What are UK insurance groups?

Every car sold in the UK is assigned an insurance group from 1 to 50 by the Group Rating Panel (made up of the ABI and Thatcham Research). Group 1 is the cheapest to insure and group 50 is the most expensive. The group is based on damage and parts costs, repair times, performance, security, and new car value.

What factors affect insurance group?

The main factors are: vehicle value (higher value = higher group), engine size and power (more power = higher group), repair costs and parts availability, body type, safety features, and Thatcham-approved security devices. Cars with expensive parts or that are commonly stolen tend to be in higher groups.

Does the insurance group determine my premium?

The insurance group is just one factor. Your actual premium also depends on your age, driving experience, claims history, no-claims discount, where you live, annual mileage, and how you use the car. Two people with the same car can pay very different premiums.

How can I lower my insurance group?

You cannot change a car's insurance group, but you can choose a car in a lower group. Look for smaller engines, lower power outputs, cheaper parts availability, and good security ratings. Adding Thatcham-approved alarms and immobilisers can sometimes help.

What is Thatcham Research?

Thatcham Research is the UK motor insurers' automotive research centre. They test vehicle security, crash repair costs, and safety features. Their ratings directly influence insurance groups. Thatcham Category 1 (alarm + immobiliser) is the highest security rating.

CarCalcs

Insurance Group Calculator — Estimate Your Car's Group

Estimate your car's insurance group (1-50) based on engine size, power, value, and security features.

Engine Size

Power

Vehicle Value

Vehicle Age

Body Type

Security Level

How We Calculate This

How Insurance Groups Are Estimated

This calculator uses a simplified model based on the key factors that the Group Rating Panel considers:

Engine size: Larger engines generally mean higher groups
Power (BHP): Higher performance increases the group rating
Vehicle value: More expensive cars cost more to repair and replace
Body type: Sports cars and convertibles are rated higher than hatchbacks
Security: Thatcham-approved security can lower the group
Vehicle age: Older vehicles tend to have lower values, reducing the group slightly

The actual group assignment by the ABI/Thatcham uses more detailed data including crash repair costs, parts prices, and theft statistics.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Actual figures may vary based on driving conditions, vehicle specifications, and other factors.