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What is a Codicil? (And Should You Use One?)

· 11 min

Michael thought adding a codicil would be simple. At 62, he wanted to add his new grandson, Leo, as a beneficiary in his will—a straightforward change, he thought. He downloaded a codicil template online, filled it in, and had two neighbours witness it.

Three years later, when Michael died, his executors discovered the codicil contradicted an earlier clause about residuary estate distribution. The family spent £8,400 in legal fees resolving the ambiguity, and Leo's inheritance was delayed by 14 months. A new will would have cost Michael £150.

Michael's situation isn't unusual. Recent statistics show that 59% of parents don't have a will or have one that's out of date, and when they do update them, many reach for codicils as the "quick fix." But codicils—legal documents that amend existing wills—come with hidden risks that most people don't discover until it's too late.

This guide explains exactly what codicils are, when they work, when they fail catastrophically, and why writing a fresh will is often the safer (and surprisingly affordable) choice.

Table of Contents

A codicil is a supplementary legal document that amends, adds to, or revokes specific provisions in an existing will while leaving the rest of the will intact. Think of it as a formal amendment rather than a complete rewrite.

Codicils originated in an era when will-writing was expensive and time-consuming. In the typewriter era, making a change meant retyping the entire document. A codicil offered a practical shortcut—you could add a single page rather than starting from scratch.

But here's what many people miss: a codicil must be executed with exactly the same legal formalities as a will under the Wills Act 1837. This means:

  • The testator (person making the codicil) must sign it
  • Two independent witnesses must watch the signing and sign themselves
  • Witnesses must be over 18 in England and Wales (16 in Scotland)
  • Witnesses cannot be beneficiaries, executors, or their spouses

Once properly executed and stored with the original will, a codicil becomes legally binding. The critical difference between a codicil and a new will is scope: codicils supplement an existing will, while new wills completely replace all previous wills and codicils.

This isn't an informal note or letter. A codicil is a formal legal document that requires careful drafting, proper execution, and safe storage alongside your original will.

When Codicils Work (The Very Limited Use Cases)

Codicils can work perfectly well, but only in very specific, narrowly defined situations. Legal guidance suggests codicils are appropriate only when changes affect less than 10% of your estate value.

Here are the genuinely appropriate use cases:

Minor administrative updates:

Changing an executor's or guardian's name due to marriage. Updating a beneficiary's address for contact purposes. These are simple name or contact detail changes that don't affect distribution.

Small monetary adjustments:

Increasing a specific legacy from £5,000 to £10,000, provided this doesn't affect other provisions or percentages in your will. The change must stand alone without ripple effects.

Adding a small charitable gift:

Including a £500 donation to a new charity you want to support. The key is "small"—a minor addition that doesn't alter the main estate distribution.

Replacing a single item-specific gift:

Your 2020 will left "my Ford Fiesta" to your nephew. You've since traded it for a Honda Civic. A codicil can simply replace "Ford Fiesta" with "Honda Civic" without touching anything else.

David's situation demonstrates this narrow sweet spot. His 2020 will named his sister as executor. When she moved to Australia in 2024, he used a codicil to replace her with his brother-in-law. Cost: £60. Time: one week. No complications because it was truly a single, isolated change.

But here's the crucial caveat: even these "minor" changes can cause problems if they interact with other will clauses in unexpected ways. A seemingly simple update to one beneficiary might create unintended consequences for residuary estate distribution or trust provisions.

If you have any doubt about whether your change is isolated and simple, that doubt is your answer—you need a new will.

When Codicils Fail (The Real Risks Nobody Tells You)

Most articles about codicils gloss over the risks. We won't. Understanding the specific failure modes helps you make an informed decision.

Risk 1: Contradictions and ambiguity.

This is exactly what happened to Michael in our opening example. His codicil added Leo as a beneficiary for £20,000, but the wording conflicted with the residuary clause that said "all remaining estate to be divided equally among my children." Did Leo's £20,000 come before or after the residuary division? The ambiguity cost the family £8,400 in legal fees and 14 months of delays.

Risk 2: Lost or separated documents.

Codicils stored separately from the original will create chaos. Executors might find the will but not the codicil, or vice versa. Contested probate cases rose to 122 in 2023, with document loss being a contributing factor in many disputes.

