What Is a Codicil?

What it is

A codicil is a formal document that amends an existing will. Rather than replacing the whole will, it makes specific changes to it — adding a gift, removing a beneficiary, changing an executor — while leaving everything else intact.

It has exactly the same legal formalities as a will: it must be in writing, signed by the testator, and witnessed by two independent witnesses who are also present when the testator signs.

When a codicil works well

A codicil is appropriate for straightforward, limited changes. Classic examples: adding a specific gift you forgot to include, replacing an executor who has died or who has told you they do not want the role, or updating a cash gift to reflect a change in what you can leave.

If the change is small and clearly defined, a codicil avoids having to rewrite the whole document.

When a new will is better

For anything more substantial, writing a new will is usually the cleaner option. A new will revokes the old one with a revocation clause, removing any ambiguity about which version governs.

Codicils create risk when there are multiple of them, or when the changes interact with each other in ways that are not entirely clear. A will with two or three codicils attached to it can be harder to interpret than a single up-to-date document. Solicitors involved in probate spend real time untangling wills where codicils have created contradictions or gaps.

If you are making significant changes — a new spouse, a new child, a major change in assets, a decision to exclude someone — write a new will.

What happens after you add a codicil

The codicil and the original will are read together as a single document. Your executor needs both. Store the codicil with the original will and make sure your executor knows both documents exist.

If you have registered your will on the National Will Register, you should update the registration to note that a codicil exists.

Codicils and PureWill

PureWill lets you write a complete new will for £79. For most people, a new will is simpler than a codicil — there is no ambiguity, no risk of documents being separated, and no need to track which version of your will is current. If you need to change your will, the easiest approach is usually to start fresh.