Voluntary vs Compulsory Excess Explained UK 2026

Last reviewed: 26 April 2026

What the compulsory excess is and how insurers set it

The compulsory excess is the portion of any claim the policyholder must contribute, set by the underwriter at policy inception. It applies to every claim regardless of fault, and it cannot be reduced by the policyholder, it is a condition of the underwriting, not a choice.

Compulsory excess levels reflect the insurer's actuarial assessment of the policyholder's risk profile. The standard compulsory excess for a low-risk driver on a standard vehicle typically ranges from £150 to £300. The same insurer will apply higher compulsory excesses for: young drivers (17 to 25) who face additional age-based compulsory excess loadings of £200 to £500 above the standard amount; vehicles in high Thatcham insurance groups where the expected repair cost per incident is elevated; drivers with recent fault claims in their history; and vehicles with non-standard modifications.

The compulsory excess is fixed for the policy year at inception. It cannot be reduced by paying a higher premium or by any other mechanism. Where the compulsory excess appears too high for a given driver profile, the only remedy is to seek alternative quotes from other insurers who apply different compulsory excess structures for the same risk profile.

The compulsory excess applies to all claims under the policy. A windscreen replacement claim may carry a separate, lower windscreen compulsory excess, commonly £75 to £100, which applies specifically to glass claims and is typically lower than the main policy compulsory excess.

What the voluntary excess is and how it works

The voluntary excess is an additional contribution to claims that the policyholder chooses at the time of quotation. Selecting a higher voluntary excess reduces the annual premium; selecting a lower voluntary excess (or zero voluntary excess) produces a higher annual premium.

The voluntary excess amount is locked in at the quotation stage. The policyholder cannot reduce the voluntary excess mid-term without requesting a formal mid-term adjustment from the insurer, which typically produces a premium increase and an administration fee. The voluntary excess is selected once and applies for the full policy year.

At the point of any claim, both excesses apply cumulatively. The total excess, compulsory plus voluntary, is deducted from the claim settlement. If the insurer pays a £5,000 repair and the total excess is £750 (£300 compulsory plus £450 voluntary), the policyholder receives a net settlement or payment of £4,250 toward the repair, with £750 of the cost borne by the policyholder.

The non-linear relationship between voluntary excess and premium savings

The actuarial relationship between voluntary excess and premium is not linear, increasing the voluntary excess by £100 does not consistently produce a £100-proportional premium reduction. In practice, insurer pricing engines respond to excess in a non-linear way that produces some excess increments as disproportionately good value.

A common pattern: moving from zero voluntary excess to £250 voluntary excess produces a larger percentage premium reduction than moving from £250 to £500. The reason is actuarial: the zero-excess pool contains a higher proportion of drivers who expect to make small, frequent claims, draining them of the entire claim value without excess exposure. An insurer charging the same premium to a £250-voluntary-excess policyholder knows that small claims (under £250) will not be submitted, substantially changing the expected claim cost profile.

This means that for policyholders comparing voluntary excess options, the first £200 to £300 of voluntary excess often provides the most premium-per-pound of excess saving. Incremental voluntary excess increases beyond £500 typically produce diminishing returns, the premium reduction per additional £100 of excess shrinks.

The ABI's 2025 motor insurance claims data indicates the average motor insurance claim cost is approximately £3,500 (verify current ABI data at publication). For claims of this average size, a total excess of £500 to £750 is a material but manageable self-insured component; a total excess of £1,500 or above requires careful assessment of out-of-pocket funding capacity.

FCA price walking ban implications for excess structures

The FCA's General Insurance Pricing Practices rules (PS21/5, effective January 2022) prohibit insurers from offering renewal premiums that exceed the equivalent new-customer price for the same risk. These rules apply to the full premium structure including any excess-related discounts.

The price walking ban means that the excess reduction strategy, increasing voluntary excess to reduce premium, is now applied consistently between new and renewing customers. Before January 2022, some insurers applied more generous excess discounts to new customers than to renewing customers; the FCA's reforms prohibited this differential treatment.

For policyholders comparing renewal quotes with open-market alternatives, excess structures should be compared on a consistent basis, the same voluntary excess across all quotes being compared. A quote at £500 voluntary excess from one insurer is not directly comparable to a quote at £250 from another without adjusting to a common excess level.

Choosing the optimal voluntary excess: the financial calculation

The financially optimal voluntary excess depends on two variables: the annual premium saving from the excess increase, and the probability-weighted expected cost of self-insuring the excess gap.

A policyholder considering a move from £250 to £500 voluntary excess who is offered a £60 annual premium saving needs to assess: how likely is it that a claim will be made during the policy year, and how often the £250 additional self-insured gap will materialise as an out-of-pocket cost. For a low-risk driver with a clean history driving 5,000 miles per year, a claim probability of perhaps 5 to 10 percent means the expected additional cost of the higher excess is £12.50 to £25 per year (5–10 percent probability × £250 additional excess). The £60 premium saving substantially exceeds this expected cost, the higher excess is financially rational.

For a young driver with a statistically higher claim probability of 20 to 30 percent, the expected additional cost of the same excess increase is £50 to £75 per year, closer to or exceeding the premium saving. The calculation narrows the margin and requires individual assessment.

Key Figures

Frequently Asked Questions

What is the difference between compulsory and voluntary excess?

The compulsory excess is set by the insurer and cannot be changed. The voluntary excess is an additional amount you choose at quotation to reduce your annual premium. Both are deducted from any claim settlement, your total excess at claim time is compulsory plus voluntary.

Can I reduce my compulsory excess by paying more?

No. The compulsory excess is set by the underwriter and is a condition of cover, not a choice. To access a lower compulsory excess for the same risk profile, compare quotes from multiple insurers, different underwriters apply different compulsory excess structures.

Does the excess apply to every claim?

Yes. The total excess, compulsory plus voluntary, is deducted from every claim settlement, regardless of fault. Windscreen claims typically carry a separate, lower windscreen excess rather than the main policy excess.

Is a higher voluntary excess always worth choosing?

Not always. The financial value of a higher voluntary excess depends on the annual premium saving and your probability of making a claim. For low-risk drivers with clean records and modest mileage, a higher voluntary excess often provides good premium-saving value. For higher-risk profiles with elevated claim probability, the analysis is more nuanced.

What happens if I cannot afford my excess when making a claim?

The excess is deducted from the claim settlement rather than paid separately in most cases, the insurer pays the repair cost minus the excess, or deducts the excess from a cash settlement. If the claim cost is less than the total excess, the insurer pays nothing and the claim is self-funded. Ensure your voluntary excess is set at a level you can genuinely fund if a claim arises.

Sources & Verification

• ABI Motor Insurance data: https://www.abi.org.uk
• FCA, General Insurance Pricing Practices (PS21/5): https://www.fca.org.uk/publications/policy-statements/ps21-5-general-insurance-pricing-practices
• Road Traffic Act 1988, section 143: https://www.legislation.gov.uk/ukpga/1988/52
• HMRC Insurance Premium Tax: https://www.gov.uk/guidance/insurance-premium-tax
• BIBA, Find a specialist broker: https://www.biba.org.uk/find-insurance/
• FCA Register: https://register.fca.org.uk
• gov.uk, Driving without insurance: https://www.gov.uk/vehicle-insurance/penalty-for-driving-without-insurance

This article is for informational purposes only and does not constitute financial advice. Always verify rates with official sources before making any financial decision.