A codicil is a supplementary document that amends a will you have already made, rather than rewriting it. It sits alongside the original will, changes only the points it names, and leaves everything else untouched. To be valid in England and Wales it must be signed and witnessed in the same way as a will. It suits small, clear changes.
How to make one valid, what it can and cannot do, when a fresh will is safer, and the mistakes that cause disputes are all below. Rules are current as at August 2026, subject to change.
What is a codicil, exactly?
A codicil is an official, standalone document that alters a will you have already signed, without replacing it. Once a will is signed and witnessed you cannot amend it by writing on the page; the only valid route is a separate codicil, executed with the same formality as the will itself (gov.uk, updating your will, as at August 2026, subject to change).
A codicil does not cancel the will. It overrides only the clauses it names, and the will and any codicils are then read together as one set of instructions. So a codicil must name the will it amends, by date, and describe the change precisely.
How do you make a codicil legally valid?
A codicil carries the same signing rules as a will. It must be in writing, signed by you, and witnessed by two independent people who watch you sign and then sign themselves. Miss any of these and the codicil can be worthless, leaving the original will to stand unchanged.
- Write it as a separate document. Head it as a codicil to your will and state the date of the will it changes. Do not mark or write on the signed will itself, as that can call the will into question (gov.uk, updating your will, as at August 2026, subject to change).
- Set out the change clearly. Name the clause you are altering and say exactly how, for example revoking one gift and substituting another, or replacing a named executor. Confirm the rest of the will stands.
- Sign in front of two witnesses. Both must be present together, watch you sign, and sign themselves while you watch. Neither witness, nor their spouse or civil partner, may be a beneficiary, or that person can lose their gift (gov.uk, who can witness a will, as at August 2026, subject to change).
- Store it with the will, unattached. Keep the codicil in the same place so both are found together, but do not staple or pin it to the will. A codicil that goes missing can defeat the change you meant to make.
A codicil need not be registered, and you are not required to use a solicitor. A home-made codicil is legal, but a small error in wording or witnessing can undo it, which is why many take advice. Our guide to making a will without a solicitor covers the same execution rules.
What can a codicil change, and what can it not?
A codicil is built for small, targeted edits: swapping an executor, adding or removing a specific gift, correcting a misspelled name, or adjusting a legacy amount. It works best when the shape of the will stays the same and only a detail moves.
It is a poor tool for anything structural. Redirecting who inherits the bulk of the estate, adding trusts, or making several changes at once are better done in a new will. The table below sorts common changes by the cleaner route.
| Change you want to make | Codicil | New will |
|---|---|---|
| Replace one executor | Suitable | Optional |
| Add or remove a single small gift | Suitable | Optional |
| Correct a name or a minor error | Suitable | Optional |
| Change who inherits the residue (the bulk) | Avoid | Recommended |
| Add or restructure a trust | Avoid | Recommended |
| Two or more changes at once | Avoid | Recommended |
| Update after marriage, divorce or a new child | Avoid | Recommended |
General guidance for England and Wales, based on gov.uk, updating your will, as at August 2026, subject to change.
Codicil or a new will: which should you use?
Choose a codicil only for a single, clear change to a will that is otherwise right. For anything more, gov.uk itself says to make a new will, which revokes all previous wills and codicils and leaves one clean document (gov.uk, updating your will, as at August 2026, subject to change). A useful rule of thumb: if you would need more than one codicil, or the change touches who gets the residue, write a new will instead.
What people get wrong about codicils
Treating the codicil as the standard fix for minor changes is now dated. Since wills have been drafted on computers, replacing one costs little more than amending it, and most will writers now redraft rather than bolt on a codicil. Three mistakes cause most of the trouble.
Stacking codicils. There is no legal limit, but each one is another document a reader must reconcile with the last, so the risk of contradiction and challenge climbs. One at most; beyond that, write a new will.
Careless witnessing. Using a beneficiary, or their spouse, as a witness does not void the codicil, but it can strike out that person's gift. Both witnesses must be independent and present together, the same standard as the will.
Letting it drift from the will. A codicil kept apart, or attached and later torn off, can go unread or raise questions about tampering. Keep both together, unattached, and tell your executor where they are. Disputes over a codicil mirror those over a will, covered in our guide on how to contest a will.