A codicil is a legal document that changes, adds to or removes part of an existing will, without replacing the whole will. It sits alongside your original will and is read together with it, so both documents take effect as one set of instructions.
In England and Wales a codicil is signed and witnessed to the same standard as the will it amends (gov.uk, Making a will: update your will, as at August 2026, subject to change). It is a way of making a small, clearly defined change, for example swapping an executor or adjusting a gift, while leaving the rest of your will untouched. This guide explains what a codicil does, when it tends to be the right tool and when a fresh will is the better route.
What does a codicil do?
You cannot simply cross out a line in a signed will and write in a new one. Handwritten alterations made after a will has been signed are generally not valid unless they are themselves signed and witnessed (gov.uk, as at August 2026, subject to change). A codicil is the formal alternative. It refers to the original will by date, sets out the specific change, and confirms that the rest of the will stands.
Typical uses include changing an executor, updating a specific cash gift or item, adding or removing a beneficiary, appointing or changing a guardian for young children, or correcting a name after a marriage or divorce. There is no legal limit on how many codicils you can add to a will (gov.uk, as at August 2026, subject to change), though several stacked on top of each other can become hard to follow.
When is a codicil the right choice?
A codicil tends to suit a single, self-contained change to an otherwise sound will. If the underlying will still reflects your wishes and the amendment is small, a codicil can be a proportionate way to keep it current. The table below sets out the kinds of change people commonly make.
| Change | Often suits a codicil? |
|---|---|
| Replacing one executor | Yes, a defined single change |
| Adjusting one cash gift or leaving a specific item | Yes |
| Adding a guardian for a child | Yes |
| Rewriting who inherits the bulk of the estate | Usually a new will |
| Several changes at once | Usually a new will |
| Change after marriage, divorce or a new child | Often a review and new will |
Note that in England and Wales marriage or civil partnership usually revokes an existing will unless the will was made in contemplation of that marriage, and this is one situation where reviewing the whole will matters rather than patching it (gov.uk, as at August 2026, subject to change).
Codicil or a new will?
For anything beyond a minor amendment, official guidance is that you should make a new will rather than a codicil (gov.uk, as at August 2026, subject to change). A new will can revoke all previous wills and codicils, which leaves a single, clean document for your executors to work from. The comparison below sets out the practical trade-offs.
| Consideration | Codicil | New will |
|---|---|---|
| Best for | One small, clear change | Several changes or a rethink |
| Documents your executor reads | Two or more, read together | One |
| Risk of confusion or conflict | Higher as codicils accumulate | Lower |
| Signing and witnessing | Two witnesses, as for a will | Two witnesses |
| Revokes earlier documents | Only the parts it changes | Can revoke all earlier wills and codicils |
The drafting effort for a short new will is often not far above that of a well-drawn codicil, which is part of why a fresh will is frequently the tidier answer. Our related guide on how to write a will sets out what a full will typically covers.
How to make a codicil legally valid
A codicil must meet the same formal rules as a will under section 9 of the Wills Act 1837 (legislation.gov.uk, Wills Act 1837 s.9, as at August 2026, subject to change). In practice that means the following.
| Requirement | What it means |
|---|---|
| In writing | The codicil is a written document, dated, and refers to the will it amends |
| Signed by you | You sign it, intending by that signature to give effect to it |
| Two witnesses present | Two witnesses have a clear view of you signing |
| Witnesses sign | Each witness signs while you watch; they need not sign at the same moment as each other |
| Witnesses are independent | A witness, or their spouse or civil partner, generally cannot be left anything under the will |
Source: gov.uk, Making a will: update your will and gov.uk, make sure your will is legal, as at August 2026, subject to change.
If a beneficiary, or their spouse, acts as a witness, the gift to that person can fail even though the codicil itself remains valid. Choosing witnesses who take nothing under the will avoids that problem.
