Wondering how to get a postnup? Getting a postnuptial agreement follows much the same path as a prenup – the main difference is that you are already married, so there is no wedding deadline to work to. In short: agree together why you want one, exchange full financial disclosure, settle fair terms, prepare the agreement (online for a fixed fee or via a solicitor), each take independent legal advice, then sign it as a deed before a witness and store it safely. Below is each step in detail.
The sequence mirrors how to get a prenup, because the same steps are what give any nuptial agreement weight. The calmer, no-deadline setting of a postnup simply makes it easier to do each one properly.
1. Talk it through together
Start with an open conversation. Agree why you want a postnup and roughly what it should cover – a business, an inheritance, a property, or simply clarity about how you would divide things. Approaching it as a joint plan, calmly and without ultimatums, sets the right tone and helps the agreement stand up later. If raising it feels awkward, our guide to how to talk about an agreement applies just as well to a postnup.
2. Both give full financial disclosure
Each partner sets out their assets, property, savings, pensions, business interests, income and debts in a full and frank disclosure. This honest exchange is the foundation of a fair agreement – and skipping it is one of the surest ways to have an agreement set aside later. Attach the figures as a disclosure schedule; our guide to valuing your assets and the information you'll need will help.
3. Agree fair terms
Decide how separate and joint property are treated, and what happens on divorce or death – making sure both partners and any children are provided for. Fairness is not just decent; it is what makes a court more likely to uphold the agreement (see how to make it fair and when an agreement is unfair). Our guide to what to include applies equally to a postnup.
4. Prepare the agreement
Draft it online for a fixed fee, or through a solicitor. An online service produces a professionally structured agreement from £199, generated instantly as a PDF; a solicitor will draft a bespoke document for a higher fee (see how much a postnup costs). Either way, it should be set out professionally and correctly – a DIY effort that misses the essentials can be worse than none at all.
5. Take independent legal advice
Each partner takes their own independent advice on the finished agreement – ideally from separate solicitors, so neither is advised by the same person (see do both need a lawyer?). This is one of the things that most helps an agreement carry weight, because it shows each partner understood what they were signing (see are prenups legally binding?).
6. Sign it as a deed
Each partner signs freely in front of an independent adult witness who also signs – the agreement is executed as a deed. Then date and store the agreement safely with the disclosure schedule and advice letters. That is it – a clear, fair postnup in place.
What you will need to hand
Gathering your information before you start makes every later step smoother. Each partner should be ready to set out their assets and their value – property, savings, investments, pensions, business interests and any overseas assets – along with income and any debts. It helps to have recent statements, a current pension valuation (values can be much higher than people assume) and rough figures for anything harder to pin down. Our guide to the information you will need sets out a full checklist, and how to value your assets covers the trickier items. The more organised this stage is, the faster and cheaper the rest of the process tends to be.
How long does it all take?
The document itself can be produced quickly – an online agreement in an evening – but you should allow time for the steps that give it weight. Disclosure takes as long as it takes to gather honest figures, and each partner needs a genuine chance to take advice and reflect. With no wedding deadline, there is no reason to rush; taking a few weeks over it, rather than a few days, only strengthens the case that it was freely entered into.
Common mistakes to avoid
Most postnups that run into trouble later fail for the same handful of avoidable reasons. Steer clear of these and you remove the usual grounds of challenge:
- Skipping or skimping on disclosure. Leaving out an asset – even innocently – is one of the surest ways to have an agreement set aside.
- Rushing the signing. Even without a wedding deadline, pushing a partner to sign quickly invites a later claim of pressure.
- One-sided terms. An agreement that leaves one partner with almost nothing is likely to be judged unfair and may not be upheld.
- Skipping independent advice. If one partner never had their own advice, the agreement carries less weight.
- Getting the signing wrong. A postnup should be executed as a deed before an independent witness – not just signed casually.
- Never revisiting it. An agreement that no longer fits your lives is easier to challenge; build in a review clause.
