What it does
A higher deductible (called excess in the UK) lowers your premium, but you pay more of each claim yourself. Whether that is a good trade depends on how often you claim and how big the claims are. This tool compares two quotes and shows the saving, the break-even and the range of outcomes.
It is written for car insurance but works the same for home and health deductibles. Next, see whether a single claim is worth making with claim or pay for the repair yourself?, or check what your car is insured for with IDV and NCB calculator (India).
How to use it
- Type the yearly premium and the deductible for each quote. The numbers shown are examples: change them to yours.
- Say how often you claim, either as claims a year or as “1 claim every N years”.
- Give the typical claim (the middle one) and the size that 1 in 10 claims goes above.
- Read the result. The 10,000 imagined runs appear a moment after you stop typing.
What each setting does
- Claims a year: 0.1 means about one claim in ten years.
- Typical claim: half of claims are smaller, half bigger.
- 1 in 10 claims is bigger than: sets how fat the tail of big claims is.
- Years to look at: how long you keep the choice.
Worked example
Quote A costs 1,200 with a 500 deductible, quote B costs 1,000 with a 2,500 deductible. B saves 200 a year, and one full claim costs 2,000 more, so one claim uses up 10 years of savings. With claims 0.1 a year, a typical claim of 100,000 and 1 in 10 above 200,000, the break-even is 0.1 claims a year, so the expected saving is about zero.
FAQs
Does it tell me which to buy? No. It shows what each choice costs on average and in good and bad luck.
Why a chance below 100% when the saving is positive? One big claim can wipe out many years of savings.
Are my numbers stored? No, nothing leaves this page.
How it’s worked out: saving a year = premium A − premium B; extra cost per claim = E[min(claim, high deductible)] − E[min(claim, low deductible)]; break-even rate = saving ÷ extra cost per claim.
Where the numbers come from
- Standard actuarial model: Poisson claim counts and lognormal claim sizes; expected cost per claim is the mean of the claim capped at the deductible (limited expected value). The numbers on the page are examples, not quotes.
Standard scientific values, such as constants, atomic weights and melting points, are facts found in every textbook; we name where ours were checked. If you are an author or publisher and want a value, a credit or a table changed or removed, tell us and we will act quickly.
Last updated 2026-11-10.