Every car sold in the UK sits somewhere on a 1 to 50 scale that directly shapes how much you'll pay to insure it, yet most drivers only ever see the number without knowing who sets it, what actually goes into it, or how to use it properly before buying.
Key Takeaways:
- Groups run from 1 to 50, with group 1 the cheapest to insure and group 50 the most expensive.
- The Group Rating Panel sets every rating, combining engineering data from Thatcham Research with claims data from the Association of British Insurers.
- Seven main factors decide a car's group, led by repair cost after a standard low-speed impact test.
- A letter often follows the number (such as 15E or 10A), reflecting the car's specific security compared to what's expected for its type.
- A new Vehicle Risk Rating system is replacing the old scale for new models launched from August 2024 onward, running 1 to 99 instead of 1 to 50.
What Are Car Insurance Groups?
A car insurance group is a rating from 1 to 50 given to every car sold in the UK, reflecting how much it's likely to cost an insurer in repairs, parts and claims. Group 1 is the cheapest to insure, group 50 the most expensive, and the number sits alongside your own personal factors, age, location, driving history, as one of the biggest single influences on your final premium. Insurers use the group as a genuine starting point when pricing a policy, then adjust from there based on everything specific to you as a driver.
Who Sets UK Car Insurance Groups?
The Group Rating Panel sets every UK insurance group, a joint body made up of members from the Association of British Insurers and Thatcham Research, the motor industry's own research centre. Thatcham does the genuine engineering work, running low-speed crash tests, dismantling cars to assess repairability, timing how long a bodyshop takes to fit replacement parts, and pricing those parts directly. The ABI side brings claims data from across the industry instead. Together the panel produces a single number that insurers use as their starting point when pricing a policy, meeting monthly to rate new models as they reach the market.
How Does the 1 to 50 Scale Work?
Until 2009, the system only ran from 1 to 20, expanded to 50 specifically to band similar cars more precisely since a scale of just 20 groups was lumping together cars with genuinely different risk profiles. Most mainstream cars cluster somewhere between group 10 and 30, with the very cheapest city cars sitting in groups 1 to 5 and genuine performance cars often landing above 40.
What Factors Determine a Car's Insurance Group?
Seven main inputs feed into the panel's final rating for any given car.
- Repair cost, the single biggest factor. Thatcham runs a 15 km/h front and rear impact test, close to a typical car park bump, then measures the full cost of returning the car to its original condition.
- Parts cost and availability since expensive or hard to source parts push the group up regardless of how minor the damage.
- Repair time since a car that takes longer to fix costs an insurer more in labour and any courtesy car provided while it's off the road.
- Performance, including engine power and acceleration since faster cars statistically see more claims.
- Safety technology, where features like autonomous emergency braking, lane assist and a strong Euro NCAP rating can pull a car's group down since they measurably reduce claims frequency.
- Security, where a Thatcham approved alarm, immobiliser or locking system lowers the group, while poor key security, including known relay attack vulnerabilities, pushes it up.
- Bumper alignment, checked against the standard European bumper height since good alignment means less damage in low-speed impacts and correspondingly lower repair bills.
Insurance Group Letters
You may sometimes see a letter attached to your car's insurance group number, such as 1E or 10D. These indicate security standards.
- E (Exceeds): The car exceeds security standards for its group, so the rating has been lowered.
- A (Acceptable): The car meets minimum security requirements.
- D (Doesn't meet): The car fails to meet security requirements for its class, pushing it into a higher group.
- U (Unacceptable): Security features are significantly below standard. Insurers may require an upgrade.
- G (Import): The vehicle is an imported model.
One further letter worth knowing, P (Provisional), appears when a car's data was incomplete at the time it launched, common for brand new releases still being fully assessed. Worth checking this letter alongside the number itself, since two cars with the same headline group figure can still differ meaningfully in how they were actually assessed.
Group Breakdown
- Groups 1 to 10: Small city cars and hatchbacks, such as the Citroen C1, Fiat Panda and Volkswagen Polo. Ideal for new drivers since they're the cheapest to cover.
- Groups 11 to 20: Standard family hatchbacks and compact SUVs, such as the Ford Focus, Nissan Qashqai and Mini Hatchback.
- Groups 21 to 30: Larger family cars, higher spec trims and slightly more powerful engines, such as the BMW 1 Series, Audi Q3 and Ford Kuga.
- Groups 31 to 40: Premium models and performance oriented vehicles, such as the Audi TT and Volvo XC90.
- Groups 41 to 50: High performance sports cars and ultra luxury vehicles, such as the Ford Mustang and Porsche Cayman.
Real premiums follow this pattern closely too. Based on comprehensive policy data, average annual premiums rise fairly steadily across the bands, from around £420 for groups 1 to 10 up to roughly £800 for groups 41 to 50.
What Are the Cheapest Car Insurance Groups?
Groups 1 to 10 hold the cheapest cars to insure, and it's worth understanding why rather than just knowing the number. Cars in this band typically share a small engine under 1.2 litres, a modest top speed, cheap and widely available parts, and a low original value, all factors that keep an insurer's worst-case repair bill genuinely low. Engine size matters more than most buyers expect too. A larger engine in an otherwise similar small car can push it up several groups even before performance or trim level are considered, exactly why two visually near-identical city cars can still land in different bands depending purely on which engine option was fitted.
