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What Is a Prenuptial Agreement?

A prenuptial agreement — also called an ante-nuptial agreement — is a legal document made by two people before they marry, setting out how specific assets, property, savings, businesses or other financial matters should be treated in the event of divorce or separation. The agreement is signed before the wedding takes place.

You may also hear the term postnuptial agreement, which is the same legal instrument made after the marriage has already taken place. Courts in England and Wales treat postnuptial agreements with broadly the same seriousness as prenuptial agreements, applying the same legal tests.

Many people misunderstand prenuptial agreements as pessimistic — a sign of doubt about the marriage. In reality, making a prenup is a form of financial planning, similar to making a will or taking out insurance. Most couples who make prenups never use them. The real value is in the clarity and protection they provide, and in the honest financial conversations they prompt before marriage.

A prenuptial agreement typically sets out:

• Which assets each party owns before the marriage (and wishes to keep separate)
• How property and savings acquired during the marriage will be treated
• What happens to business interests or shareholdings
• How pensions and retirement savings are treated
• Provisions for children (where relevant)
• What happens to inheritances or gifts during the marriage

A prenup does not address parental responsibility for children — that is determined separately under family law and cannot be contracted away.

Are Prenups Legally Binding in the UK?

In England and Wales, there is no statute that makes prenups automatically binding, unlike some other jurisdictions such as Scotland or most of continental Europe. However, the landmark Supreme Court case Radmacher v Granatino [2010] UKSC 42 fundamentally changed the landscape in 2010.

In that case, the Supreme Court held that a prenuptial agreement should be given effect unless it would be unfair to hold the parties to it at the time of enforcement. This is a powerful position: rather than being merely one factor in the court's discretion, a properly made prenup becomes the presumptive starting point.

The key test established by the Court was whether:

1. The agreement was freely entered into by both parties
2. Both parties had full appreciation of its implications
3. It is not unfair to hold them to it at the time of enforcement

The phrase "not automatically legally binding" is the correct legal description for prenups in England and Wales. Courts do not treat them as contracts in the strict commercial sense. Instead, they are given very significant weight — but always subject to the overriding principle that a court will not enforce an agreement if doing so would be unfair to either party, particularly where children are involved or one party's needs cannot be met.

This is why the process of making a prenup matters as much as the document itself. A prenup made carefully, with both parties receiving independent legal advice and full financial disclosure, will carry much more weight than one made hastily or with pressure.

The Four Criteria for Maximum Court Weight

To maximize the likelihood that a court will uphold a prenuptial agreement in England and Wales, both parties should ensure the agreement meets these four key criteria:

1. 1
   Independent Legal Advice for Both Parties

   Each partner must instruct their own separate solicitor. One solicitor cannot represent both parties — this is a fundamental requirement. Each solicitor's role is to advise their client on the meaning and implications of the agreement, and to certify that they have given that advice. This dual representation is not a procedural technicality; it demonstrates to the court that each party understood what they were agreeing to, and that neither was pressured by the other. The solicitor does not need to approve or disapprove of the terms — only to ensure their client understands them.

2. 2
   Full and Frank Financial Disclosure

   Both parties must disclose their complete financial picture to each other. This includes property, savings, investments, pensions, business interests, debts, and likely inheritances. Courts expect this disclosure to be thorough and honest. Concealment of significant assets may cause a court to disregard the agreement entirely, or at minimum to review it much more critically. Both solicitors typically request detailed financial statements from their clients and from the other party to ensure full disclosure has taken place. This is documented, and the exchange of disclosure forms the evidence trail the court will examine.

3. 3
   Signed at Least 28 Days Before the Wedding

   The agreement should be signed at least 28 days before the wedding takes place. Signing too close to the wedding date risks a later challenge on grounds of duress — that one party felt pressured into signing at the last moment. While 28 days is the accepted minimum, many specialists recommend signing 6–8 weeks before the wedding to provide a stronger buffer and to demonstrate that the agreement was made thoughtfully, not under time pressure. Courts understand that weddings create pressure, and they will scrutinize agreements signed days or weeks before the ceremony.

4. 4
   Terms Not Unconscionable at Enforcement

   Courts assess the fairness of a prenup at the time of application for divorce or separation, not at the time of signing. An agreement that seemed reasonable at the outset — when both parties were young, healthy, and earning similar amounts — may be challenged if circumstances have changed dramatically by the time of divorce. In particular, courts will be protective of children's needs and of either party being left destitute or unable to meet basic requirements. A prenup that leaves one party unable to house themselves or care for dependent children may not be upheld, even if it meets all three prior criteria perfectly.

Who Should Consider a Prenuptial Agreement?

A common misconception is that prenups are only for wealthy people or celebrities. In fact, a prenup can be valuable for any couple who has specific assets they wish to protect or ring-fence, regardless of total net worth. The question to ask is: "Are there assets I own that I specifically wish to remain mine, or to be treated differently if the relationship ends?" If the answer is yes, a prenup may be worth exploring.

The decision to make a prenup is a personal one. Some couples prefer the approach; others do not. But there is no wealth threshold that makes one person a "prenup person" and another not. It is about your specific circumstances, your assets, and your peace of mind.

How Much Does a Prenup Cost?

The cost of a prenup comprises two main elements: the drafting and advice fees from both solicitors, and any cost associated with the agreement itself (whether bespoke or template-based).

Both partners need separate solicitors — this is a legal requirement to meet the Radmacher v Granatino [2010] UKSC 42 criteria. Each solicitor charges for their work advising their own client. The true total cost is therefore the sum of both solicitors' fees.

For a straightforward case — two people with simple assets, no children, and no major negotiations — the typical cost is £2,500–£4,500 ex-VAT for both parties combined. This rises to £6,000–£10,000 for cases involving a business, overseas assets, or significant negotiation between the two solicitors. Cases involving high net worth assets, complex family structures, or international elements may cost £10,000–£15,000 or more.

It is important to understand that the advertised cost from any service is almost always per party, not the total. If a solicitor advertises £1,500 for a prenup, that is typically £1,500 per person — making the total for both parties £3,000 before VAT.

Costs also vary significantly by geographic location. London solicitors typically charge 30–50% more than regional equivalents. They also vary by solicitor reputation and specialization — a specialist family law firm with a strong track record will usually charge more than a high street generalist.

For a much more detailed breakdown of costs, including a comparison of the template route versus the bespoke solicitor route, and an interactive cost estimator, see our dedicated Prenup Cost UK page.