Risk 3: Multiple codicils creating chaos.

Sarah wrote a codicil in 2018 changing her executor. Another in 2020 updating a legacy. A third in 2023 adding a charity. Each referred to "my will dated 15 March 2015." Her executors had to read and reconcile four separate documents. The legal complexity cost her estate £5,200 in additional probate fees.

Risk 4: Unintended revocation.

Poorly worded codicils can accidentally revoke more of the original will than you intended. If your codicil says "I revoke clause 5" but clause 5 contains multiple provisions, you might unintentionally revoke provisions you wanted to keep.

Risk 5: Missing legislative updates.

Your original will from 2010 doesn't reflect 2024 intestacy rules where the statutory legacy increased to £322,000. A codicil doesn't fix these underlying issues—it just patches an outdated document.

Risk 6: Physical attachment invalidation.

Some people staple or paperclip their codicil to their will, thinking they're being organized. But physical attachment can actually raise questions about whether the original will has been tampered with, potentially invalidating it under Wills Act requirements.

These aren't theoretical risks. They're real problems that solicitors encounter regularly when administering estates with codicils. The cost to families ranges from £3,000 to £15,000 in legal fees to resolve codicil-related complications.

Codicil vs New Will (The Honest Comparison)

The question isn't whether codicils are ever appropriate—it's whether they make sense for your specific situation in 2025. Here's the honest comparison:

Criteria Codicil New Will
Cost £20-150 (DIY to solicitor) £99.99 (WUHLD) to £650 (solicitor)
Time required 1-2 weeks with solicitor 15 minutes online (WUHLD) to 4-6 weeks (solicitor)
Legal risk Moderate to high (ambiguity, contradiction) Low (clean slate, no confusion)
Clarity for executors Must read 2+ documents Single clear document
Storage complexity Must keep documents together forever One document only
Future updates Requires additional codicils (compounds risk) Full rewrite anytime
Reflects current law No (works with outdated will) Yes (fresh document reflects 2024 law)

The legal consensus is clear. As multiple UK solicitor firms advise, "in the immense majority of cases it is advisable to make a new will instead of a codicil."

Here's the cost-benefit reality: Even if a solicitor charges £150 for a new will versus £60 for a codicil, the £90 difference is minimal compared to the thousands your family might spend resolving codicil complications. The risk reduction is worth it.

And with WUHLD at £99.99 with preview functionality, the cost argument for codicils essentially evaporates. You get a complete, fresh will—with no contradiction risk—for barely more than what many solicitors charge for a codicil.

How to Write a Codicil (If You Absolutely Must)

Important:

This guidance is for informational purposes. If you're drafting a codicil, we strongly recommend professional legal review, even for seemingly simple changes. Errors in codicil language can create expensive probate complications.

If you've determined that a codicil is truly appropriate for your situation, here's how to minimize risk:

Step 1: Draft the codicil language carefully. Use this structure:

"I, [your full name] of [your full address], declare this to be a codicil to my will dated [exact date of original will].

I make the following change: [state the specific change clearly, e.g., "I revoke clause 5 and replace it with: I leave £10,000 to my nephew James Smith of 123 Oak Street, London."]

In all other respects I confirm my will dated [exact date]."

Be extremely specific. Use the exact clause numbers from your original will. State clearly what you're revoking, replacing, or adding.

Step 2: Ensure proper execution.

  • You must sign the codicil in ink
  • Two independent witnesses must watch you sign
  • Witnesses cannot be beneficiaries, executors, or married to beneficiaries or executors
  • Both witnesses must be present simultaneously when you sign
  • Witnesses then sign in your presence (they don't need to read the codicil)

This is exactly the same as the legal requirements for UK wills. There are no shortcuts.

Step 3: Date clearly. The date is crucial. If there's ever a conflict between documents, the most recent dated document generally prevails. Use a full date: day, month, year.

Step 4: Store correctly. Keep your codicil with your original will in the same location. Never physically attach them with staples, paperclips, or pins—this can raise questions about document tampering.

Tell your executor explicitly that both documents exist and exactly where they're stored. Consider registering both with the National Will Register.

Step 5: Review with a solicitor. Even if you've drafted the codicil yourself, have a solicitor review it before execution. A one-hour review (typically £100-150) can catch contradictions you didn't see.