What Is the New Vehicle Risk Rating System?
Since August 2024, new car model ranges launched in the UK no longer use the traditional 1 to 50 scale. They're rated instead under a new Vehicle Risk Rating, running from 1 to 99 across five separate risk categories rather than one combined score, though this change hasn't applied retrospectively. Any car already on sale before that date, along with new variants of an existing model range, still carries its original 1 to 50 group. Over time, as more genuinely new models reach the market, the two systems will run alongside each other before the older scale is gradually phased out entirely. Anyone buying a used car registered before August 2024 will still see the familiar 1 to 50 figure for the foreseeable future.
How Can You Check a Car's Insurance Group?
Free checker tools, including one offered by MoneySuperMarket, let you look up any car's current group using its registration number or make and model. Your existing insurer can also confirm the exact group on request if you're checking a car you're already insuring. Checking this before buying, rather than after, avoids discovering an unexpectedly high premium once you've already committed to a specific car.
Does a Car's Insurance Group Ever Change?
A car's initial rating tends to stay stable for most of its production run, though not fixed forever. The panel can revise a rating if genuinely new data emerges, such as parts prices shifting significantly or real claims data showing repair costs running higher or lower than first assessed, more often around a mid-life facelift when safety or security equipment genuinely changes than during the middle of an unchanged production run. An older example of a long-running model can therefore sit in a slightly different group to a more recently updated version of the same car.
Is Insurance Group the Same as Write-Off Category?
No. The two are easy to confuse though. Insurance group reflects how much an undamaged car is expected to cost an insurer in future claims. Write-off category, such as Cat N or Cat S, only applies after a car has already been declared a total loss following an accident, with nothing to do with its original 1 to 50 rating. A car can carry a genuinely low insurance group and still have a write-off category in its history from a previous accident. Checking both separately matters when buying used.
How Much Can Choosing the Right Group Actually Save?
Meaningfully. Choosing a car in groups 1 to 5 instead of 15 to 20 can cut a premium by £500 to £1,000 a year for the same driver, particularly for young or new drivers already facing a higher starting quote. For the full detail on every other factor shaping your premium beyond the car itself, see our guide on getting cheap car insurance.
Why Do Electric Cars Often Sit in Higher Groups?
Battery repair costs are the main reason. Research from Thatcham itself has found electric vehicles cost around 25 percent more to repair than equivalent petrol or diesel models, with repair times running roughly 14 percent longer too. A damaged battery pack can be expensive enough to write a car off entirely for damage that would be a straightforward repair on a combustion engine, pushing many electric models higher than their petrol equivalents despite often having strong safety ratings and simpler mechanical layouts otherwise.
Do Classic Cars Have Their Own Insurance Group?
No. Classic and older collectible cars generally fall outside the standard 1 to 50 system entirely, assessed individually instead based on age, value, usage and any specialist repair requirements rather than the mainstream engineering tests applied to current models. A dedicated classic car policy usually makes more sense than standard cover once a vehicle reaches this category.
How Can I Save Money on My Car Insurance Based on Insurance Group?
Two trims of the same car can sit several bands apart. Confirming the specific engine and trim you're actually considering matters more than the model name on its own. Keeping a car unmodified matters too. Even cosmetic changes like alloy wheels or a different exhaust can push a car into a higher group once declared to your insurer, regardless of how the car actually drives. Choosing a car with strong factory-fitted security, rather than adding it aftermarket later, also helps. A car already meeting or exceeding its group's security expectation avoids the D rating that pushes cheaper cars up unnecessarily.
Beyond the group itself, a wide range of other factors shape your final premium too, covered fully in our guide on getting cheap car insurance.
Frequently Asked Questions
What is the cheapest car insurance group? Group 1 is the cheapest band available, typically occupied by small city cars with modest engines and strong security ratings.
Does a car's insurance group affect road tax too? No. Insurance groups and car tax bands are set by entirely separate systems, covered fully in our guide on car tax explained.
Can two identical looking cars have different insurance groups? Yes, particularly if they're different trims or engine sizes since performance and specification both feed directly into the final rating even within the same model range.
Is a lower insurance group always better? For minimising your premium specifically, yes, though it shouldn't be the only factor in choosing a car. Practicality, reliability and running costs all matter too, covered in our guide on cheapest cars to run in the UK.
Do electric cars follow the same insurance group system? Yes, electric cars are rated under the same 1 to 50 scale, or the newer Vehicle Risk Rating if launched from August 2024 onward, though they often land in a higher group than expected, covered fully above.
Conclusion
Insurance group is one of the few factors shaping your premium that you can genuinely choose before you ever apply for cover. Knowing who sets it, what actually goes into the number, and what the letters alongside it mean turns a single confusing figure into something you can compare properly across different cars.
Checking the exact group for the specific trim and engine you're considering, rather than assuming based on the model name alone, remains the single most useful habit from everything covered here since it's the one step that puts you in control before you've committed to a car rather than discovering the real cost afterward.
Every car sold through Car Planet has its insurance group clearly listed. You can check the real cost of cover before you commit to a specific car.
