You cannot enter into a prenuptial agreement once you are already married. However, you can put broadly similar financial arrangements in place through a postnuptial agreement, which is made after the marriage or civil partnership has begun.

If you wanted to get a prenup but did not sign one before the wedding, you can still agree how key assets should be treated if the relationship later ends. A postnuptial agreement can also update an existing prenup when circumstances change.

JMW's prenuptial agreement solicitors advise on both prenuptial and postnuptial agreements, including arrangements involving substantial or complex financial assets. Speak to our family law team in confidence on 0345 872 6666, or complete our online enquiry form to arrange a call at a time that suits you.

What Is a Postnuptial Agreement?

A postnuptial agreement is a written agreement made by spouses after they are married. It sets out how they intend their assets, liabilities and other financial arrangements to be treated if the marriage later ends.

A postnuptial agreement can establish new arrangements or update an agreement entered into before the marriage. It may cover the family home, other property, savings, investments, business interests, pensions, inherited assets, trust interests, future inheritance and current or future debts.

It can also address financial provision if the relationship ends, giving both parties greater clarity about their intentions.

A postnup does not replace the Family Court's powers on divorce, and postnuptial agreements are not automatically legally binding in England and Wales. However, a properly prepared agreement can have significant legal standing if both parties entered into it freely, understood its implications and it would be fair to hold them to its terms.

For a fuller explanation, read our guide to what a postnuptial agreement is.

What Is the Difference Between a Prenup and a Postnup?

Prenuptial and postnuptial agreements are designed to deal with many of the same financial issues. The key difference is when the agreement is made.

A postnup is not automatically weaker simply because it is made after marriage. In both cases, the court will look at how the agreement was entered into, what information and legal advice each party received, and whether it would be fair to give effect to the agreed terms.

For some couples, a postnuptial agreement may actually provide more time to consider the arrangements carefully because there is no wedding deadline approaching.

What if You Started a Prenup but Did Not Sign It Before the Wedding?

If you started work on a prenuptial agreement but married before it was completed and signed, you can usually revisit the proposed arrangements through a postnuptial agreement.

Once you are married, an unfinished prenup should not simply be treated as though the wedding has not happened. The document and advice need to reflect your current position.

An existing draft can still provide a useful starting point. Your solicitor can review what had been agreed, identify unresolved points and update the financial information where necessary.

Crucially, neither person should feel pressured to sign simply because they had previously intended to complete a prenup. Each party should receive independent legal advice on the postnuptial agreement and have enough time to understand what the proposed terms mean for them.

If you want more detail on the practical stages involved, read our guide to how a postnuptial agreement works in the UK.

What Can a Postnuptial Agreement Cover?

A postnuptial agreement can cover most of the financial matters that might otherwise become relevant if a marriage or civil partnership ends. The exact terms should match the couple's specific circumstances rather than following a standard template.

A postnuptial agreement may address:

• The family home and other property
• Savings, investments and bank accounts
• Business interests, including a family business
• Pension assets and how the parties intend them to be treated
• Inherited wealth and future inheritance
• Gifts received during the marriage
• Trust interests and wider family wealth
• Assets held by one party or held jointly
• Current or future debts and other liabilities
• Financial provision or maintenance if the relationship ends

A postnup can provide clarity about financial interests, but there are limits to what it can decide. In particular, parents cannot conclusively determine future child arrangements in a financial agreement. Decisions concerning children must reflect their welfare and best interests at the relevant time.

Are Postnuptial Agreements Legally Binding?

Postnuptial agreements are not automatically legally binding in England and Wales. The Family Court retains the ultimate decision over financial arrangements on divorce or civil partnership dissolution.

However, that does not mean a postnuptial agreement has little legal standing. The Supreme Court's decision in Radmacher v Granatino [2010] UKSC 42 established that the court should give effect to a nuptial agreement entered into freely by parties with a proper understanding of its implications unless it would be unfair to do so in the circumstances.

