The document used to add an addendum to a will is called a codicil: a short written amendment that references your existing will, states the specific changes, and is signed with the same formalities the will itself required. Once executed properly, the codicil becomes part of the will and controls wherever it conflicts with the original.
Before drafting one, it helps to know when a codicil is the right tool and when you should start over with a new will instead.
When an Addendum Is the Right Tool
A codicil works well for isolated, minor updates to an otherwise sound estate plan. Swapping executors, adjusting the dollar amount of a single bequest, updating a beneficiary’s legal name after marriage, or adding a charitable gift are the kinds of edits it handles cleanly. The original will stays intact, and the codicil overrides only the specific provisions it addresses.
A new will is the better choice when changes are significant or numerous. Marriage, divorce, the birth of a child, or a move to a different state usually justifies starting fresh. So does a major shift in your assets, such as selling a business, receiving a large inheritance, or buying real property that changes the overall picture of your estate. If you want to remove a beneficiary entirely, a full rewrite makes your intent far harder to challenge than a codicil that sits alongside a document still naming that person.
Stacked codicils are where things tend to go wrong. Each amendment is a separate document that an executor and probate court must reconcile with the original will and every prior codicil, and later codicils sometimes fail to reference earlier ones. If you already have one codicil and need another round of changes, that is a good signal to consolidate everything into a new will.
What To Gather Before You Draft
You will need your full legal name, your current address, and the exact date your original will was signed. That date links the codicil to the correct will, which matters if you have executed more than one over the years.
Pinpoint exactly what you are changing. Identify the article, section, or paragraph number in the original will that you want to amend, replace, or remove. If you are naming a new executor or adding a beneficiary, have that person’s full legal name ready. If you are changing a gift, describe the asset specifically or state the exact dollar amount. Vague references like “my jewelry” or “some of my savings” invite disputes. The more precise you are, the less room anyone has to argue about what you meant.
You also need testamentary capacity at the moment you sign, which is the same standard the will itself required: at least 18 years old, and of sound mind in the sense that you understand what a will does, have a reasonable sense of what you own, know who your natural heirs are, and grasp how the codicil changes the distribution of your estate. Capacity is measured at signing, not before or after. If there is any question about your mental state, having a physician confirm capacity close to the signing date creates a useful record.
Drafting the Codicil
Open with a statement that identifies the document as a codicil and ties it to your existing will. Something like: “I, [Full Legal Name], of [City, State], declare this to be the first codicil to my Last Will and Testament dated [Date].” If you have prior codicils, number this one accordingly.
The body states each change clearly. Reference the specific provision being modified and spell out the new language. For example: “I revoke Article III, Section 2 of my will and replace it with the following: [new text].” Or: “I add the following provision as a new Section 4 to Article V: [new text].” Each change should be its own numbered paragraph so there is no confusion about where one amendment ends and the next begins.
Close with a ratification clause confirming that every provision of the original will not specifically changed by this codicil remains in effect. That single sentence prevents anyone from arguing that the codicil was meant to undo parts of the will it never mentions. Then add a signature line for yourself, a date line, and signature lines for your witnesses.
Signing and Witnessing
A codicil must be executed with the same formalities your state requires for a will. Under the model followed by most states, the codicil must be in writing, signed by you, and signed by at least two witnesses who watched you sign or heard you acknowledge your signature. You sign first, then the witnesses sign. Most states require the witnesses to sign in your presence.
Who qualifies as a witness varies by state. Under the Uniform Probate Code, adopted in whole or in part by roughly 18 states, any person generally competent to be a witness may serve, and a will is not invalidated just because a witness is also a beneficiary. Other states still follow the older rule that witnesses should be “disinterested,” meaning they do not stand to inherit under the will or the codicil. Using disinterested witnesses is the safest approach regardless of where you live, because it removes one potential avenue for a legal challenge.
A handful of states also recognize holographic codicils, meaning ones written entirely in your own handwriting and signed by you, with no witnesses required. Not every state accepts these, and even where valid they are easier to contest than a properly witnessed codicil. If you go this route, every material word must be in your handwriting, not typed or printed.
Making the Codicil Self-Proving
A self-proving affidavit is optional but worthwhile. You and your witnesses sign a sworn statement before a notary public confirming that all the execution formalities were followed. The affidavit is attached to the codicil and, during probate, eliminates the need for the witnesses to appear in court to verify their signatures.
The affidavit typically states that you declared the document to be your codicil, that you signed it voluntarily, that the witnesses signed in your presence and in the presence of each other, and that you appeared to be of sound mind. The notary then signs and affixes their seal. This small step saves your executor real trouble later, especially if a witness has moved, become difficult to locate, or died by the time the will is probated. Most states authorize self-proving affidavits.
Storing the Codicil and Telling Your Executor
Keep the codicil physically attached to, or stored with, your original will. If the documents get separated, your executor might submit the will for probate without ever knowing the codicil exists, and the original terms would control. A fireproof safe at home, a safe deposit box, or your attorney’s office all work, as long as the codicil and will stay together.
Tell your executor the codicil exists and where to find it. This sounds obvious, but it is the step people skip most often. If you have named a backup executor, let that person know too.
Mistakes That Can Void a Codicil
Most codicil problems fall into a few predictable categories:
- Improper witnessing. Missing even one witness signature, or using witnesses who were not present when you signed, can void the entire codicil. Some states also void or reduce gifts to witnesses who are beneficiaries under the document.
- Ambiguous language. A codicil that conflicts with the original will without clearly stating which provision it replaces creates exactly the kind of confusion courts dread. Identify the specific section and state the replacement language in full.
- Failure to reference the will. A codicil that does not identify the original will by date and description may not be recognized as an amendment to it, especially if multiple wills exist.
- Lack of capacity or undue influence. If someone pressured you into the changes, or you did not fully understand what you were signing, the codicil is vulnerable to challenge. Each codicil is a separate signing event, and challengers can target one while leaving the rest of your estate plan intact.
- Detachment from the will. A codicil physically separated from the original will may never reach the probate court. Clip or staple it to the will, store them together, and make sure your executor knows both documents exist.
What It Costs
An estate planning attorney will generally draft a simple codicil for somewhere between $100 and $400. More complex changes or higher-cost markets push the price toward the upper end. Some attorneys charge a flat fee, others bill at their hourly rate. Either way, a codicil costs considerably less than drafting a new will from scratch, which is part of its appeal for small, isolated changes.
DIY codicil forms and templates are available online, sometimes for free. They can work for very simple changes, but the risk is missing a formality your state requires or drafting language that creates an unintended conflict with your existing will. Given that the stakes involve how your property passes after death, the cost of professional drafting is modest insurance against a much more expensive probate dispute.