Can you get a prenup after marriage? A guide to postnups 

Author: Holly Atkins, Consultant Family Solicitor at Setfords | Last updated: 17^thAugust 2026 | Read time: 9 minutes

Can you sign a prenuptial agreement after getting married? Is it possible to create a postnuptial agreement in the UK? What is the difference between a prenuptial and postnuptial agreement? How soon after marriage can you get a postnup? Are postnuptial agreements legally binding? 

These are all questions we hear quite often. Often, people leave sorting out a pre-nuptial agreement to the very last minute before getting married, or when it is simply too late, so they wonder if it’s possible to sort it out once they are actually married.

Key takeaways 

• You cannot sign a prenup after the wedding, but a postnuptial agreement (postnup) can achieve the same goals at any time afterwards.
• There’s no deadline for a postnup, which removes the risk of a court refusing to uphold it due to pressure or duress.
• A valid postnup needs full financial disclosure, independent legal advice for both parties, and terms that are fair and freely agreed.
• A postnup cannot include contact arrangements for children.
• Postnups aren’t legally binding court orders, but courts give them strong weight when the right criteria are met.

Can you get a prenup after marriage? 

Guidance on pre-nuptial agreements suggests they should be signed no less than 28 days prior to the wedding. Leaving it to the last minute could appear as though one party was pressured into it, or it was not entered into freely, which means the court might not uphold the agreement in the future. To be able to enter into a Pre-Nuptial Agreement, you should therefore have instructed your legal representatives several weeks or months beforehand, to allow time to get everything together. However, we appreciate that sometimes that is not possible. 

The good news is that there is another option: a post-nuptial agreement (often called a postnuptial agreement or post nup). You can enter into a post-nuptial agreement at any time after marriage, and prior to any separation. So, can you get a prenup after marriage? Strictly speaking, you cannot sign a “prenup” once you are already married, but you can achieve the same goals with a postnuptial agreement (a post nup). 

What is a Post-Nuptial Agreement? 

A Post-Nuptial Agreement works well for couples who are already married, those who have missed the deadline for a Pre-Nuptial Agreement, and for those whose circumstances or priorities have changed since the wedding. In the UK, it is possible to create a postnuptial agreement, and a post nup can mirror many of the terms a couple might have put in a prenup. 

A Post-Nuptial Agreement sets out how you would like to divide your assets in the event of divorce. It clarifies who owns what, how assets and debts are to be treated, and what each person expects should happen in the event of separation. In short, while a prenuptial agreement is signed before the wedding, a postnuptial agreement (post nup) is signed after the wedding; that is the key difference between a prenuptial and postnuptial agreement. 

What can a Post-Nuptial Agreement cover? 

Post-Nuptial Agreements are drafted to suit the individual couple. The agreement can cover one point or many points, including: 

• Division of property already owned by either party or jointly
• Division of property acquired in the future by either party or jointly
• Financial provision for children
• Spousal maintenance
• Division of pension assets
• Payment of current or future debts held in sole names or jointly
• Arrangements for any gifts exchanged or received by either party from each other or from others
• Future inheritance that may be received by either party
• What you will leave by Will to the other party
• Arrangements for life insurance
• Ownership of business assets

Can a Post-Nuptial Agreement Cover Child Arrangements?

A Post-Nuptial Agreement can record the parties’ intentions regarding financial provision for their children. However, the court retains jurisdiction in relation to financial provision for children, and any agreement will be considered in light of the children’s needs and circumstances at the time.

A Post-Nuptial Agreement cannot determine arrangements for where children will live or the time they spend with either parent.

What are the advantages of a Post-Nuptial Agreement? 

Post-Nuptial Agreements are not very romantic, but they can save a lot of stress, time and money in the future. 

Entering into a Post-Nuptial Agreement can be a sensible choice at any time after the marriage, as you are no longer under the time pressure of signing the agreement 28 days before the wedding. There is no deadline, removing the risk of pressure, duress or entering into an agreement which you haven’t properly considered. Neither party can accuse the other of forcing them to sign the agreement to ensure the wedding goes ahead, which in turn helps the agreement to be upheld in the future. 

Parties have already experienced married life and may have a much clearer understanding of their financial circumstances, contributions and expectations than they did when contemplating marriage. A Post-Nuptial Agreement gives the opportunity to revisit and formalise financial arrangements in light of the current circumstances. 