Storing a codicil with your will
Because a codicil only makes sense when read with the will it changes, the two need to be stored together and both need to be found after death. Do not staple, pin or reattach anything to the original will, as marks and removed staples can raise questions at probate about whether another document was once attached. Keep the will and codicil in the same place, and tell your executors where they are. When the time comes, your executors will need the original documents to apply for probate, the legal authority to deal with the estate, which our guide on what probate is explains further.
Cost and timescale
There is no government fee to make a codicil itself; a codicil is a private document, not something registered with a court or public body. Costs, where they arise, are the fees a will writer or solicitor charges for drafting, which vary with complexity. Any fee is usually agreed before work begins, and at Fairchild Oldfield we set out costs in writing first.
A codicil takes effect only on death, in the same way as the will. It is worth knowing that a fee does apply later, when your executors apply for probate: in England and Wales the probate application fee is £526 for an estate valued over £5,000, with no fee where the estate is £5,000 or less (gov.uk, Applying for probate: fees, as at August 2026, subject to change). That fee relates to administering the estate, not to making the codicil.
Common mistakes to avoid
- Amending the will by hand. Crossing out or writing on a signed will is generally ineffective unless the change is signed and witnessed (gov.uk, as at August 2026, subject to change).
- Using a beneficiary as a witness. This can void the gift to that person.
- Stacking many codicils. Several codicils on one will can conflict and confuse; a new will is often clearer.
- Losing the link. A codicil that cannot be found, or is separated from the will, may not take effect as intended.
- Patching after a major life change. After marriage, divorce or a new child, a full review through estate planning often serves better than a single amendment.
Codicils in Scotland and Northern Ireland
This guide describes the law of England and Wales. Scotland has its own succession law, including different rules on the validity of wills and legal rights that can entitle a spouse and children to a fixed share of an estate, so the treatment of codicils differs there. Northern Ireland has a separate but broadly similar system to England and Wales. If your will or estate touches more than one jurisdiction, it can be worth taking advice in each.
Frequently asked questions
What is a codicil to a will in simple terms?
It is a separate legal document that changes or adds to an existing will without replacing it. The codicil and the original will are read together and take effect as one set of instructions. It must be signed and witnessed to the same standard as a will (gov.uk, as at August 2026, subject to change).
Does a codicil need to be witnessed?
Yes. A codicil is signed and witnessed in the same way as a will: you sign it in front of two independent witnesses, who then sign while you watch (gov.uk, as at August 2026, subject to change). A witness, or their spouse or civil partner, generally cannot be a beneficiary, or the gift to them can fail.
Is a codicil as legally binding as a will?
A codicil that meets the formal requirements of section 9 of the Wills Act 1837 has the same legal standing as the will it amends (legislation.gov.uk, as at August 2026, subject to change). If it is not properly signed and witnessed, it may not be valid, and the original will stands unchanged.
How many codicils can you add to a will?
There is no legal limit on the number of codicils (gov.uk, as at August 2026, subject to change). In practice, several stacked codicils can become hard to follow and may conflict, so gov.uk advises making a new will for major or multiple changes.
How much does a codicil cost?
There is no government fee to make a codicil, as it is a private document rather than one registered with a court. Any cost is the drafting fee a will writer or solicitor charges, which varies with complexity and is usually agreed in advance. A separate probate application fee of £526 applies later for estates over £5,000 when executors administer the estate (gov.uk, as at August 2026, subject to change).
Can I write a codicil myself?
It is possible to write one yourself, but the same formal rules apply, and small errors in wording, signing or witnessing can make it ineffective or cause a gift to fail. Because a codicil interacts with the existing will, many people ask a will writer or solicitor to prepare it so the two documents work together as intended.
Should I use a codicil or make a new will?
A codicil suits a single, clear change to a will that still reflects your wishes. For several changes, a significant rethink, or after a major life event, gov.uk advises a new will that revokes earlier wills and codicils (gov.uk, as at August 2026, subject to change). This is general information, and the right choice depends on individual circumstances.