Postnuptial Agreement UK – What It Covers, Legal Requirements, Enforceability and Template

Updated: February 2026 • Based on UK Law

This guide covers UK legal requirements, enforceability, costs, DIY options and how courts treat postnuptial agreements. Free postnuptial agreement checklist included.

A husband inherits £200,000 from his parents during the marriage. His wife’s business doubles in value over five years. Neither spouse discussed what would happen to those assets if the marriage ended.

When they divorce, the court treats everything as part of the shared “matrimonial pot” — including the inheritance and the business. Both spouses lose control of the outcome. Solicitor fees reach £25,000 each. The final settlement satisfies neither of them.

A postnuptial agreement could have resolved all of this in advance — for a fraction of the cost.

Without a postnuptial agreement, courts divide assets using broad discretion under the Matrimonial Causes Act 1973. The outcome is unpredictable and often expensive to litigate.

A well-drafted postnuptial agreement gives both spouses clarity and control over financial outcomes if the relationship breaks down.

This guide explains whether postnuptial agreements are legally binding, what courts look for when deciding enforceability, typical costs, and how to create one that carries real weight. For couples considering protection before marriage, see our prenuptial agreement guide.

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Is a Postnuptial Agreement Legal in the UK?

Yes — postnuptial agreements are legal in England and Wales. There is no law preventing married couples from entering into a contract about how their assets should be divided on divorce.

However, unlike contracts in commercial law, postnuptial agreements are not automatically binding on the courts.

What Changed After Radmacher v Granatino?

The legal position changed significantly following the Supreme Court decision in Radmacher v Granatino [2010] UKSC 42.

The court established that it should give effect to a nuptial agreement that is freely entered into by each party with a full appreciation of its implications — unless it would be unfair to hold the parties to the agreement.

This means postnuptial agreements are legal and courts will consider them seriously. But a judge retains ultimate discretion to depart from the agreement if following it would produce an unfair outcome.

Children’s needs and financial hardship are the two main reasons courts set aside agreements.

What Does This Mean in Practice?

A properly drafted postnuptial agreement carries significant weight and will usually be upheld.

A poorly drafted one may be given little or no weight. The difference often comes down to whether proper legal safeguards were followed when creating the agreement.

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Are Postnuptial Agreements Legally Binding in the UK?

No — postnuptial agreements are not automatically legally binding in England and Wales. The court always retains discretion to override a postnuptial agreement if upholding it would be unfair.

However, courts now give significant weight to properly executed agreements and will usually uphold them.

The key question is not “is it binding?” but “will the court uphold it?”

Following Radmacher, courts consider whether the agreement was freely entered into with full understanding — and whether it would be fair to hold the parties to it.

What Makes a Postnuptial Agreement More Likely to Be Upheld?

Courts consider several factors when deciding how much weight to give a postnuptial agreement:

• Full financial disclosure: Both spouses must provide complete disclosure of assets, income, debts and financial expectations. Hidden assets or incomplete disclosure can invalidate the entire agreement.
• Independent legal advice: Each spouse should receive separate legal advice from different solicitors. This demonstrates both parties understood what they were agreeing to and the rights they were giving up.
• No undue pressure or duress: The agreement must be entered into freely. If one spouse pressured the other or the agreement was signed during a crisis, courts may disregard it.
• Fair terms: The agreement should not leave one spouse significantly worse off than under standard divorce law — particularly if circumstances have changed since signing.
• Needs of children: Courts always prioritise children’s welfare. A postnuptial agreement cannot override the court’s duty to ensure children are properly provided for.
• Reasonable timing: Unlike prenuptial agreements (which should be signed at least 28 days before the wedding), postnuptial agreements can be signed at any time during marriage. However, agreements signed during a relationship crisis may face more scrutiny.

For complete guidance on financial disclosure requirements, see our divorce financial disclosure guide.

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How Much Does a Postnuptial Agreement Cost in the UK?

A postnuptial agreement typically costs between £1,000 and £5,000+ when using solicitors. London firms generally charge more than regional practices.