Critical warning:

If your change affects more than one clause, involves percentages of your estate, changes residuary beneficiaries, or if you're unsure whether it creates contradictions—STOP. Write a new will instead.

Codicil risks are often invisible to non-lawyers. What seems straightforward may interact with other will provisions in unexpected ways.

How Much Does a Codicil Cost?

Understanding the true cost means looking beyond the initial price tag to include potential downstream costs.

Solicitor codicil costs

range from £40 to £150, depending on complexity. Specific examples from 2024:

Legal review adds another £20-40 if you draft it yourself and want professional checking.

Online template services

charge £20-70. Legalo's codicil template costs £19.95. But here's the risk: no legal review means it's easy to make mistakes. If your codicil causes probate issues, families typically spend £3,000-15,000 resolving them—far more than the £20 you "saved."

DIY free templates

cost £0 but carry the highest risk. Without guidance on proper wording, witnessing, or storage, the chance of errors is significant.

New will costs for comparison:

  • Solicitor new will: £150-650 for a single will
  • WUHLD: £99.99 (single will with preview, unlimited pre-payment edits)
  • Which? Wills: £39-59 codicil vs £90+ new will
  • Farewill: £20-80 codicil vs £90 + £10/year subscription

The cost-benefit conclusion:

If a new will costs only £50-100 more than a codicil, the risk reduction makes it worth it. With WUHLD at £99.99—barely more than most solicitor codicils—there's virtually no cost advantage to choosing a codicil.

You're essentially choosing between:

  • Option A: £60-80 codicil with moderate to high legal risk
  • Option B: £99.99 new will with low legal risk, preview functionality, and peace of mind

The math is clear.

Life Events That Require More Than a Codicil

Certain life changes are simply too significant for codicils. Here's when you definitely need a new will, not a codicil:

You got married or entered a civil partnership.

Marriage automatically revokes any previous will under UK law. You must write a completely new will. A codicil cannot fix this—your previous will is void the moment you marry.

You got divorced or dissolved your civil partnership.

Divorce partially revokes will provisions relating to your ex-spouse, but creates legal ambiguity. Write a fresh will that clearly reflects your new wishes.

You had a child or grandchild you want to include as a beneficiary.

Adding a child isn't just about listing their name. It involves guardianship provisions, trust arrangements, and adjusting residuary estate distribution. These interconnected changes are far too complex for a codicil.

A named executor or main beneficiary has died.

This affects the fundamental structure of your will, not just a minor detail. You need to reconsider your entire estate plan.

You want to change your residuary estate distribution.

The residuary estate (everything not specifically gifted) is the backbone of most wills. Changing who gets "everything else" requires a new will, not a patch.

You acquired significant new assets.

Bought a second property? Started a business? Inherited investments? If new assets represent more than 10% of your estate value, you need a new will that addresses them properly.

Your circumstances changed significantly.

Remarriage, blended families, or estrangement from family members all require careful rewording of your entire will. A codicil can't handle this complexity.

Your existing will is more than 5 years old.

UK law evolves. Intestacy rules change. Your old will might not reflect current legal requirements or your current situation. Understanding when to update your will helps you avoid outdated provisions.

Consider these specific scenarios:

Emma, 38, got divorced and remarried with stepchildren. She needs a new will to address her blended family structure, not a codicil to her pre-divorce will.

James, 45, bought a rental property worth £280,000. This major asset addition means his 2019 will no longer accurately reflects his estate. He needs a fresh will.

Sarah, 52, wants to replace her executor who moved abroad. This might work with a codicil, but a new will is safer and barely more expensive.

The common thread: if your life has changed in any meaningful way, you need more than a codicil can provide.

Why Writing a New Will is Easier (and Safer) Than You Think

The main reason people consider codicils is based on outdated assumptions about will-writing. Let's dispel those myths:

Myth 1: "New wills take weeks." Reality: With WUHLD, you can create a complete, legally valid will in 15 minutes online. No appointments. No waiting for solicitor availability. You can do it from your sofa tonight.

Traditional solicitor wills do take 4-6 weeks, but online services have eliminated that barrier entirely.

