In this guide(11 sections)
If you're thinking about a prenup, you've probably already had — or are dreading — a slightly awkward conversation with the person you love. That's completely normal. The good news: a prenup isn't planning for failure. Talking openly about money before you marry or move in together is one of the kindest things a couple can do, because it means nobody is ever left guessing. Below is exactly how prenups work in Australia, in plain English — and if any of it feels daunting, you don't have to work it out alone. Elisa can talk it through with you; just fill in the enquiry form and she'll call you back. The first 30 minutes are free.
At a glance — prenups in Australia
| What a prenup is in Australia | A Binding Financial Agreement (BFA) made before marriage, or before or while living together |
| The law | Family Law Act 1975 (Cth) — s90B (before marriage), s90UB (de facto couples) |
| Are they legally binding? | Yes, if the strict requirements in s90G (or s90UJ for de facto couples) are met |
| The key requirement | Each person gets independent legal advice from their own lawyer before signing |
| What it can cover | Property, superannuation, financial resources and spousal maintenance |
| What it can't cover | Parenting arrangements; child support needs a separate child support agreement |
| When it can be set aside | Non-disclosure, fraud, duress, undue influence, unconscionable conduct and other grounds in s90K |
| Best timing | Start several months before the wedding — never days before |
| Typical cost (market) | Around $3,500 to $10,000+ per person, depending on complexity |
| Fogarty Oliver Rothschild | Pre-nuptial BFA from $4,400; halachic prenup + civil BFA from $5,500 — your fee confirmed in writing after a free 30-minute consultation |
Are prenups legally binding in Australia?
Yes — a prenup is legally binding in Australia when it is made as a Binding Financial Agreement under the Family Law Act 1975 (Cth) and the strict requirements are met. Couples planning to marry make one under section 90B; de facto couples under section 90UB. For the agreement to bind you, section 90G (section 90UJ for de facto couples) requires that it's in writing and signed by both of you, that each of you received independent legal advice about its effect on your rights and its advantages and disadvantages before signing, and that each of you was given a signed statement from your lawyer confirming that advice. Miss any of those steps and the agreement may not be binding at all.
The first 30 minutes are free, with no obligation. Book a free consultation → · or speak to Eliana, our assistant, any time on 03 4328 5084 — she'll get your matter to Elisa quickly.
What can a prenup cover — and what can't it?
A prenup can set out how you'll divide property, superannuation and other financial resources if you separate, and whether either of you will pay spousal maintenance. Couples most often use one to protect:
- Assets brought into the relationship — a home, savings, shares
- A family business or a share in one
- An expected inheritance or family wealth
- Provision for children from an earlier relationship
What it can't do: a prenup can't decide parenting arrangements — the court always decides those according to the children's best interests — and it can't on its own fix child support, which needs a separate child support agreement. It also doesn't replace a will. If protecting family wealth is part of the reason for the prenup, it's worth reviewing your wills at the same time.
Why do we each need our own lawyer?
Independent legal advice is the heart of a binding prenup. The same lawyer can't advise you both, because the advice has to be about each person's own rights and interests. So Elisa acts for one of you, and your partner engages their own lawyer. It can feel like an extra step, but it protects you both — an agreement signed without proper independent advice is one of the most common reasons a prenup fails.
Not sure whether a prenup, a later financial agreement, or nothing at all is right for you? Our guide to divorce vs consent orders vs a financial agreement explains the options side by side.
When can a prenup be set aside?
Under section 90K of the Family Law Act, a court can set a financial agreement aside only in limited circumstances, including:
- Non-disclosure or fraud — one person hid significant assets, debts or income
- Duress, undue influence or unconscionable conduct — one person was pressured into signing, or the other took unfair advantage of a weaker position
- A material change relating to children — for example, the birth of a child causing hardship the agreement didn't provide for
- The agreement has become impracticable to carry out
The High Court's 2017 decision in Thorne v Kennedy is the case most lawyers point to: a prenup signed under pressure shortly before the wedding, against the lawyer's advice, was set aside for undue influence and unconscionable conduct. The lesson is simple and kind: give each other time, disclose everything, and never make signing a condition of the wedding going ahead.
What goes wrong with prenups?