Each spouse needs their own solicitor for independent legal advice, so the total cost covers two sets of legal fees.

What’s the Cost Breakdown?

• Simple agreement (straightforward assets): £1,000–£2,000 total (both parties’ costs)
• Medium complexity (property, pensions, business interests): £2,000–£4,000 total
• High complexity (multiple properties, international assets, business valuations): £5,000–£15,000+ total

These costs typically include initial consultations, drafting, reviewing and negotiating terms, providing certificates of independent legal advice, and execution.

DIY vs Solicitor Costs

A DIY postnuptial agreement using a professionally drafted template costs from £10. However, even with a template, courts place significant weight on whether both parties received independent legal advice.

A middle-ground approach: use a template for drafting, then have solicitors review and certify the final document. This can reduce costs to £500–£1,000 total while still providing the independent advice that strengthens enforceability.

The key consideration is proportionality. For a couple with modest assets (under £100,000), spending £5,000 on legal fees may not be sensible. For substantial assets or complex business interests, professional drafting is recommended.

If you have children and need to address custody arrangements separately, see our child arrangement agreement guide.

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How to Get a Postnuptial Agreement in the UK

Getting a postnuptial agreement involves several key steps — whether you use solicitors throughout or take a hybrid approach with templates and legal review.

Step 1: Full Financial Disclosure

Both spouses must provide complete disclosure of their financial position. This includes:

• All assets (property, savings, investments, pensions, business interests)
• All debts (mortgages, loans, credit cards)
• Current income and expected future income
• Any inheritances or gifts expected

Use our free postnuptial agreement checklist to ensure nothing is missed.

Step 2: Agree the Key Terms

Discuss and agree what the postnuptial agreement will cover: how property will be divided, treatment of pre-marital assets, division of assets acquired during marriage, pension sharing, spousal maintenance provisions, and what happens to the family home.

Step 3: Draft the Agreement

Either instruct a solicitor to draft from scratch, or use a professionally drafted template and customise it to your circumstances.

The agreement must be clear, comprehensive and reflect what both parties have agreed.

Step 4: Independent Legal Advice

Each spouse should receive independent legal advice from separate solicitors. This is not legally required — but courts give significantly more weight to agreements where both parties had independent advice.

The solicitors should provide certificates confirming they explained the agreement and its implications.

Step 5: Execute the Agreement

Both spouses sign the agreement in the presence of witnesses. The witnesses should be independent adults who are not family members.

Keep the original safely stored and ensure both parties have copies.

Step 6: Review Periodically

Life circumstances change. Review the postnuptial agreement after major life events: birth of children, significant inheritance, career changes, property purchases, or substantial changes in either spouse’s financial position.

Updating the agreement maintains its relevance and enforceability.

If your relationship has already broken down, see our separation agreement guide instead.

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Can You Make a DIY Postnuptial Agreement in the UK?

Yes — there is no legal requirement to use a solicitor to create a postnuptial agreement. A DIY postnuptial agreement using a professionally drafted template is valid.

However, the question is whether a court will give it significant weight if challenged on divorce.

When Does DIY Work Well?

A DIY approach can work well when:

• Both spouses have straightforward finances with modest assets
• Both parties fully understand what they’re agreeing to
• There is genuine mutual agreement with no pressure from either side
• Both parties are willing to make full financial disclosure

When Should You Get Professional Help?

Professional drafting is strongly recommended when:

• There are substantial assets (property, pensions, businesses)
• One spouse has significantly more wealth than the other
• There are international assets or complex ownership structures
• Either spouse has been married before
• There’s any hint of disagreement or pressure

The Hybrid Approach

Many couples take a middle path: use a professionally drafted template to create the initial agreement, then have solicitors review it and provide independent legal advice certificates.

This combines cost savings with the enforceability benefits of legal involvement.

Important: even a DIY agreement must include proper financial disclosure schedules. Without evidence that both parties knew what the other had, courts may give the agreement little weight.