Myth 2: "New wills cost £500+." Reality: £99.99 for WUHLD. That's barely more than the £60-80 most solicitors charge for a codicil, and far less than the £150-650 solicitors charge for new wills. Learn more about will costs to see the full picture.

Myth 3: "I'll lose my previous good clauses." Reality: You can replicate any provisions you want to keep while improving or updating outdated sections. Think of it as an opportunity to review everything with fresh eyes, ensuring your entire will reflects your current wishes and current law.

Myth 4: "I need multiple solicitor meetings." Reality: Modern online services guide you step-by-step through every question. WUHLD's platform explains each section clearly, helps you make informed decisions, and ensures you haven't missed anything important.

The benefits of a fresh will over a codicil are substantial: A clean slate eliminates all contradiction risk. There's no possibility of conflicting clauses because you're starting fresh.

Your new will reflects current UK law, including the 2024 intestacy rules, current statutory legacy amounts, and any other legal changes since your old will was written.

Executors deal with a single clear document. They don't need to read multiple documents, reconcile changes, or wonder if they've found all the codicils.

Storage is simpler—one document to keep safe, not multiple documents that must stay together forever.

No compounding complexity from multiple amendments. Every future update starts with a complete will, not a will plus codicils.

Peace of mind that everything is current, correct, and clear for your family.

WUHLD makes this simple: £99.99 one-time payment—no subscriptions, no recurring fees, no hidden costs.

15 minutes online from start to finish. Answer straightforward questions about your family, assets, and wishes.

Preview your will FREE before paying. See exactly what you're getting. No credit card required to preview. Only pay when you're completely satisfied.

Four documents included: your will, plus a 12-page Testator Guide explaining how to execute it properly, a Witness Guide to give to your witnesses, and a Complete Asset Inventory document.

Unlimited edits before you pay. Change your mind about a beneficiary? Adjust an amount? No problem—edit as many times as you want while previewing.

Legally valid in England and Wales under the Wills Act 1837.

Suitable for straightforward estates: couples, children, property, savings, pensions. If you have complex trusts, international property, or business succession needs, you may need specialist legal advice. But for most people, WUHLD covers everything you need.

The bottom line: the traditional reasons for choosing codicils—cost and time—no longer apply in 2025. Modern online will services offer the safety of a fresh will with the convenience and affordability people thought codicils provided.

What to Do If You Already Have a Codicil

If you have an existing codicil, don't panic. But do assess your risk level and take appropriate action.

Assess your risk level: Low risk:

You have a single codicil that made one minor change (like changing an executor), the language is clear, it's stored with your will, and you haven't had major life changes since.

Medium risk:

You have multiple codicils, OR your codicil is older than 5 years, OR your original will dates from before 2020 and may not reflect current law.

High risk:

Your codicil language is ambiguous, potentially contradicts will clauses, is stored separately from your will, OR you've had major life changes (marriage, divorce, children, significant asset changes) since the codicil was created.

Action steps by risk level: For low risk:

Ensure your codicil is stored with your will in a safe location. Tell your executor exactly where both documents are. Consider consolidating into a new will at your next life event—not because there's a problem now, but as a preventive measure.

For medium risk:

Have a solicitor review your will and codicil for potential contradictions and ambiguity. This review typically costs £100-150 and could reveal issues you didn't know existed. Strongly consider writing a new will now rather than waiting.

For high risk:

Write a new will immediately. Don't wait for the next life event. The complications your codicil could cause during probate far outweigh the cost of a new will.

How to revoke a codicil: Physical destruction: Tear up or burn the codicil with clear intent to revoke it. This must be your intentional act of revocation.

Written revocation: Create a written revocation document executed with the same formalities (signed, witnessed by two independent adults). This formally states: "I revoke my codicil dated [date]."

Write a new will: This automatically revokes all previous wills and codicils. It's the cleanest method because it ensures no confusion about what's valid.

Timeline consideration:

If your codicil dates from before 2020, significant time has passed. UK law may have changed. Your life has likely changed. Your asset values have certainly changed. A new will is strongly recommended.

Executor communication:

If you're keeping your codicil, tell your executor explicitly:

"I have a will dated [date] and a codicil dated [date]. Both documents are stored together at [location]. Both must be read together to understand my final wishes."

This clear communication prevents the scenario where an executor finds one document but not the other.

