What Is a Codicil to a Will? When and How to Use One

A codicil is a separate legal document that makes changes to your existing will. It was introduced by the Wills Act 1837 and must follow the same signing and witnessing rules as a full will. You can use a codicil to add, remove, or amend specific instructions — for example, changing an executor, updating a gift, or adding a new beneficiary.

What makes a codicil legally valid

A codicil only works if it meets the same formalities as the will it modifies. Under the Wills Act 1837, you must sign the codicil in the presence of two independent witnesses, who then sign it themselves while you watch. The witnesses cannot be beneficiaries under the will or codicil, and they cannot be married to or in a civil partnership with a beneficiary. If a witness stands to inherit, that specific gift fails — the rest of the codicil remains valid.

The codicil must refer clearly to the will it amends. Most codicils begin with a statement like "This is the first codicil to the will dated 10 March 2019 of John Smith of 42 Oakwood Road, Leeds". That reference links the two documents. If you make multiple codicils over time, number them sequentially (first codicil, second codicil) and date each one. When probate is granted, the executor must submit the original will and all codicils together.

You do not need a solicitor to draft a codicil, but you do need to get the wording and execution right. A poorly worded codicil can create confusion or conflict with the original will, and an improperly signed codicil is invalid. Many solicitors and will-writing services charge £50–£150 to draft and supervise a simple codicil, which can be cheaper than rewriting the entire will.

When a codicil is the right tool

Codicils work best for small, straightforward changes. Common uses include replacing an executor who has died or no longer wishes to act, updating a specific cash gift (for example, increasing a legacy from £5,000 to £10,000), adding a new beneficiary to receive a particular item, or removing a gift that no longer applies because you have sold the asset or the beneficiary has died.

Codicils were more popular before home computers and word processors. Retyping a will by hand or on a typewriter was time-consuming, so a one-page codicil saved effort. Today, most wills are stored digitally, making it just as easy to produce a new will with all changes incorporated. Despite this, codicils remain legally valid and are still used, particularly by older testators or solicitors working with clients who prefer not to revisit the entire will.

If you need to make only one or two discrete changes and the rest of your will remains exactly as you want it, a codicil can be quicker and cheaper. However, if you are making multiple changes, altering the structure of your estate, or adding complex provisions such as trusts in your will, a new will is usually clearer and safer.

When you should write a new will instead

Writing a fresh will is almost always better than using a codicil if you are making more than two or three changes, if the changes affect the overall distribution of your estate, or if your original will is more than a few years old. A new will revokes all previous wills and codicils, giving you a single, up-to-date document that reflects your current intentions without cross-referencing older paperwork.

Life changes such as marriage, divorce, the birth of children or grandchildren, or a significant shift in your assets usually call for a new will. Marriage automatically revokes any will made before the wedding unless the will was explicitly made in contemplation of that marriage. Divorce does not revoke a will, but it does remove your former spouse as a beneficiary and executor — you should still write a new will to appoint replacements and clarify your wishes.

If you have already made one or two codicils, adding a third creates a chain of documents that must all be read together. This increases the risk of ambiguity, contradiction, or oversight. Executors and probate registries must locate and interpret the will plus every codicil, which can delay probate. A single consolidated will is easier to administer and less prone to challenge. If someone wanted to contest your will, multiple codicils can provide more grounds for dispute — particularly if the handwriting, signatures, or dates raise questions about your mental capacity or undue influence at different times.

Cost is often similar. Many online will services and high-street solicitors charge £100–£200 for a straightforward single will, which is comparable to the cost of drafting a codicil. For a modest additional fee, you get a clean document that everyone can follow without cross-checking amendments.

How to prepare and sign a codicil correctly

Start by obtaining a copy of your current will and reading it carefully. Identify exactly what you want to change and write down the specific clause or paragraph. Draft the codicil using clear language. For example: "I revoke clause 4 of my will dated 10 March 2019 and substitute the following: I give £10,000 to my niece Sarah Jones of 7 Elm Street, Bristol." or "I appoint my daughter Emma Brown of 15 Park Avenue, Manchester, as an additional executor alongside my existing executors."

Include your full name and address at the top, state that this is a codicil to your will, and give the date of the original will. Number the codicil if you have made others before (for example, "This is the second codicil"). Sign and date the codicil at the end, in the presence of two witnesses who are both present at the same time. The witnesses must see you sign, then sign the codicil themselves while you watch. Each witness should write their full name, address, and occupation next to their signature.

