A prenuptial agreement is a written contract that two people sign before they marry, setting out how property, debts, and spousal support will be handled if the marriage ends in divorce or death. It takes effect the moment the marriage becomes legal and replaces the default rules your state would otherwise apply. About 28 states and the District of Columbia have adopted a version of the Uniform Premarital Agreement Act or its successor, the Uniform Premarital and Marital Agreements Act, which give these contracts a standardized framework.
What a Prenup Replaces
Without an agreement, state law decides nearly everything. Community property states generally treat anything earned during the marriage as owned equally by both spouses. The rest use equitable distribution, where a judge divides marital property based on what seems fair under the circumstances. Fair does not always mean equal, and the outcome can be unpredictable.
A prenup lets you write your own rules instead. You can decide which assets stay separate, how jointly acquired property gets split, and whether either spouse receives support after a divorce. You can also address what happens at death, including whether to waive inheritance rights, homestead protections, or the elective share many states guarantee a surviving spouse. That predictability is the point of the document.
What You Can Put in a Prenup
The scope is broad. Under the Uniform Premarital and Marital Agreements Act, parties may contract over each spouse’s rights in any property either of them owns, whenever and wherever it was acquired. In practice, prenups cluster around a few recurring subjects.
Property and Debt
The most common use is labeling specific assets as separate property so they stay with their original owner. Real estate you owned before the wedding, an inheritance, or a brokerage account you built on your own can all be designated as yours alone. The agreement can also address how any increase in value on those assets gets treated, which matters because growth on separate property can become marital property depending on what caused the growth and which state you live in.
Debts work the same way. If one partner enters the marriage with substantial student loans or credit card balances, the agreement can keep those obligations with that person and shield the other spouse from liability they did not create.
Spousal Support
Couples can set a specific monthly payment, cap how long support lasts, or waive it entirely. Some agreements tie support to the length of the marriage, providing nothing for a short marriage and more for a longer one. These provisions replace the uncertainty of having a judge decide alimony based on income disparity and earning capacity.
Support waivers get heavier scrutiny than property terms. Under the model act, a court can refuse to enforce a support provision if doing so would leave a spouse eligible for public assistance at the time of enforcement.1Uniform Law Commission. Premarital and Marital Agreements Act Some states also require that the spouse giving up support had their own lawyer, and without that representation the waiver is void.
Business Interests
Protecting a business is one of the most practical reasons to sign a prenup. The contract can keep the business itself as separate property and set the rules for how any increase in its value during the marriage gets treated. Courts often distinguish between passive appreciation driven by market forces and active appreciation driven by a spouse’s work. A prenup can lock in which category applies and how to calculate each spouse’s share, which avoids a contested business valuation during a divorce.
The agreement can also grant each spouse the right to buy, sell, or manage property independently during the marriage without the other’s consent.1Uniform Law Commission. Premarital and Marital Agreements Act For someone running a company, day-to-day operations and major transactions no longer require spousal sign-off.
Estate and Inheritance Rights
Prenups also shape what happens when a spouse dies. Most states give a surviving spouse an elective share, often one-third of the estate, that can be claimed regardless of what the will says. A prenup can waive or modify that right, along with homestead protections, family allowances, and other statutory claims against the estate.1Uniform Law Commission. Premarital and Marital Agreements Act This matters most for people entering second marriages who want to preserve assets for children from a prior relationship.
What a Prenup Cannot Do
Some subjects are off-limits no matter how carefully the agreement is written. The model act prohibits terms that regulate behavior during the marriage, prescribe fault-based grounds for divorce, define custody or parenting time, or reduce a child’s right to financial support.1Uniform Law Commission. Premarital and Marital Agreements Act
Child support belongs to the child, not the parent, and judges decide child-related issues based on the child’s best interests at the time of the proceeding. A provision written years before a child is born cannot account for the child’s actual needs, and courts will not be bound by it. Agreements also cannot require either party to do anything illegal or include terms so one-sided they shock the conscience of the court.
