This is one of the most important limits to understand: a prenuptial agreement cannot decide anything to do with children. You can agree a great deal about your own finances, but where children are concerned the court – not your agreement – always has the final word. It is one of the two backstops (alongside needs) that no prenup can cross, and it flows from a principle the law treats as non-negotiable: a child’s welfare comes first.
This guide explains exactly what a prenup cannot do where children are involved, why the law works that way, and – importantly – the many things a prenup can still do around a family.
What a prenup cannot do
- Fix child maintenance. Parents cannot contract out of their duty to support their children. Child maintenance is dealt with separately – often through the Child Maintenance Service – and a court will not be bound by what a prenup says about it.
- Decide who children live with or spend time with. These arrangements are governed by the children’s welfare at the time, which only a court can assess – not by an agreement signed years before the children were even born.
- Limit provision the court thinks children need. A prenup cannot cap or exclude what is required to house and support the children of the family.
Trying to include such terms does not invalidate the whole document – those parts simply carry no weight (see what makes a prenup invalid).
Why the law works this way
When it comes to children, the law’s paramount concern is the child’s welfare, judged in the circumstances that actually exist when a decision is needed – not those a couple imagined years earlier. A parent cannot sign that protection away in advance, because the right being protected belongs to the child, not the parents. This is why children are one of the fixed limits on every agreement, as explained in are prenups legally binding? and Radmacher v Granatino, where the provision the husband received was framed around his role caring for the children.
Child maintenance vs spousal maintenance
It is worth separating two things people often conflate. Child maintenance – support for the children – is outside what a prenup can decide. Spousal maintenance – support between the adults – is something a prenup can address, within the limits the court allows (see spousal maintenance in a prenup and can you waive maintenance?). So while you cannot pre-agree what your children will receive, you can set a sensible framework for the adults’ finances around them.
What a prenup can still do around a family
Plenty. A prenup can set out how you will treat property, savings, a business, debts and inheritances between the two of you, and how those are handled on divorce or death. For families, some of the most valuable uses are:
- Protecting assets intended for children from a previous relationship – a central concern in a second marriage or blended family (see protecting children’s inheritance).
- Ring-fencing a family inheritance or a family business meant to pass down a generation.
- Leaving room to provide generously for children – the strongest agreements do exactly this, because an agreement that ignores children is one a court is far more likely to set aside.
A prenup also works best alongside an up-to-date will, so your wishes for children are reflected on death as well as divorce.
Having children after signing
Circumstances change, and few change a marriage more than the arrival of children. A prenup signed by a childless couple can start to look unfair once there are children to house and support – and remember that fairness is judged at the time of the divorce, not the wedding. That is why a review clause, prompting you to revisit the terms on a big life event like the birth of a child, is such a sensible feature. Our guide to what to include shows where the sensible lines are.
How courts factor children into a settlement
Even though a prenup cannot decide anything about children, children loom large in the financial settlement itself – because their needs come first. In practice this often means the parent who will care for the children needs suitable housing and enough income to do so, which can require a larger share of the assets than the prenup envisaged. The housing may be provided for the children’s minority and then revert; the exact approach depends on the family’s resources.
This is exactly what happened in cases such as Luckwell v Limata and Radmacher, where provision was made around the parent’s caring role. The lesson for drafting is clear: an agreement that leaves realistic room for the children of the family is far more likely to be respected than one that tries to squeeze them out (see the needs principle).
Blended families and second marriages
The tension between protecting assets and providing for children is felt most keenly in second marriages and blended families. Here a partner often wants to make sure that assets built up before the new relationship – perhaps intended for children from a first marriage – are not swept into a fresh division on a later divorce or death.
A prenup is one of the best tools for this, because it can ring-fence those assets clearly and record the couple’s shared intention that they pass to the children they were meant for (see protecting children’s inheritance). What the prenup still cannot do is decide anything about the day-to-day arrangements or maintenance for any children of the new relationship – that remains for the court.
And because a prenup only governs what happens between the couple, it should be paired with an up-to-date will so that your wishes are honoured on death as well. Used together, the two documents let a parent protect children from an earlier relationship while still treating a new spouse fairly.
A short worked example: a prenup and the children's needs
Imagine a parent remarrying in their fifties who owns a mortgage-free home they want eventually to pass to their two adult children. A prenup can record that this home is non-matrimonial and is to be preserved for those children, while making fair provision for the new spouse from other resources – perhaps a right to live in a property for their lifetime, or a share of jointly built savings.