These are the situations we see most often when prenups come apart — described generally, not as any particular client's matter:
The agreement signed the week before the wedding. The invitations are out, the venue is booked, and one partner is handed an agreement to sign. Even with legal advice, an agreement signed under that kind of pressure is exposed to being set aside for duress or undue influence.
The asset nobody mentioned. One partner leaves out a business interest, an investment property or a trust. Years later, when the relationship ends, the non-disclosure becomes the reason the whole agreement fails.
The agreement that didn't grow with the family. A prenup made when neither partner had children says nothing about what happens if one stops work to raise them. When that's exactly what happened, the agreement may no longer be fair — and a significant change relating to children is one of the grounds for setting it aside.
None of these mean prenups don't work. They mean the way a prenup is made matters as much as what it says.
How long before the wedding should we start?
Ideally several months. That gives you both time to gather full financial disclosure, get independent advice, talk through anything you don't agree on, and sign without any sense of pressure. If your wedding is close, it may be wiser to sign after the wedding instead — a financial agreement can also be made during the marriage.
Short on time before the wedding? That's exactly what the free first call is for. Book a free 30-minute call → · or reach Eliana any time on 03 4328 5084
What does a prenup cost in Australia?
Across the market, a prenup typically costs from around $3,500 to $10,000 or more per person, depending on how complex your finances are — trusts, businesses and overseas assets all add work. At Fogarty Oliver Rothschild, a pre-nuptial Binding Financial Agreement starts from $4,400, and a halachic prenup combined with a civil BFA starts from $5,500. Your own fee is confirmed in writing after a free 30-minute consultation, once it's clear what your situation actually needs, and before any work starts. Your partner's independent lawyer charges separately. For a fuller breakdown, see what a Binding Financial Agreement costs.
How we make it easy: (1) a free, unhurried first call · (2) your fee in writing · (3) we draft the agreement around what you both want to protect · (4) your partner gets their own advice · (5) you sign with time to spare — no pressure, no surprises.
Does a prenup still work if we have children or our circumstances change?
A prenup is written at one point in time, and life moves on. Having children, a big change in wealth, or one of you leaving work to care for family can all affect whether the agreement still works fairly. It's wise to review your agreement when big things change, and to build sensible review points into it from the start.
Frequently asked questions
Are prenups legally binding in Australia?
Yes. A prenup is binding in Australia when it's made as a Binding Financial Agreement under the Family Law Act 1975 (Cth) and the requirements in section 90G are met — most importantly, that each person received independent legal advice before signing and a signed statement from their lawyer confirming it.
Can de facto couples have a prenup?
Yes. De facto couples can make a financial agreement before moving in together, while living together, or after separating, under section 90UB of the Family Law Act. In Western Australia, de facto financial agreements are made under the Family Court Act 1997 (WA).
Can we use one lawyer for a prenup?
No. Each person must receive independent legal advice from their own lawyer for the agreement to be binding. Elisa acts for one of you only.
How much does a prenup cost in Australia?
Typically from around $3,500 to $10,000 or more per person, depending on complexity. At Fogarty Oliver Rothschild, a pre-nuptial BFA starts from $4,400, with your fee confirmed in writing after a free 30-minute consultation.
Can a prenup be overturned?
It can, but only on limited grounds in section 90K of the Family Law Act — such as non-disclosure of assets, fraud, duress, undue influence, unconscionable conduct, or a significant change relating to children. Full disclosure, independent advice and plenty of time before signing are what make a prenup hold.
Can a prenup cover child support or custody?
No. Parenting arrangements are always decided according to the children's best interests, and child support needs a separate child support agreement. A prenup deals with property, superannuation and spousal maintenance.
Can we make an agreement after the wedding instead?
Yes. A Binding Financial Agreement can be made before marriage, during the marriage, or after separation. If your wedding is very close, signing afterwards is often the safer choice.
Feeling unsure? That's exactly what Elisa is here for
Wanting to protect what you've built — while protecting the relationship too — is a good instinct. Elisa helps couples do this calmly and fairly, in plain language, with the fee agreed in writing up front.
The first 30 minutes are free.
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Written and reviewed by Elisa Rothschild BA/LLB — Principal Lawyer, Fogarty Oliver Rothschild. Admitted to legal practice in Victoria. Family and property law in Melbourne since 2012.Last reviewed 6 October 2026.
This guide is general information about Australian family law, not legal advice for your specific situation. For advice on your matter, book a free 30-minute consultation.