The goal isn't to create anxiety about existing codicils. Many work perfectly well. But an honest assessment of your situation helps you determine whether yours is one of them—or whether it's time to eliminate the risk entirely with a fresh will.

Frequently Asked Questions

Can I write a codicil without a solicitor?

Yes, legally you can, but it's high risk. Codicils must follow exact Wills Act 1837 formalities (signed by you, witnessed by two independent adults). Most DIY codicils contain errors that cause probate complications. If your change is simple enough for DIY, a new will through WUHLD (£99.99) is safer and barely more expensive than having a codicil reviewed by a solicitor.

How many codicils can you have on one will?

Legally, there's no limit. Practically, more than one codicil creates serious risk. Each additional codicil compounds ambiguity and contradiction risk. Solicitors strongly advise writing a new will if you need a second codicil. The complexity of reconciling multiple amendments vastly outweighs any perceived cost savings.

Does a codicil need to be witnessed?

Yes, absolutely. A codicil requires exactly the same formalities as a will: signed by you and witnessed by two independent adults over 18 (England/Wales) or 16 (Scotland). Witnesses cannot be beneficiaries, executors, or their spouses. Without proper witnessing, the codicil is legally invalid and won't be recognized during probate.

Will a codicil make my will invalid?

A properly executed codicil won't invalidate your will, but a poorly worded one can unintentionally revoke provisions you wanted to keep. The bigger risk is contradiction—if codicil language conflicts with original will clauses, it creates ambiguity that may require court resolution. This is why solicitors recommend new wills over codicils for most changes. The cost of resolving ambiguities far exceeds the cost of writing a fresh will.

How much does it cost to add a codicil vs write a new will?

Solicitor codicils cost £40-150, online templates £20-70. New wills cost £150-650 from solicitors, or £99.99 from WUHLD. If a new will costs £50-100 more than a codicil, the risk reduction is worth it—especially since codicil errors can cost families £3,000-15,000 in legal fees to resolve during probate.

What happens if my codicil contradicts my will?

Courts use legal construction rules to interpret your intent, but the process is expensive and time-consuming. If the contradiction is irreconcilable, later provisions generally prevail, but executors may need legal advice at your estate's expense (£3,000-8,000+). Families may dispute the interpretation, leading to probate litigation. This is the most common codicil failure mode and the primary reason legal professionals recommend new wills.

The Smart Choice: A Fresh Will for Modern Times

A codicil might seem like the convenient option—a quick patch to update your will without starting over. But as we've seen, the risks are real and the cost savings are minimal.

Key takeaways:

  • Codicils carry inherent risks of ambiguity, contradiction, and loss—even when properly executed
  • Legal professionals consistently recommend new wills over codicils in the majority of cases
  • The cost difference between a codicil (£40-150) and a new will (£99.99 with WUHLD) is minimal compared to the risk difference (£0 vs £3,000-15,000 in potential family legal fees)
  • Major life events (marriage, divorce, children, significant assets) always require new wills, not codicils
  • Modern online will services have eliminated the time and cost barriers that once made codicils attractive

The legal requirements for codicils haven't changed since 1837. But the practical case for using them has evaporated. Why risk ambiguity, contradiction, and family disputes when you can create a complete, clear, legally valid will in 15 minutes for £99.99?

Your family will be reading your will during an emotionally difficult time. Give them a single, clear document that leaves no room for confusion, contradiction, or costly legal interpretation.

Create your legally valid will today with WUHLD. Our step-by-step platform ensures you meet all UK legal requirements while avoiding the risks that come with codicils.

For just £99.99 (vs £650+ for a solicitor), you'll get:

  • Your complete, legally binding will
  • A 12-page Testator Guide explaining how to execute your will properly
  • A Witness Guide to give to your witnesses
  • A Complete Asset Inventory document

You can preview your entire will free before paying anything—no credit card required. See exactly what you're getting, make unlimited edits, and only pay when you're completely satisfied.

Preview Your Will Free – No Payment Required

Legal Disclaimer

This article provides general information about codicils and UK wills and does not constitute legal advice. For advice specific to your individual situation, please consult a qualified solicitor. WUHLD's online will service is suitable for straightforward UK estates; complex situations involving business succession, international property, or intricate trusts may require professional legal advice.

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