Having the agreement in place can provide certainty and reduce the likelihood of future disputes or court applications. Provided the agreement is upheld, there should be less scope for lengthy negotiations or court proceedings, minimising legal costs and depletion of the parties’ finances. Divorce can be difficult enough to deal with. By having a Post-Nuptial Agreement in place, it can help avoid the need to negotiate every aspect of your finances, as you have already agreed the framework. 

Where two people in a marriage have a significant disparity in wealth, the wealthier person may wish to protect their wealth. A Post-Nuptial Agreement can help ringfence assets to ensure they stay within their family for future generations. 

You may have pre-marital assets you wish to protect, or you may have since inherited or acquired assets you weren’t expecting and that you now wish to protect. For example, you might have owned property prior to the marriage, or you may be about to inherit substantial wealth or gain a business interest, any of which you wish to keep separate. 

Post-Nuptial Agreements don’t have to just consider assets owned prior to the marriage. You can also set out what you would like to happen with assets which are accrued during the marriage. For example, future inheritance, bonuses at work, business interests or investments can all be protected. 

How soon after marriage can you get a postnup? 

You can get a Post-Nuptial Agreement at any point after you get married. In other words, if you’re asking “can you get a prenup after marriage,” the practical answer is to enter a postnuptial agreement (a post nup) as soon as you are ready; there is no minimum or maximum time limit. 

Can I turn a Pre-Nuptial Agreement into a Post-Nuptial Agreement? 

You cannot turn a Pre-Nuptial Agreement into a Post-Nuptial Agreement. However, if your financial circumstances have significantly changed, you have had children, or for any other reason you would like to make changes to your existing Pre-Nuptial Agreement, it is possible to ask your solicitor to prepare a new Post-Nuptial Agreement which records your current up-to-date intentions. 

Are Post-Nuptial Agreements legally binding? 

Whilst a Post-Nuptial Agreement is a written contract, they are not legally binding court orders in the UK. However, provided they follow strict criteria set by the Supreme Court, there is a strong presumption that a postnuptial agreement (post nup) will be upheld by the Family Court in the event of divorce. 

There are a few key matters which must be included in every agreement for it to be valid: 

Financial disclosure

Both partners must share all financial details openly. This means full disclosure of your income, assets, debts and pensions. 

Independent legal advice 

Each person should get independent legal advice. This is to ensure that you fully understand the terms of what you are signing and whether it is fair and sensible to enter into it. 

The agreement must be signed freely without pressure 

If you feel pressured to sign, it is likely that the agreement will be invalidated in the future. You should only ever sign if you are happy with the terms of the agreement. 

The agreement should be fair 

If the agreement is entirely unfair, or does not meet one party’s needs, it is less likely to be upheld. The ultimate decision as to whether your agreement should be upheld will always lie with the Judge in the event of a dispute. However, as long as you meet the above rules, your agreement should stand a very good chance of being valid. You should sign the agreement with an expectation that it will be upheld.

I am unsure whether a Post-Nuptial Agreement is for me 

If you are considering a Post-Nuptial Agreement, it is essential to get advice from an experienced family lawyer. They will be able to make sure that the terms of the agreement match your specific circumstances and that nothing is overlooked, including ensuring the agreement is fair to you and any children.  

For many couples in the UK asking “can you get a prenup after marriage,” the recommended route is a carefully drafted postnuptial agreement (post nup) tailored to their needs. For the agreement to be upheld in the future, it should always be reviewed by a solicitor on your behalf, as they can ensure you fully understand the terms and what you are signing. This is a legal requirement, and your solicitor will be asked to sign a certificate to confirm you have received appropriate advice. 

Entering into a Post-Nuptial Agreement will always be your own decision, however, your solicitor will be able to advise you if the agreement seems unfair and when you shouldn’t sign. 

About the author: Holly Atkins is a specialised family lawyer who deals with complex divorce, financial disputes, property and pension disputes and cohabitation matters. She is known for combining clear, strategic advice with a calm and approachable manner, helping clients navigate emotionally and financially challenging situations with confidence.

This article is general information about postnuptial agreements in England and Wales and is not legal advice. The law and timescales can change, and every situation is different, so please speak to a qualified family law solicitor about your circumstances.