For couples who are not married but living together, a cohabitation agreement provides similar protection.

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What Are the Disadvantages of a Postnuptial Agreement?

While postnuptial agreements offer significant benefits, there are genuine disadvantages to consider.

Not Automatically Binding

Unlike commercial contracts, postnuptial agreements can be overridden by a court if upholding them would be unfair.

You cannot guarantee the agreement will be followed exactly as written — particularly if circumstances change significantly.

Can Create Relationship Tension

Asking a spouse to sign a postnuptial agreement can create conflict. It may feel like planning for divorce.

The negotiation process can surface disagreements about money and fairness that were previously unspoken.

Cost of Proper Execution

Both spouses need independent legal advice to maximise enforceability. This means paying for two solicitors — £1,000–£5,000+ depending on complexity.

For couples with modest assets, this cost may outweigh the benefits.

May Become Outdated

Life circumstances change — children are born, careers progress, inheritances arrive, property values shift.

A postnuptial agreement that was fair when signed may become unfair years later. Courts can depart from outdated agreements, particularly where one spouse’s needs have increased.

Cannot Override Children’s Needs

Courts always prioritise children’s welfare over any agreement between parents. See the next section for specific exclusions.

False Sense of Security

Some people believe a postnuptial agreement guarantees a specific outcome on divorce. It doesn’t.

While courts give significant weight to properly executed agreements, they retain discretion. Relying entirely on an agreement without understanding its limitations can lead to disappointment.

If your marriage has already broken down, a financial settlement agreement as part of divorce proceedings may be more appropriate.

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What Cannot Be Included in a Postnuptial Agreement?

Postnuptial agreements can cover most financial matters, but there are clear limits — and courts will ignore or strike out provisions that cross these lines.

Child Arrangements and Custody

A postnuptial agreement cannot determine child custody, living arrangements or contact schedules.

Courts always retain jurisdiction over children’s welfare and will make decisions based on the child’s best interests at the time — not based on what parents agreed years earlier.

For child-related matters, see our parenting plan guide.

Child Maintenance

You cannot contract out of child maintenance obligations. The Child Maintenance Service (CMS) can make assessments regardless of what any agreement says.

While you can include provisions about private school fees or additional support, the basic maintenance obligation cannot be waived or capped by agreement.

Provisions That Would Leave a Spouse Destitute

Courts will not uphold provisions that would leave one spouse unable to meet their basic needs.

An agreement that gives one spouse everything while the other gets nothing will be overridden — particularly if that spouse has been out of work raising children or has health issues limiting their earning capacity.

Illegal or Punitive Terms

Any provision requiring illegal activity, or terms a court considers contrary to public policy, will be unenforceable.

This includes provisions that penalise a spouse for “fault” in ways the court considers punitive rather than fair.

Future Inheritance Before Received

While you can address how actual inheritances will be treated, you cannot bind someone to deal with an expected inheritance in a particular way before they’ve received it.

The inheritance may never materialise — or may come with its own conditions.

Waiving Pension Rights Entirely

Pensions are often the largest marital asset after property. While postnuptial agreements can address how pensions will be divided, provisions that entirely exclude one spouse from any pension sharing may not be upheld.

This is particularly the case if that spouse would otherwise be left without adequate retirement provision.

If you own property jointly and want to record ownership shares separately, see our declaration of trust guide.

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Frequently Asked Questions: Postnuptial Agreements UK

What is the difference between a prenuptial and postnuptial agreement?

The only difference is timing. A prenuptial agreement is signed before marriage; a postnuptial agreement is signed after.

Both serve the same purpose — setting out how assets will be divided if the marriage ends. Courts treat them similarly in terms of enforceability.

Can I get a postnuptial agreement if I didn’t get a prenup?

Yes — this is one of the main reasons people get postnuptial agreements. Many couples don’t think about asset protection before marriage, or circumstances change afterwards.

A postnuptial agreement can achieve everything a prenup would have.

How long does a postnuptial agreement last?

