Modified car insurance

Cover for your customised car

Cover that suits your upgrades

Get a policy designed for mods, from alloys to engine tweaks

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What is modified car insurance?

Modified car insurance covers cars that have been changed from the manufacturer’s standard specification.

Because modified cars can be more attractive to thieves and more expensive to repair, insurance can cost more, especially if performance has been increased.

But there are ways you can look to save on modified car insurance. For example, by parking off-street or increasing your excess.

Here's how to insure a modified car and compare quotes to find cover that suits your needs and budget.

What counts as a car modification?

A modification is any change you make to your car that alters it from the manufacturer’s standard settings.

Modifications tend to fall into two categories: performance or cosmetic.

Performance modifications

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    Altering the suspension

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    Changing the wheels

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    Increasing horsepower

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    Turbo upgrades

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    Re-engineering your engine

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    Chip tuning and ECU remaps

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    Intake and exhaust upgrades

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    Handling modifications

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    Lowering the suspension

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    Fuel upgrades

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    Transmission modifications.

Cosmetic modifications

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    Go-faster stripes

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    Body kit amendments

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    Sunroof installation

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    Tinted windows

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    Specialised paintwork

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    After-market speaker systems.

Alloy wheels

Changing the exhaust system

Tinted windows

Suspension changes

Adding a tow bar

ECU remapping

Other modifications you may need to declare

Engine

Changes that increase performance can raise your car’s top speed and may increase your premium.

Bodywork

Changes can increase the car's value as well as affect aerodynamics and safety in a crash. These modifications will need to be declared as soon as they are installed.

Spoilers

These can change handling and may be viewed by insurers as a performance-related modification. If you do fit a new spoiler, ensure it doesn’t block the view from the rear window and is fitted securely by a qualified mechanic.

Parking sensors

Designed to reduce the risk of low-speed bumps, and may be seen as a safety feature by some insurers. This type of modification could mean you’re seen as a safety-first driver, which may reduce your premiums.

Stickers

Even decals could be classed as a modification. For example, the BBC reported a case where a driver was warned that undeclared stickers could affect cover.

How much does modified car insurance cost?

Modified car insurance typically costs

£6333
a year with comprehensive cover

Drivers could save around £41 by avoiding modifications3. That said, not all modifications will increase your premium.

For example, fitting an immobiliser helps make your car more secure and could bring your premium down.

But it’s not just modifications that affect how much you pay. Insurers also consider:

  • Your age

  • Where you live

  • Your job

  • Your driving history, including any no-claims discounts, driving offences or previous claims.

3 Based on 51% of customers who compared quotes for this type of policy in June 2026.

Why does it cost more to insure a modified car?

The cost of your insurance premium is based on the probability of you making a claim. So, when it comes to modifications, insurance providers will consider the following factors:

Increased value

If modifications increase the value of your car, any claims you make could be higher as it may be more expensive to repair or replace parts, or replace the car following an accident.

Increased performance

If you’ve made your car faster, that could increase the risk of you being involved in a speed-related accident.

Theft risk

Your car may be at greater risk of theft and vandalism, especially if you’ve had expensive tech installed or you’ve modified its performance.

Vehicle integrity

Insurance providers could assume that any modifications that alter the manufacturer’s standard settings can’t be guaranteed and may affect the car’s integrity.

Young drivers

17 to 24-year-olds are statistically more likely to claim on their insurance, so any modifications could raise their premium even more.

What does modified car insurance cover?

Insurance for modified cars will cover you for the same risks as any other car insurance policy. You’ll have three levels of cover to choose from:

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Third-party only

Third-party only – the minimum level of cover you need to legally drive in the UK. It covers injuries to third parties and damage to their property. It won’t cover your own car.

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Third-party, fire and theft

Third-party, fire and theft – includes third-party cover plus cover against fire, damage or theft of your own vehicle.

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Comprehensive

Comprehensive – the highest level of cover. It includes third-party, fire and theft cover as well as damage to your own car, even if you’re at fault.

Optional extras for modified cars

You can also take out the usual optional extras with your modified car insurance.

Optional extras could increase the cost of your premium, so think carefully about adding additional cover that you may not need.

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What modifications could help lower my car insurance?

Here are some modifications that could lower your premium:

Parking sensors

These can lower the risk of minor bumps.

Security measures

By fitting an immobiliser or tracking device, potential thieves could be discouraged.

Tow bar

If you use your car for towing a caravan, horse box or trailer, you’re likely to drive more slowly and carefully, so a tow bar could lower your premium. Then again, insurance providers might also consider towing to be an added risk. So, it’s worth checking with your provider before you get one fitted.

Sway bars

Also known as anti-roll or stabiliser bars, these can help you distribute the car’s weight evenly and reduce body roll when turning or swerving.

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Modifications for disabled drivers

Some cars can also be modified to make them easier to use for drivers with disabilities. For example:

  • Wheelchair ramps and lifts

  • Altered foot pedals

  • Hand controls

  • Steering aids.

In Great Britain, the Equality Act 2010 protects disabled people from unfair discrimination when buying insurance. In Northern Ireland, different equality legislation applies, but the general principle is the same.

Insurers shouldn’t treat you differently just because you’re disabled. However, if some modifications are expensive to repair or hard to replace, premiums may be higher to reflect these.

