A codicil to a will is a short legal document that amends an existing will without replacing it, letting you change one or two provisions while leaving the rest of the original document intact. It has to be executed with the same formalities as the will itself, which is why most states’ probate statutes treat a codicil and a will as the same kind of instrument.
When a Codicil Is the Right Tool
Codicils work best for narrow, specific changes. Common uses include correcting a beneficiary’s legal name after a marriage or divorce, swapping out an executor who can no longer serve, redirecting a specific bequest like a piece of jewelry or a vehicle, adding a charitable gift, or fixing an error such as a misspelled name or wrong address.
The thread running through all of these is that the overall structure of your estate plan stays the same. You are tweaking details at the margins, not reshaping the plan.
When to Write a New Will Instead
There is no legal cap on how many codicils you can attach to a single will, but practical limits arrive quickly. Each codicil the executor and probate court must read alongside the original adds another layer of potential confusion. If a judge decides accumulated amendments make your wishes unclear, parts of the will can be treated as invalid, which has the same effect as having no plan for those assets.
A new will is the better choice when you are changing multiple sections at once, overhauling how the bulk of your estate gets distributed, or modifying both beneficiaries and executor in the same round of updates. Major life events usually push past what a codicil can cleanly handle: a second marriage, the birth of additional children, a significant change in your finances, or a move to a different state with different probate rules.
A workable rule: if the changes would affect more than one or two paragraphs of the existing will, or if you already have a codicil or two attached, start over. The cost difference is usually small. Professional fees for a simple codicil typically run between $100 and $500 depending on location and the attorney’s experience, and a new simple will often falls in a similar range.
Legal Requirements for a Valid Codicil
Because the Uniform Probate Code and most state statutes define “will” to include “codicil,” the execution requirements are identical. A codicil that falls short of those standards can be thrown out in probate.
Testamentary Capacity
You must have testamentary capacity at the moment you sign. That means you understand what you own, who would normally inherit from you, and what the codicil does to your estate plan. A codicil signed during a period of serious cognitive decline is vulnerable to challenge even if the original will was perfectly valid years earlier.
No Undue Influence
You must also be acting freely. Undue influence occurs when someone in a position of trust or authority pressures you into making changes that reflect their wishes rather than yours. Most states let a challenger raise a presumption of undue influence by showing that someone in a confidential relationship with you, such as a caregiver, family member, or financial advisor, benefited from suspicious changes. Once the presumption is triggered, the burden shifts to the person who benefited to prove the changes were legitimate.
Witnesses
Under the Uniform Probate Code framework adopted by roughly half the states, a codicil must be in writing, signed by you (or by someone else at your direction and in your presence), and signed by at least two witnesses who watched you sign or heard you acknowledge your signature. Witnesses should ideally not be beneficiaries. An interested witness does not automatically invalidate the document in most states, but a gift to that witness may be voided unless additional disinterested witnesses also signed or the witness can prove no fraud or manipulation occurred. Use witnesses who have nothing to gain.
Holographic Codicils
Roughly half the states recognize holographic wills, meaning handwritten documents that do not require witnesses. Where allowed, a holographic codicil follows the same rules: the material provisions and your signature must be in your own handwriting, with no witnesses or notary required. Holographic documents face heavier scrutiny in probate and are more likely to be challenged on authenticity or capacity grounds. If witnesses are available, use them regardless of whether your state requires them.
What to Put in the Codicil
A codicil needs enough specificity that no one can reasonably argue about what you intended. Start with your full legal name, your address, and the exact date the original will was signed. If you already have earlier codicils attached, reference those too, so the court can reconstruct the full history of your estate plan.
Identify the exact provisions you are changing by article, section, or paragraph number. Vague references like “the part about my house” invite litigation. State clearly whether you are replacing a provision, adding to it, or revoking it entirely. For a redirected gift, you might write that a specific paragraph of the original will is replaced with new language directing a cash gift to a named individual at a stated address.
Include the full legal names and current addresses of any new beneficiaries. If you are redirecting a specific asset, describe it precisely, with account numbers for financial assets and legal descriptions for real property. The more detail, the less room for disputes among heirs.
Every codicil should include a confirmation that all other provisions of the original will remain unchanged. That single sentence prevents arguments that you intended broader changes than you actually made.
Signing, Self-Proving Affidavit, and Storage
The signing process is a miniature version of executing the original will. You sign the codicil in front of your witnesses, they watch you sign (or you tell them you have already signed), and then they each sign. Everyone should be in the same room at the same time. Some states have adopted remote online notarization rules that may allow witnesses to participate by audio-video technology, but the rules vary and not every state extends remote notarization to estate planning documents.
A self-proving affidavit is a sworn statement attached to the codicil that lets it be admitted to probate without pulling your witnesses into court to testify. Under the Uniform Probate Code model, you and your witnesses sign an affidavit before a notary public declaring that you signed the codicil willingly, that you were of sound mind and at least 18 years old, and that no one pressured you. The notary affixes an official seal. Most states allow you to add this affidavit either at the time of signing or later. Statutory notary fees for a single acknowledgment vary by state, with maximums ranging from about $2 to $25.
Once signed, store the codicil with or physically attached to the original will. A separated codicil can be overlooked entirely, leaving the court to follow outdated instructions. Tell your executor and at least one trusted family member where both documents are stored. If you use a safe deposit box, make sure someone besides you has access, since boxes are sometimes sealed temporarily after a death.
Revoking a Codicil
You can revoke a codicil in three ways: execute a new codicil that expressly revokes the earlier one, execute an entirely new will that supersedes everything, or physically destroy the codicil with the intent to revoke it. Tearing it up, burning it, or shredding it all work, but intent matters. Accidental damage does not count.
Revoking a codicil generally restores the original will to its unmodified state. The changes the codicil made are erased, and the will is read as if the codicil never existed. This is different from revoking an entire second will that replaced a first will. In that situation, many states do not automatically revive the first will unless you clearly intended it to come back into effect. If you want to undo a codicil and return to your original plan, destroying the codicil alone is usually enough. If you wrote a whole new will and now regret it, the path back is more complicated.
How Codicils Get Challenged in Court
Codicils face the same challenges as wills, but the timing makes them more vulnerable. A codicil is often signed years after the original will, when the testator is older and potentially in declining health. That gap gives challengers more ammunition.
The three main grounds for contesting a codicil are improper execution, lack of capacity, and undue influence. Improper execution means the document did not meet the technical requirements: not enough witnesses, no signature, or failure to follow the state’s specific formalities. Lack of capacity means you were not mentally competent on the date you signed. Undue influence means someone manipulated you into making changes you would not have made on your own.
Codicils also introduce a risk that full rewrites avoid: conflicting instructions. If the codicil does not clearly state which provisions of the original will it replaces, a court has to interpret the relationship between the two documents, and that ambiguity alone can fuel litigation. A well-drafted codicil explicitly states what it replaces and confirms everything else remains unchanged.
One Boundary: Divorce Does Not Do What People Assume
More than 40 states have some form of automatic revocation statute that kicks in when you divorce. Under the Uniform Probate Code approach, divorce automatically revokes any provision in your will that benefits your former spouse or your former spouse’s relatives who are no longer related to you after the divorce. It also revokes any nomination of your ex-spouse as executor, trustee, or guardian. The will is read as though your former spouse predeceased you.
The automatic revocation handles your ex-spouse, but it does not add a new partner, update guardianship for children from a new relationship, or redistribute assets the way you would actually want. A codicil might handle one or two of those updates, but a divorce usually changes enough about your life that a new will is the cleaner path.