A postnuptial agreement remains in effect until divorce, annulment, or until both parties agree to revoke or replace it. There is no automatic expiry date.

However, the longer the gap between signing and divorce, the more likely circumstances will have changed — and courts may give less weight to outdated agreements.

Can a postnuptial agreement be challenged?

Yes — either spouse can ask the court to depart from the agreement on divorce. Common grounds for challenge include inadequate financial disclosure, no independent legal advice, one party was under pressure, terms have become unfair due to changed circumstances, or the agreement doesn’t adequately provide for children’s needs.

Do both parties need a solicitor?

It’s not legally required, but strongly recommended. Courts place significant weight on whether both parties received independent legal advice.

If only one spouse had advice — or neither did — the court may question whether the agreement was truly understood and freely entered into.

Can we do a postnuptial agreement ourselves?

Yes — there’s no legal requirement to use solicitors. To maximise enforceability, use a professionally drafted template, make full financial disclosure, ensure both parties understand exactly what they’re agreeing to, and consider having the agreement reviewed by solicitors.

What if my spouse won’t sign a postnuptial agreement?

You cannot force a spouse to sign. If they refuse, options include: continuing discussions to understand their concerns, suggesting mediation to reach compromise, or consulting a solicitor about your position without an agreement.

Pressuring or threatening a spouse to sign would undermine the agreement’s enforceability anyway.

Can a postnuptial agreement protect my business?

Yes — business protection is one of the most common reasons for postnuptial agreements. The agreement can specify that the business remains with the owning spouse, set out how business value will be calculated, and determine whether growth during marriage is shared.

However, if the business is the main family asset, courts may still award some share to meet the other spouse’s needs.

Does a postnuptial agreement cover debts?

Yes — postnuptial agreements can address how debts will be allocated on divorce. This includes mortgages, loans, credit cards and business debts.

However, this only binds the spouses — it doesn’t prevent creditors from pursuing either party for joint debts.

Can I change a postnuptial agreement after signing?

Yes — postnuptial agreements can be varied or replaced by mutual agreement. If circumstances change significantly, it’s sensible to review and update the agreement.

The new agreement should be executed with the same formalities as the original.

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Official Sources

• Matrimonial Causes Act 1973, Section 25 — Matters to which court is to have regard
• Radmacher v Granatino [2010] UKSC 42 — Supreme Court Judgment
• Law Commission — Matrimonial Property, Needs and Agreements
• GOV.UK — Making Child Arrangements

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The Truth About “Free” Legal Template Sites (What You’re Really Signing Up For)

Most websites offering a “free legal template” follow the same pattern:

• You click because it’s advertised as free
• You spend 10–15 minutes answering questions
• At the very end, you must create an account or start a “free trial”
• Your card is required upfront
• The subscription auto-renews at £29–£39 per month

This isn’t a free template — it’s a subscription service. Many people only realise after being charged £300–£400 over the year.

Why These “Free” Templates Are a Legal Risk

• Outdated wording: not aligned with current UK law
• Missing mandatory clauses: required for legal validity
• No compliance guidance: leaving users without legal context
• No structured checklist: no way to verify the document works
• Not kept updated: often unchanged when legislation changes

One incorrect clause can weaken or invalidate the entire document.

Hidden Problem: Many “Free Template” Sites Aren’t Even UK-Based

Another major issue is that many free or auto-subscription template sites operate outside the UK and use documents originally drafted for the US legal system. These are then loosely adapted for “international use,” which creates serious problems:

• Incorrect terminology: taken from US contract law
• Missing UK statutory references: essential legal requirements omitted
• Non-applicable clauses: terms that don’t apply under UK legislation
• Legal conflicts: risks breaching UK consumer, employment, or GDPR rules

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Related Guides

• Prenuptial Agreement Guide UK
• Cohabitation Agreement Guide UK
• Separation Agreement Guide UK
• Financial Settlement Agreement Guide UK

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Last updated: February 2026

Disclaimer: This guide provides general UK legal information, not legal advice. Laws are current as of February 2026.