That is a legitimate use of an agreement that a court is likely to respect, because it protects specific assets while still meeting the new spouse’s reasonable needs. But if the couple went on to have a child together, the court would insist that child be properly provided for, whatever the prenup said – and a review clause prompting them to revisit the terms on that birth would keep the agreement fair and robust.
Common misunderstandings about prenups and children
- “A prenup can set what my child gets.” No – child support and arrangements are for the court, judged on the child’s welfare at the time.
- “Mentioning children makes the prenup weaker.” The opposite: an agreement that leaves realistic room for children is far more likely to be upheld than one that ignores them.
- “A prenup is pointless once you have kids.” Not so – it can still protect pre-marital and inherited assets; it just cannot override what the children need.
- “Child maintenance and spousal maintenance are the same.” They are not – a prenup can address spousal maintenance within limits, but never child maintenance.
Prenups and children: what you cannot decide in advance
On prenups and children, the line is firm: you cannot fix child maintenance or decide who children live with in advance, because the court keeps control of anything affecting a child’s welfare. A prenup can still set the financial framework between the two of you – and the strongest agreements leave room to provide generously for children, since one that ignores them is far more likely to be set aside.
The three statutes behind the rule
The reason a prenup cannot touch children's arrangements is that three different Acts already give the answer, and none of them lets parents contract out. Child maintenance is governed by the Child Support Act 1991.
Under section 8 of the Child Support Act 1991, where the Child Maintenance Service has jurisdiction to make a maintenance calculation, the court may not make a maintenance order for the child at all, with limited exceptions, one of which is a consent order that embodies a written agreement. Even that exception is for an order made when the parents separate, and either parent can later go to the Child Maintenance Service, whose calculation then displaces the agreed figure.
A clause fixing child maintenance in a prenup signed years before any child was born has no purchase on that system.
Where children live and how much time they spend with each parent is decided under the Children Act 1989. Section 1 of the Children Act 1989 provides that when a court determines any question about a child's upbringing, the child's welfare shall be the court's paramount consideration, judged on the circumstances at the time. A parent cannot promise away that assessment in advance, and a court asked to enforce such a promise would be acting contrary to the statute.
The financial consequences of divorce for the parents are decided under section 25 of the Matrimonial Causes Act 1973, which gives first consideration to the welfare of any child of the family under eighteen before it turns to the adults' needs and resources. That is why the Supreme Court in Radmacher v Granatino said an agreement cannot prejudice the reasonable requirements of any children of the family, and why the strongest prenups, far from ignoring children, provide for their housing expressly and include a review clause triggered by a birth. An agreement that does that is simply anticipating what section 25 will require.
Standish v Standish and the children's needs
The test for whether a court gives effect to a prenup is still Radmacher v Granatino. The Supreme Court's 2025 decision in Standish v Standish answers a different question: what the court shares when there is no agreement. It held that the sharing principle applies to matrimonial property, the wealth a couple build up together, and that property one partner brought into the marriage, inherited or was given is shared only where the couple have treated it as shared over time. Needs still come first, from whichever kind of property can meet them.
For a couple making a prenup that cuts both ways. The law now starts closer to where most agreements end up, so an agreement that keeps pre-marital and inherited property separate asks the court for less. But whether an asset has become matrimonial is a question of fact, argued years later, and a prenup is the one document that records what you both brought in and what you agreed to treat as shared. The Law Commission's financial remedies scoping report, published in December 2024, set out models for reform with rules on nuptial agreements among them; none has yet become law. Our guide to what Standish v Standish means for prenups has the detail.
Prenups and children: FAQs
Can a prenup set child maintenance?
No – parents cannot contract out of supporting their children; child maintenance is handled separately.
Can a prenup decide who the children live with?
No – those arrangements are decided by the children’s welfare at the time, only by a court.
Does having children change a prenup?
It can make an old one look unfair, so build in a review clause and revisit the terms.
Can a prenup protect assets for children from a first marriage?
Yes – that is one of its strongest uses (see protecting children’s inheritance and second marriages).
Can a prenup deal with spousal maintenance?
Yes, within limits – unlike child maintenance, support between the adults can be addressed (see spousal maintenance in a prenup).
Will ignoring children weaken a prenup?
Yes – an agreement that makes no room for children is far more likely to be challenged and set aside (see the needs principle).
Can a prenup protect a home I want to leave to my children?
Yes – it can ring-fence that home as non-matrimonial, especially useful in a second marriage; pair it with an up-to-date will.
Should I update my prenup when a child is born?
It is wise to – a review clause that prompts you to revisit the terms on the birth of a child keeps the agreement fair and robust.
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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.