TL;DR: A prenuptial agreement is a written contract signed before marriage that lets a couple opt out of their state's default property and support rules. According to a 2023 Harris Poll for Axios, roughly 50% of U.S. adults now support prenups, and 47% of engaged or married Millennials report having one. You likely need one if you own a business, carry significant debt, expect an inheritance, have children from a prior relationship, or want to control how assets are divided rather than defaulting to state law.If you searched the word "prenup," you probably want a definition before anything else. Here it is. A prenup, short for prenuptial agreement, is a written contract two people sign before they get married. It sets out how they want to handle property, debts, and spousal support both during the marriage and if the marriage ends by divorce or death. The framework comes from the Uniform Premarital Agreement Act , drafted by the Uniform Law Commission in 1983 and adopted in some form by 29 states plus the District of Columbia, with a 2012 update called the UPMAA.
That's the legal definition. The practical one is shorter: a prenup is how a couple decides for themselves what happens to their money, instead of letting their state decide for them.
What does a prenup actually do? A well-drafted prenup typically covers four things. It defines what counts as each partner's separate property and what counts as marital property. It sets out how assets and debts will be divided if the marriage ends. It addresses spousal support, sometimes called alimony, including whether it will be paid and how much. And it spells out inheritance and estate rights, which matters especially for couples with children from a prior relationship or family assets they want to protect.
A prenup can also designate specific items: a business interest, a vinyl collection, a piece of family jewelry, even a pet. It cannot pre-decide child custody or child support. Those questions are resolved at the time of separation based on the child's best interests, and courts will not let parents bargain them away in advance. Lifestyle clauses (chores, social media, weight) are generally unenforceable as well; most judges will not police private behavior.
Here is a quick map of what a prenup can and cannot cover:
Topic
Can a prenup address it?
Notes
Separate property brought into the marriage
Yes
Often the core reason couples sign one
Division of assets acquired during marriage
Yes
Overrides default state rules
Debts (student loans, credit cards, business debt)
Yes
Can assign responsibility to one partner
Spousal support / alimony
Usually yes
Some states require independent counsel for waivers; others may revisit enforceability at the time of divorce
Inheritance and estate rights
Yes
Especially useful with children from a prior marriage
Business interests
Yes
Can designate a business as separate property
Child custody
No
Decided at separation based on the child's best interests
Child support
No
Cannot be waived in advance
Lifestyle clauses (chores, social media, weight)
Generally unenforceable
Courts rarely enforce these
Your state already has a "prenup" for you This is the part most people miss. If you do not sign a prenup, you are not avoiding one. You are accepting your state's version by default.
Even without an agreement, every couple is governed by their state's default rules for dividing property and debt if a marriage ends. Nine community property states (Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, Washington, and Wisconsin) generally treat most assets acquired during the marriage as jointly owned, according to Justia . The remaining 41 states and Washington, D.C. follow equitable distribution, where a judge divides marital property based on what is fair rather than by a fixed split, and "equitable" does not always mean "equal." A prenup replaces whichever set of default rules applies to you with terms you choose. (For a deeper breakdown, see our state-by-state guide to how prenups vary across America .)
Do I need a prenup? A decision framework A prenup is worth considering if any of the following applies to you or your partner:
You own a business or part of one. Without a prenup, growth in the business during the marriage may be treated as marital property, even if your partner never worked there.You have children from a prior relationship. A prenup helps make sure assets you want to pass to your kids actually reach them, instead of being absorbed into the marital estate.You expect a significant inheritance. Inheritance is often separate property in theory, but it can become commingled over a long marriage. A prenup can help keep it separate.You or your partner carries significant debt. A prenup can designate debt (such as student loans or business obligations) as one partner's responsibility, so the other isn't exposed.There's a meaningful income or asset gap between you. A prenup can address whether spousal support will be paid, how much, and for how long, rather than leaving it to a judge.You want to choose the outcome rather than default to state law. Even with simple finances, you may prefer your own rules to the ones your legislature wrote.If none of these apply, the default state rules may be acceptable to you. If you are unsure, that uncertainty is itself a reason to talk to an attorney before deciding.
Why couples are signing prenups now The conversation has shifted, as seen in First’s 2026 Prenup Report . According to a September 2023 Harris Poll for Axios , 50% of U.S. adults say they at least somewhat support the use of prenups, 47% of engaged or married Millennials report having one, and 41% of engaged or married Gen Z report the same.