In practice, a robust postnuptial agreement is more likely to carry substantial weight where:

• Both parties entered into the agreement voluntarily and without improper pressure
• Each party received independent legal advice from their own solicitor
• There was full financial disclosure of relevant assets, liabilities and resources
• Both parties understood the agreement and its consequences
• The terms were fair when agreed and remain fair in the circumstances
• The reasonable needs of both parties and any children have been properly considered

The court will still consider the wider statutory factors that apply to financial provision on divorce, including those under section 25 of the Matrimonial Causes Act 1973.

For more detail on this point, read our guide on whether postnuptial agreements are legally binding in the UK.

Why Might You Get a Postnup After Marriage?

A couple can decide to get a postnuptial agreement at many points during their marriage. It does not need to follow a dispute or relationship difficulty, and choosing to make one does not in itself mean that the relationship is expected to end.

Common reasons include:

• A prenuptial agreement was discussed or drafted but was not completed before the wedding
• One party has received, or expects to receive, a significant inheritance
• A business has been created, sold or has increased substantially in value
• The couple has acquired new property or investments
• One spouse or civil partner has reduced or stopped work to care for children
• Trust interests or other family wealth have become more significant
• One party has taken on significant debts or financial obligations
• The parties' income, assets or wider financial circumstances have materially changed
• An existing prenuptial agreement no longer reflects the couple's circumstances

A postnup can also put both parties on the same page about ownership, expectations and long-term planning during the marriage.

Read more about why you might consider a postnuptial agreement.

How Do You Make a Postnuptial Agreement?

The process should reflect the parties' assets, objectives and specific circumstances.

1. Decide what the agreement should achieve

An experienced family lawyer can help identify which assets and future arrangements need to be covered. This may involve a particular inheritance or business, or a broader agreement dealing with the couple's finances as a whole.

2. Exchange financial disclosure

Both parties should provide appropriate financial disclosure so each understands the other's assets, income, liabilities and resources. Full financial disclosure is particularly important where the arrangements involve businesses, trusts, property portfolios or other complex assets.

3. Agree and negotiate the terms

The parties and their solicitors can then work through the proposed terms. A specialist family lawyer should consider not only what one party wants to protect, but whether the agreement as a whole is fair and workable.

4. Obtain independent legal advice

Each person should have their own solicitor and obtain independent legal advice before signing. One family lawyer cannot advise both parties on whether the agreement protects their individual position.

5. Finalise the written agreement

Once both parties understand the terms and are willing to proceed, the postnuptial agreement can be finalised and signed. Depending on the circumstances, it may also include provisions for reviewing the agreement after a set period or following major life or financial changes.

How Much Does a Postnuptial Agreement Cost in the UK?

There is no single fixed cost for a postnuptial agreement. Legal fees will depend on the complexity of the assets, the amount of disclosure required, whether businesses, trusts or overseas property are involved, and how much negotiation is needed.

Each party should usually have their own solicitor, so they will incur separate legal fees. A family lawyer can explain the likely cost once the scope of the agreement and your financial circumstances are clear.

Can You Change a Prenup After You Are Married?

If you already have a prenuptial agreement, a postnuptial agreement can be used to reaffirm, update or replace its terms after marriage.

This may be appropriate after children, an inheritance, business growth or sale, major new assets, an overseas move or another significant change.

The new terms should be properly recorded rather than added informally to the original document. Both parties should seek independent legal advice before agreeing them.

Can You Make a Postnup Years After Getting Married?

There is no fixed point during a marriage after which it is too late to make a postnuptial agreement. A couple may make one shortly after the wedding or many years later.

What matters is whether the agreement properly reflects the parties' circumstances at the time. In a longer marriage, issues such as the family home, pension provision, career decisions, children, business interests and jointly accumulated assets may look very different from when the couple first married.

There is therefore no fixed entitlement simply because somebody has been married for a particular number of years. If the marriage later ends, the court considers the parties' circumstances and the applicable legal factors when deciding a fair financial settlement. JMW's financial settlement solicitors can advise on how these principles apply in individual cases.