Store the codicil with your original will in a safe place — not attached by staple or paperclip, as any marks on the will can raise questions during probate about whether pages were added or removed. Tell your executors where the codicil is kept. If you use a solicitor or bank to store your will, send them the codicil to hold alongside it. If you registered your will with the National Will Register or another service, update your entry to note that a codicil exists.

Common mistakes and how they cause problems

The most frequent error is failing to follow the signing and witnessing rules. If you sign a codicil without two independent witnesses present, or if a beneficiary witnesses it, the codicil is either invalid or the affected gift fails. Some people print a codicil, sign it at home, then post it to witnesses to sign separately — this does not satisfy the legal requirement that all three people must be together.

Another mistake is vague or contradictory wording. If a codicil says "I wish to leave more to my son" without specifying an amount or which gift is increased, the executors cannot give effect to your intention. If a codicil removes a gift but does not say what should happen to that asset instead, it may fall into the residue of your estate — the remainder after all specific gifts are distributed — which might not be what you intended.

People sometimes write multiple codicils over several years, forgetting what each one says. This can create a patchwork of conflicting instructions. For example, the first codicil might appoint a new executor, and the second codicil might revoke that appointment without realising the effect of the earlier change. Executors must then work out which instruction takes precedence, based on the order and wording of each codicil.

Handwritten additions or notes in the margin of a will are not valid codicils, even if you sign and date them. Any amendment to a will must be a separate document, properly executed. If you cross out or alter text in the original will, those changes are ignored unless you and your witnesses sign next to each alteration — and even then, the safest approach is to prepare a formal codicil or new will.

What happens to codicils during probate

When you die, your executors must locate the original will and all codicils. The probate registry requires the originals — photocopies are not accepted unless the originals are lost and you can provide evidence of their contents. The executors read the will and each codicil together to determine your final wishes. If there is any conflict, later codicils generally override earlier ones, and codicils override the original will where the two cannot be reconciled.

The probate application must list every codicil. If a codicil is discovered after probate is granted, the executors may need to apply to the court to admit it, which can delay the administration of your estate and increase costs. This is why it is important to store the will and all codicils together and tell your executors where to find them.

If you have concerns about someone challenging your will, be aware that each codicil is a separate opportunity for dispute. A challenger might argue that you lacked mental capacity when you signed a later codicil, or that you were unduly influenced, even if the original will was sound. Fewer documents mean fewer points of attack, which is another reason to consolidate your wishes into a single new will if you are making significant changes.

Practical alternatives to a codicil

Instead of amending your will, you can sometimes achieve the same result by changing how you own assets. For example, if you want to leave your house to a specific person, you could add them as a joint owner with a declaration of trust stating that they take your share on your death. This removes the house from your estate and avoids the need to update your will. However, this approach has risks — the other person owns part of the property immediately, which can affect inheritance tax, capital gains tax, and your ability to sell or remortgage.

Another option is to make lifetime gifts. If you want to increase what someone inherits, you can give them money or assets now, rather than waiting until you die. Gifts made more than seven years before your death are usually outside your estate for inheritance tax purposes. Be cautious with large gifts close to death, as they may still be taxable, and you must ensure you keep enough assets to live on.

For small personal items, some people write a letter of wishes to accompany their will. This is not legally binding, but it can guide your executors on who should receive specific possessions like jewellery, books, or photographs. A letter of wishes does not need to be witnessed and can be updated as often as you like without any formalities. However, executors are not obliged to follow it, so it works best for non-contentious items and as a supplement to, not a replacement for, clear instructions in your will.

If your main concern is ensuring funeral wishes are carried out, remember that a will is often not read until after the funeral. You can leave separate written instructions with your family or a trusted friend, or prepay a funeral plan, rather than relying solely on your will or a codicil.

Digital wills and codicils: a note on future changes

At present, all wills and codicils in England and Wales must be signed on paper in the presence of physical witnesses. The Law Commission has consulted on allowing electronic wills, including video witnessing and digital signatures, but no changes have been made to the law. During the Covid-19 pandemic, temporary regulations allowed a will to be witnessed over video link, but those rules expired in January 2024 and have not been extended.

If the law changes in future to permit digital wills, the same rules will almost certainly apply to codicils. Until then, you cannot make a valid codicil by typing it into a computer, sending it by email, or signing it electronically. You must print the document, sign it in pen, and have two witnesses sign it in your presence.

