly higher group on the right car can still work out affordable if your other details are favourable.

How to find a car's insurance group

You don't need to guess. There are several easy ways to check before you buy:

• Use the free group checker on Thatcham Research's website, which lists the recommended group for cars.
• Look at a price comparison site or an insurer's site - many show the group when you enter a registration or model.
• Check the manufacturer's brochure or specification sheet; the insurance group is often listed alongside the technical data.
• Ask the dealer directly - they can usually tell you the group for any model and trim.

Remember that the group can vary by trim and engine within the same model range - a basic version may be several groups lower than the top-spec one, so check the exact variant you're considering.

How to lower your premium

Beyond choosing a sensible group, there's plenty you can do to bring the price down:

• Buy a lower-group car. If insurance cost matters, shortlist lowest insurance group cars - typically small hatchbacks and city cars with modest engines and good security. A car insurance group 1 model is the cheapest starting point for new and young drivers.
• Build and protect your no-claims discount. It's one of the most powerful levers; consider protecting it once you've built a few years.
• Increase your voluntary excess - but only to a level you could genuinely afford to pay if you claimed.
• Improve security. An approved alarm or immobiliser, and keeping the car off the street overnight, can reduce the price.
• Pay annually if you can. Paying monthly usually adds interest, making the total cost higher.
• Consider telematics (black box) cover if you're a low-mileage or younger driver - it prices you on how you actually drive.
• Shop around and renew early. Don't auto-renew; comparing quotes a few weeks before renewal often beats the loyalty price.
• Be accurate about mileage and use. Estimate honestly, but don't overstate your annual mileage.

Common mistakes to avoid

• Assuming the group is the only thing that matters. A low group won't rescue a quote if you're a new driver in a high-risk postcode. Always get real quotes for the specific car.
• Forgetting that modifications can push up the group - and the price. Alloy wheels, engine remaps, body kits and performance upgrades can increase repair cost, theft risk and performance, raising what you pay. They must also be declared, or your cover may be invalid.
• Not checking the exact trim and engine. The group can jump several bands between a base model and a higher-spec or more powerful version of the same car.
• Ignoring total running costs. A cheap-to-buy car in a high group, with high tax and poor fuel economy, can cost more overall than a pricier car that's cheap to run.
• Under- or over-declaring details to cut the price. Giving false information ("fronting", understating mileage, wrong address) can void your policy and leave you uninsured when you need it most.

FAQs

What is a car insurance group?

It's a rating from 1 to 50 that reflects how costly a car is likely to be to insure. Group 1 cars are the cheapest to cover and group 50 the most expensive. The rating is recommended by Thatcham Research and the ABI's Group Rating Panel, based on factors like repair cost, value, performance and security.

Is a lower insurance group always cheaper?

A lower group usually means a lower base premium, but your final price also depends on your age, postcode, mileage, no-claims discount and how you use the car. A low-group car driven by a high-risk driver can still be expensive, so always compare actual quotes.

What cars are in insurance group 1?

Typically small, low-powered hatchbacks and city cars with good security and cheap, easy repairs. Exact models change over time, so use the Thatcham group checker or a comparison site to find current group 1 cars before buying.

Do modifications change my insurance group?

Modifications don't change the official group itself, but they can increase your premium because they affect performance, value, repair cost or theft risk. You must always declare modifications to your insurer - failing to do so can invalidate your cover.

What's the difference between the 1-50 and 1-20 groups?

The 1-20 system was the older ABI scale. The industry now uses the more detailed 1-50 scale, which spreads cars across more bands for greater pricing precision. The principle is the same in both: a lower number means lower expected insurance costs.

Sources

• Thatcham Research - Insurance Group Rating
• Association of British Insurers (ABI) - Motor insurance
• MoneyHelper - How to cut the cost of your car insurance

For more on the cost of running a car, see our insurance guides.

This guide is general information, not personal financial advice. For your own circumstances, speak to a qualified adviser.