# Underinsurance and the guarantee against underinsurance

> If your sum insured is too low, you are only reimbursed part of your loss. This is how the proportionality rule works.

*Gepubliceerd: 2026-06-08* · *Categorie: uitleg*

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Underinsurance is a pitfall that can prove painful in large losses. It arises when the sum insured is lower than the actual value of your property.

## The proportionality rule

If you are underinsured, the insurer reimburses the loss proportionately. Example: if your contents are worth EUR 100,000 but insured for EUR 60,000, you are in principle reimbursed 60% of every loss — even a small one.

## Guarantee against underinsurance

Many policies offer a **guarantee against underinsurance**: if you had the sum insured determined correctly using a valuation or contents calculator, the insurer will not apply the proportionality rule. Check whether you have this guarantee.

## The 115% margin

Under some conditions, the sum insured is automatically increased in the event of a loss, up to a maximum of 115% of the insured amount. Only above that does the proportionality rule come into play again.

> **Please note** — Whether underinsurance applies and how it is calculated is a frequent point of dispute. Have this checked carefully; it can make a difference of thousands of euros.