Do I have to tell my insurance provider about modifications?

Yes, by law you must tell your insurance provider about any modifications to your car, even if you didn’t make the changes yourself.

If you don’t disclose modifications, it could invalidate your car insurance. This means you could be driving without insurance, which is illegal.

When you speak to your insurance provider, let them know:

  • About all modifications, even minor ones

  • Details about the modifications including cost and who fitted them (keep all receipts and records of the modifications)

  • About any modifications you wish to make.

While you should be able to insure a modified car quite easily, you need to make sure that your modifications are legal. If any of them break the law, you won’t be able to get cover at all.

Some common examples of illegal modifications include:

  • Neon lights fitted under the car

  • Overly tinted windows (they must let in at least 70%-75% of light)

  • Excessively loud exhausts (they mustn’t exceed 74 decibels).

What to do when you modify your car

Telling your insurance provider at the right time helps keep your cover valid. Here’s what to do before you modify your car, straight after and when you renew your policy.

When

What to do

Before you modify

Check the modification is legal. Tell your provider what you plan to change and ask how it might impact your cover and premium.

Straight after modifying

Tell your provider as soon as the work is done. Give details of what’s changed, how much it cost and who fitted it. Keep your receipts.

When you renew your car insurance

Declare every modification when you compare quotes, including ones your current provider already knows about. This will ensure you get accurate quotes and are properly covered.

Amy Rootham

What our expert says...

“If you’re buying a second-hand car, ask the seller for a full list of its modifications and any receipts for the work. Then, tell your insurer about them as soon as you buy it.

“Planning a performance mod? Let your provider know and ask how it could affect your cover and premium before committing.”

How can I save on modified car insurance?

It might not always be easy to get cheap modified car insurance, but there are ways to lower your premium.

For example, you might get cheaper modified car insurance by:

  • Park in a safe place overnight – those who park on their driveway could save around £358 a year on car insurance compared to those who park on the street3

  • Having a voluntary excess – for example, people typically save £216 by adding a voluntary excess of £100 on top of their compulsory one, compared with those who have no voluntary excess4.

  • Comparing comprehensive cover – Drivers typically save £325 by choosing a comprehensive policy compared with third party, fire and theft, or £649 compared to third party only, even though it provides the highest level of cover. It's always worth checking all your options before you buy4.

If you want to know how any particular modification will affect your insurance, check with your insurance provider.

And if you’re still keen on modifying your car, our comparison service lets you declare the changes you’ve made up front. So, you know the price you’re offered will include any modification you’ve made.

Compare car insurance quotes today and see what deals are available for modified cars.

Compare and save

What do I need to get a quote?

To compare quotes with us, you’ll need to give us some details, including:

Your car

To help us find the right cover, we'll need a few details about your car, such as the registration number, make, model, age, and how many miles you expect to drive each year.

We’ll also ask about any existing modifications on your car, even if your current provider already knows about them.

Your personal details

We'll need some information about you, including your name, age, address and occupation.

If you'd like to add any other drivers to your policy, we'll need their details too.

Your claims history

We'll ask about your driving record, including any no claims discount (NCD) you've built up, previous insurance claims and any motoring convictions.

It's important to provide accurate information, as incorrect details could affect the validity of your policy.

FAQs

What if my car comes with modifications?

If you’ve bought your new car from an authorised dealer and opted for extra features, such as alloy wheels, it shouldn’t affect your premium too much.

This is because they’ll have been fitted according to the manufacturer’s specifications.

However, if the modifications increase the value of your car, you may pay a slightly higher premium than you would for the basic model.

If you’re buying a second-hand vehicle that’s been modified, make sure you get all the details of the modification and pass them to your insurance provider.

Can you make modifications mid-policy?

Yes, you can make modifications to your car mid-policy. Just be sure to notify your insurance provider of any new modifications as soon as possible.

Don’t wait until it’s time to renew. If you neglect to inform them and you need to make a claim, your policy could be invalidated.

Be aware that your premiums could increase as a result of the modifications, so it’s worth weighing this up before deciding to make them.

How is the value of a modified car calculated?

Considering how varied modifications can be, there’s no straightforward way to calculate a modified car’s value.

This is why most modified car owners take out an agreed-value policy with their chosen insurance provider.

It means that you and your provider agree on an amount they’ll pay out if your car is written off, regardless of its original market value.

Will I need specialist modified car insurance?

Most mainstream insurance providers should be able to cover basic modifications. But heavily modified vehicles may need specialist modified car insurance.

Sam Wilson
Reviewed 15 Oct 2026 bySam WilsonInsurance expert

Sam Wilson is Head of Commercial Finance at Compare the Market and one of our core insurance experts on motor, home, van, motorbike and pet insurance products.

With over seven years at Compare the Market, Sam has a detailed understanding of how customers shop for insurance, what drives differences in premiums, and how small changes — such as shopping around at renewal or reviewing cover — can make a meaningful difference to what people pay.

Sam regularly comments in national and trade media on insurance costs, value for money and consumer savings, helping people understand how to get a good deal without focusing on price alone.

Methodology

1 Correct as of October 2026.

2Based on Trustpilot ratings (October 2026).

3Based on 51% of customers who compared quotes for this type of policy in June 2026.

4Based on 51% of customers who compared quotes for this type of policy in August 2026.