The average clause: how underinsurance shrinks a small claim

There is a settled way of talking about the average clause. It is worth asking how much of it survives contact with the detail.

The mechanism in one line

Under an average clause, the insurer pays the claim multiplied by the ratio of the sum insured to the true value at risk. Declare sixty thousand of contents that are actually worth a hundred thousand and you have declared sixty per cent of the risk.

A five thousand claim is then settled at three thousand, less any excess, even though the loss is far below the sum insured. The clause exists because you paid premium on sixty per cent of the risk, so you are treated as self-insuring the rest.

Why it surprises people

The intuition is that a sum insured is a ceiling, so any claim below it should be paid in full. Average converts it into a proportion instead, which is a fundamentally different contract and is rarely explained at the point of sale. It therefore bites hardest on modest, ordinary claims made by people who never expected the total figure to be relevant.

Put simply, this is one of the few clauses that costs money on claims that had nothing to do with the mistake.

Where it applies and where it does not

Average is standard in many property wordings and is applied to both buildings and contents sections. Some consumer policies waive it, or apply it only where underinsurance exceeds a stated margin such as ten or fifteen per cent.

A growing number of insurers offer sum-insured-not-required or unlimited buildings cover, which removes the issue by removing the figure. Which applies to you is a wording question, and the answer is not consistent across a market.

Getting the contents figure right

The honest method is a room-by-room count at replacement cost, not at what you paid or what you think it is worth second hand. Clothing, kitchen equipment, tools, books and children's belongings are the categories almost universally undercounted. Photographing each room and its open cupboards takes twenty minutes and doubles as claim evidence.

Most households that do this once find the true figure is substantially higher than their declared one.

Getting the buildings figure right

Buildings sums insured should be rebuild cost including demolition, debris removal, professional fees and access. Construction costs in many markets have risen sharply, so a figure set several years ago and merely index-linked may still be short. Non-standard construction, listed status and difficult access all raise rebuild cost well above a generic per-square-metre estimate.

Surveying bodies in several countries publish rebuild calculators, and a professional assessment is available for unusual properties.

Reviewing it on a schedule

The natural triggers are renovation, an extension, a large purchase, or inheriting anything substantial. Automatic index-linking helps with general inflation and does nothing about a new kitchen or a bought sofa. A five-minute annual review at renewal is the whole discipline required.

Put simply, where a property or a collection is unusual, a professional valuation is the sensible route rather than an estimate.

The takeaway

Underinsurance is not a ceiling problem. It is a percentage taken off every claim you make.

The version you keep doing is the version that works.