Prenuptial Agreements Explained

A prenuptial agreement is a written contract made before marriage that sets out how a couple would divide their money, property and other assets if the relationship were to end. Once seen as unromantic or the preserve of the very wealthy, prenups have moved firmly into the mainstream, driven by later marriages, second marriages, family businesses and the simple wish to make a difficult conversation calmly, in advance, rather than in the heat of a breakup.

This guide explains how prenups work in England and Wales, why they are not quite as binding as many people assume, and the practical steps that give one the best chance of being upheld. It is information rather than personal legal or financial advice, every family is different, and the value of investments and businesses can fall as well as rise.

What a prenuptial agreement is

A prenuptial agreement, often shortened to “prenup”, is signed before the wedding and typically records three things: what each person owns going into the marriage, what should happen to those assets on divorce, and how any wealth built up during the marriage should be shared. A near-identical document signed after the wedding is called a postnuptial agreement, or postnup, and is treated by the courts in much the same way.

The motivation is rarely mistrust. More often it is clarity: a person entering a second marriage who wants to protect assets for children from the first; a family that has gifted or lent money and wants it ring-fenced; a founder protecting a business that pre-dates the relationship; or simply two people who would rather agree the terms while they are happy than argue them while they are not. Because the emotional and financial stakes overlap, many couples find it helps to take parallel legal and financial planning advice so the numbers behind the agreement are sound.

Prenups are no longer unusual. Later first marriages mean people bring more into a relationship, a flat bought alone, a pension already part-built, a stake in a family firm. Blended families are common, and a parent may want to guarantee that certain assets ultimately reach their own children rather than being absorbed into a new marriage. Understood in that light, a prenup is less a bet against the relationship and more a piece of sensible estate and financial planning, made while both people are calm and well disposed towards each other.

Are prenups legally binding?

This is the single most misunderstood point. In England and Wales a prenuptial agreement is not automatically binding on the divorce courts. Judges retain a statutory discretion under the Matrimonial Causes Act 1973 to decide what is fair, and no couple can contract out of that jurisdiction entirely. In Scotland the position is somewhat firmer, as agreements are more readily treated as binding contracts.

That said, the law shifted decisively in 2010. In the Supreme Court case Radmacher v Granatino, the court held that it should give effect to a nuptial agreement that was “freely entered into by each party with a full appreciation of its implications”, unless it would be unfair to hold the parties to it. In practice this means a well-drafted prenup now carries considerable weight, often decisive weight, even though it is not, strictly, the last word.

The Law Commission has recommended going further, creating a category of “qualifying nuptial agreements” that would be binding provided certain safeguards were met. That reform has not yet become law, but it signals the clear direction of travel: courts and policymakers increasingly expect adults to be held to the fair bargains they make. For now, the practical message is that the quality of the agreement, how it was made, not just what it says, determines how much weight a judge gives it.

What a prenup can cover

A prenup is flexible, but the more common provisions cluster around a few themes. The table below sets out what couples typically address and why.

What a prenup cannot do is bargain away the needs of children or dictate arrangements for their care: a court will always put a child’s welfare first. Nor can it lock in an outcome so lopsided that one spouse is left unable to meet reasonable needs. Pensions deserve special mention: they are frequently the second-largest asset in a marriage after the family home, and how they are shared can be complex, as our guide to how pensions are split in divorce explains. A prenup can record an intention about pensions, but the eventual division still has to be fair in the round.

The five requirements that make one stick

Following Radmacher, family lawyers work to a practical checklist. Meet these and a prenup is far more likely to be upheld; fall short on any and you hand the other side an argument to set it aside.

• 1

  Full financial disclosure

  Both parties must lay out their assets, income and debts honestly. Hiding wealth is the fastest way to have an agreement thrown out.

• 2

  Independent legal advice

  Each person should take advice from their own solicitor, so neither can later claim they did not understand what they were signing.

• 3

  No undue pressure

  The agreement must be entered into freely. Signing under duress, or at the last minute, badly weakens it.

• 4

  Signed in good time

  Aim to complete at least 28 days before the wedding, ideally months ahead, to rebut any suggestion of pressure.

• 5

  Fair and needs-aware

  The terms must not leave either spouse or the children in real need. Building in periodic reviews keeps it fair as life changes.

A common and sensible refinement is a review or “sunset” clause, for example, revisiting the agreement after the birth of a child or every five years. Circumstances that felt fair at 30 can look very different at 45 with two children and a jointly built business, and a court is more sympathetic to an agreement that has been kept current. An agreement drafted once and never revisited is more vulnerable to the argument that it no longer reflects the couple’s real life.

Disclosure is worth dwelling on, because it is where many home-made agreements fall down. Full and frank disclosure means schedules of property, savings, investments, pensions and debts, with values, not vague descriptions. If one partner later shows that assets were understated or hidden, a judge may conclude the other never truly understood what they were giving up, and set the agreement aside. Getting this right at the outset is far cheaper than defending a flawed document years later.

The timeline and process

A prenup is not a same-week job. Rushing it is precisely what undermines it. A realistic sequence looks like this:

1. Open the conversation early, ideally six months or more before the wedding, so it does not feel like an ultimatum.
2. Each partner instructs their own solicitor.
3. Both complete full financial disclosure, listing assets, income, pensions and debts.
4. Draft terms are negotiated and refined between the two solicitors.
5. Each party receives written legal advice on what they are signing.
6. The agreement is signed and dated, comfortably before the wedding.

What a prenup costs

Legal costs vary with complexity, but a straightforward prenup typically runs into a few thousand pounds when both parties are advised, more where there is a business, trust or international element. Set against the emotional and legal cost of a contested divorce, where fees can run to tens of thousands, many couples view it as modest insurance. Where a company is involved, our guide to business value and financial planning shows why early clarity is worth so much.

It is worth being honest about the limits, too. A prenup cannot make an unfair outcome fair, and it will not shield you from every claim. What it does is set the starting point and shift the burden: a judge who sees a properly made agreement will usually ask why they should depart from it, rather than starting from a blank page. That change in the centre of gravity is precisely its value.

Postnups and other options

If the wedding has already happened, a postnuptial agreement achieves much the same aim and is weighed by the courts on similar principles. Unmarried couples living together may instead use a cohabitation agreement and declaration of trust, since, contrary to the “common-law marriage” myth, they have very limited automatic rights on separation. And whatever route you take, the financial side benefits from planning that looks beyond the split itself to pensions, tax and long-term security. A regulated adviser can model how different settlements would actually play out, and our divorce and separation hub brings the money questions together.

Matching with an independently vetted, FCA-regulated adviser through Vetted Wealth is free, and it can be reassuring to have someone who understands the numbers sitting alongside your solicitor. This remains information rather than personal advice: the right approach depends on your own circumstances, and the value of investments can fall as well as rise.

Common questions on divorce & separation