A worked example of the timeline
Imagine a couple who decide in the new year to put a postnup in place after one of them inherited some money. In week one they talk it through and agree what it should cover. Over the next fortnight they each gather their financial information and exchange a disclosure schedule. They draft the agreement online, then each take it to their own solicitor for independent advice – a week or two to get appointments and make any tweaks. A few weeks after they started, they sign as a deed before witnesses and store it safely. No stage was rushed, and the unhurried timeline itself helps show the agreement was entered into freely.
When to involve a solicitor
You do not need a solicitor to make a valid postnup, but independent advice for each partner is strongly recommended, and there are situations where it is especially worth it: where finances are complex – a business, a trust, overseas assets or several pensions – where there is a significant imbalance between the partners, or where you simply want the reassurance that everything has been done correctly. A cost-effective route many couples take is to draft the agreement online for a fixed fee and then pay only for advice on the finished document (see online vs solicitor).
How to get a postnup without the stress
Knowing how to get a postnup is mostly about order and calm: agree together why you want one, exchange full financial disclosure, settle fair terms, prepare the agreement (online for a fixed fee or via a solicitor), each take independent legal advice, then sign it as a deed before a witness and store it safely. With no wedding deadline, you can take the time to do each step properly.
Getting both partners on board
A postnup only works as a shared decision, so the way you raise it matters as much as the steps that follow. Approach it as something you are doing together to bring clarity and fairness to your finances, not as a demand or a test of commitment. Explain the practical reason – an inheritance you both want to keep in the family, a business you want to protect, or simply the wish to know where you each stand – and give your partner room to think, ask questions and take their own advice. An agreement one partner feels railroaded into is not only unkind; it is legally fragile, because a court asks whether the agreement was freely entered into. If the conversation feels daunting, our guide to how to talk about an agreement gives you a calm way in that applies just as well after the wedding.
After the postnup is signed
Signing is not quite the end of the job. Store the executed deed somewhere safe, together with the disclosure schedule and both partners’ advice letters, and make sure each of you knows where it is kept – our guide to storing your agreement covers the practicalities, and what happens if it is lost is worth a read too. It is also worth checking that the rest of your planning lines up: an up-to-date will should sit comfortably alongside the postnup rather than contradict it. Finally, diary a future review. Circumstances change, and an agreement revisited under a review clause when your lives shift stays fairer, and more robust, than one signed once and never looked at again (see after signing).
How to get a postnup: FAQs
How long does a postnup take?
The document can be quick; allow a few weeks for disclosure and advice so nothing is rushed (see how long an agreement takes).
Do you need a solicitor for a postnup?
Not to make it valid, but independent advice for each partner is strongly recommended (see do you need a solicitor?).
Can you get a postnup online?
Yes – you can draft a professionally structured agreement online from £199, then take independent advice on it (see online vs solicitor).
Does a postnup need to be witnessed?
Yes – it should be signed as a deed in front of an independent witness (see who can witness it?).
What do you need before starting a postnup?
An honest picture of both partners' finances – assets, income and debts. See the information you'll need.
What happens after you sign a postnup?
Store it safely with the disclosure and advice letters, and revisit it if your circumstances change – ideally under a review clause (see after signing).
Can we write a postnup ourselves?
You can, but a DIY document that misses disclosure, fairness or correct signing can be worse than none. A structured online agreement plus independent advice is safer and still inexpensive.
Do both partners need to want the postnup?
Yes – it should be a shared decision, freely made. An agreement forced on a reluctant partner risks being set aside for duress.
Where should we store the signed postnup?
Keep the signed deed with the disclosure schedule and both advice letters somewhere safe, and tell each other where it is (see storing your agreement and what if it is lost).
Create your prenuptial agreement online
UK Prenup lets couples in England & Wales create a clear, fair prenuptial agreement online from £199, with your document generated instantly as a PDF. See how it works or get started.
UK Prenup is not a law firm and does not provide legal advice. A prenuptial agreement in England & Wales is not automatically binding, and both partners should take independent legal advice before signing.