Part of the explanation is timing. People are marrying later. The U.S. Census Bureau reports that in 2025 the median age at first marriage reached 30.8 for men and 28.4 for women, up from ages 23.5 and 21.1, respectively, in 1975. Couples are walking into marriage with more years of earnings, more retirement savings, more student debt, and in many cases ownership stakes in businesses or homes. There is simply more to talk about.
The other shift is cultural. Prenups used to be associated with celebrity divorces and old money. Today, they're a planning tool that younger couples often see as part of the same conversation as joint accounts, beneficiary designations, and estate plans. A prenup doesn't just protect "today you"; it protects "future you," too.
How to get one (briefly) The process has a few standard steps. It begins with a conversation between the two of you about what each of you wants the agreement to do. Both partners then complete full financial disclosure, listing assets, debts, income, and expected inheritances. From there, the agreement is drafted, each party reviews it with independent legal counsel (required in some states for enforceability, and strongly recommended in all), revisions are negotiated, and the final version is signed and notarized (notarization is not required in most states but can add an extra layer of authentication).
The most important practical rule: sign well before the wedding. Signing days before the ceremony can give a court reason to question whether one party felt pressured. Some states have specific timing rules; California, for example, requires the final draft to be delivered to both parties at least seven days before signing . State law and individual facts shape enforceability, so timing rules vary.
For a fuller walkthrough, see our prenup primer .
Frequently asked questions What is a prenup in simple terms? A prenup, short for prenuptial agreement, is a written contract two people sign before they get married. It spells out how they want to handle assets, debts, and spousal support during the marriage and if the marriage ends by divorce or death. Without one, state law decides those questions by default.
Do I already have a prenup if I never signed one? If you do not sign a prenup, your state's default rules decide how property and debt are divided if the marriage ends. Nine community property states treat most marital assets as jointly owned; the other 41 states and Washington, D.C. use equitable distribution, where a judge divides property based on what is fair. A prenup replaces those default rules with terms you choose.
Do I need a prenup? A prenup is worth considering if you own a business, expect an inheritance, carry significant debt, have children from a prior relationship, earn substantially more or less than your partner, or want to choose how assets are divided rather than rely on your state's default rules. It is not only for the wealthy.
What does a prenup cover? A prenup typically covers separate and marital property, division of assets and debts if you divorce, spousal support (alimony), inheritance and estate rights, and protection of business interests. It can also address specific items like a family heirloom or a pet. It cannot pre-decide child custody or child support.
Is a prenup worth it? For most couples with assets, debts, a business, children from a prior relationship, or a meaningful income gap, a prenup is worth the cost. It can reduce uncertainty, shorten a future divorce, and prompt useful conversations about money before marriage.
When should we sign a prenup? Sign well before the wedding, ideally several months out. Signing too close to the ceremony can give a court reason to question whether one party felt pressured. Some states have specific timing rules; California, for example, requires the final draft to be delivered to both parties at least seven days before signing.
Can a prenup be thrown out in court? Yes. A court can refuse to enforce a prenup if one party was coerced, did not have time to review it, or did not receive full financial disclosure. A court can refuse to enforce a prenup if the agreement is so one-sided it is considered unconscionable. In many states, unconscionability alone is not enough; the challenging party must also show they did not receive adequate financial disclosure. Independent legal review for each party significantly reduces that risk.
If you're ready to take the next step Deciding whether to sign a prenup is a personal decision, and there is no single right answer for every couple. What matters is that you make the choice with clear eyes, with full information about your state's default rules, and with a real conversation between you and your partner.
First was built to make that process collaborative and transparent, on your timeline. No hourly rates, no surprise invoices, no back and forth with attorneys you've never met. If you want to see how it works, you can start with First . And if you'd like more reading first, our guide to everything you need to know about getting a prenup is a good next stop.
Methodology These figures are drawn from the U.S. Census Bureau's 2024 Current Population Survey (median age at first marriage) and a September 2023 Harris Poll for Axios of U.S. adults (prenup attitudes and self-reported signing rates by generation). The list of UPAA and UPMAA adopting states comes from the Uniform Law Commission's official roster.
Sources
This post is educational and does not constitute legal advice. Prenup enforceability depends on state-specific rules and the facts of each case, so readers with specific questions should consult an attorney licensed in their state.
First is not a law firm. The information and tools provided by First on this site are not legal advice and not a substitute for the advice of an attorney.