For digital assets such as online accounts, cryptocurrency, or social media profiles, a codicil is not usually the best tool. Most digital assets are controlled by terms of service rather than wills, and companies may not recognise instructions in a will or codicil unless you have also completed their legacy contact or account succession forms. You can appoint a digital executor in your will or codicil, but you should also leave a separate list of accounts, passwords, and instructions outside the will so your executors can act quickly.

When a codicil might fail or be challenged

A codicil can fail for the same reasons as a will: lack of valid execution, lack of testamentary capacity, undue influence, fraud, or a successful claim under the Inheritance (Provision for Family and Dependants) Act 1975. If someone challenges a codicil on the grounds that you did not understand what you were signing when you made it, the burden is on the person seeking to uphold the codicil to prove that you had capacity and intended to make those changes.

Testamentary capacity means you understood the nature of making a will or codicil, the extent of your assets, and the claims of people who might expect to inherit. If you had dementia or another condition affecting your mental capacity when you signed a codicil, a court may find it invalid even if the original will remains valid. This is why it is important to have a solicitor or other independent person present when signing a codicil if there is any doubt about your capacity, so they can provide evidence if needed.

Undue influence occurs when someone pressures or manipulates you into making a codicil that does not reflect your true wishes. This is difficult to prove, but the court will look at the circumstances: whether you had independent advice, whether the beneficiary was in a position of power or trust, and whether the codicil makes sense given your previous intentions. A codicil that suddenly and unexpectedly benefits a carer, a new partner, or someone who isolated you from family may attract suspicion.

Revoking a codicil without affecting your will

You can revoke a codicil without revoking the underlying will. The simplest way is to write a new codicil that begins "I revoke the codicil to my will dated [date] and confirm my will dated [date] in all other respects." This cancels the earlier codicil and restores the original will. You can also revoke a codicil by destroying it — tearing it up or burning it — provided you do so with the intention of revoking it. If someone else destroys it on your behalf, they must do so in your presence and at your direction.

Writing a new will automatically revokes all previous wills and codicils. The new will should include a standard revocation clause: "I revoke all former wills and codicils." This makes it clear that everything before the new will no longer applies. If you accidentally leave out the revocation clause, the new will may still revoke earlier wills by implication if it disposes of your entire estate, but it is safer to include the clause explicitly.

If you made a codicil but never signed it, or the witnesses did not sign properly, it has no legal effect and your will stands as it was. You do not need to do anything to revoke an invalid codicil — it was never valid in the first place. However, if you have a draft codicil that you decided not to use, destroy it to avoid confusion after your death.

Codicils and intestacy: what happens if you have no will

A codicil cannot create a will where none exists. If you die without a will, you die intestate, and intestacy rules determine who inherits. You cannot use a codicil to amend intestacy rules or to give specific gifts if you never made a will. You must write a full will, following all the signing and witnessing formalities, before a codicil can modify it.

If you write a codicil thinking it is a will, the codicil is invalid because it only operates as an amendment to an existing will. For example, if you write "I leave my house to my daughter" and sign it with two witnesses, but you have no will, that document is not a valid will because it does not contain the usual will provisions (such as appointing executors, disposing of residue, or revoking earlier wills) and it refers to itself as a codicil. The result is that you die intestate, and your house passes under intestacy rules rather than to your daughter.

This is why it is important to understand that a codicil is a supplementary document, not a substitute for a will. If you do not have a will, you need to make one. A codicil is only useful once a valid will is already in place.

Why clear instructions matter more than codicils

The ultimate purpose of a will — and any codicil to it — is to give your executors and family clear, legally binding instructions about what should happen to your estate. Whether you use a codicil, write a new will, or leave a letter of wishes, clarity is more important than the format. Ambiguous wording, missing information, or contradictory instructions can lead to disputes, delay, and legal costs that reduce what your beneficiaries receive.

If you are considering a codicil, ask yourself whether it will make your intentions clearer or create more questions. If the answer is the latter, a new will is almost always the better choice. Your executors will thank you for leaving a single, coherent document that they can follow without cross-referencing three or four pieces of paper.

Finally, review your will and any codicils regularly — at least every five years, or whenever your circumstances change. A will or codicil that made sense ten years ago may no longer reflect your wishes, your assets, or your family situation. Keeping your will up to date reduces the risk that someone will challenge it and ensures that your estate is distributed the way you intend.

This is general information, not legal advice. Wills and inheritance rules vary — for anything binding, use a regulated solicitor or will-writing service.