Infidelity Clauses
Infidelity clauses, which impose a financial penalty on a cheating spouse, sit in uncertain territory. There is no uniform rule on whether courts will enforce them. In states where adultery still affects divorce or remains on the books as a criminal offense, a penalty provision may align with existing public policy. In strictly no-fault states, courts have refused to enforce these clauses because marital fault is legally irrelevant to divorce outcomes. Even where they are enforceable, proving adultery invites exactly the kind of contested litigation a prenup is supposed to prevent, and most family law attorneys advise against them.
The Retirement Account Problem
A prenup cannot override federal protections on retirement accounts governed by ERISA, including 401(k) plans, pensions, and most employer-sponsored retirement benefits. Federal law requires that only a spouse can consent to waive survivor benefits on these accounts. A person signing a prenup is a fiancée, not yet a spouse, so the waiver fails.2Office of the Law Revision Counsel. 26 USC 417 – Definitions and Special Rules for Purposes of Minimum Survivor Annuity Requirements
A valid waiver requires written consent from the spouse, a designated alternate beneficiary, acknowledgment of the election’s effect, and witnessing by a plan representative or notary public.3Office of the Law Revision Counsel. 29 USC 1055 – Requirement of Joint and Survivor Annuity and Preretirement Survivor Annuity A prenup almost never meets these requirements. The practical workaround is signing a separate spousal waiver after the wedding and, if the marriage later ends, dividing the account through a Qualified Domestic Relations Order, which is a court order recognized by the plan administrator.4U.S. Department of Labor. QDROs – An Overview FAQs The prenup can commit both parties to executing those documents later, but it does not accomplish the waiver on its own.
What Makes a Prenup Enforceable
A prenup must be in writing. Oral promises about property division are not enforceable. Both parties sign, and most states require either notarization or independent witnesses to verify the signatures. The model act does not require notarization, and many states treat it as optional unless the contract transfers real estate.
Signing with a wet-ink signature is the safer approach. The federal Electronic Signatures in Global and National Commerce Act, which generally gives electronic signatures the same force as handwritten ones, excludes contracts governed by state rules on “adoption, divorce, or other matters of family law.”5Office of the Law Revision Counsel. 15 USC 7003 – Specific Exceptions Validity under electronic signature depends entirely on your state’s rules, and many states still expect handwritten signatures on these documents.6National Telecommunications and Information Administration. Electronic Signatures – A Review of the Exceptions to the Electronic Signatures in Global and National Commerce Act
Timing
No statute sets a specific deadline, but timing matters for enforceability. An agreement signed the night before the wedding, or the morning of, invites a challenge based on duress. Judges look at whether both parties had enough time to read the terms, ask questions, and consult an attorney. Finishing the agreement several weeks before the ceremony is the clearest way to show that nobody was cornered.
Full Financial Disclosure
Each party must give the other a fair and reasonable accounting of their assets and debts before signing. This usually takes the form of a financial schedule attached to the agreement listing bank accounts, retirement balances, business interests, real estate, and obligations like tax liens or judgments. The model act makes inadequate disclosure an independent ground for refusing to enforce the agreement even if every other requirement is met.1Uniform Law Commission. Premarital and Marital Agreements Act
Disclosure does not have to be perfect to the penny, but it cannot hide the ball on major assets. A spouse who conceals a significant investment account or understates the value of a business hands the other side a strong argument for voiding the contract on fraud grounds.
Independent Legal Counsel
Having each party represented by their own attorney is not technically required under the model act, but it is the single most effective way to insulate an agreement from later attack. Independent counsel shows that both people understood what they were giving up and signed anyway. When one party goes without a lawyer, courts treat the absence as a factor supporting claims of overreach or misunderstanding.
The attorney who drafts the agreement owes a duty only to their own client. If the other party arrives without a lawyer, the drafting attorney cannot give them legal advice beyond telling them to get their own representation. Attorney fees for a non-drafting spouse’s review typically run from a few hundred dollars for a straightforward document to several thousand when significant assets or complex business interests are involved.
Why Courts Throw Prenups Out
Even a properly signed, fully disclosed agreement can be unwound if a court finds it unenforceable. The grounds fall into a few categories.
- Involuntariness or duress. If one party was pressured, threatened, or given the agreement with no real chance to review it, the contract fails. The classic fact pattern is a prenup presented days before the wedding with the implicit message that the wedding is off unless the other person signs.
- Inadequate financial disclosure. Hiding assets or misrepresenting their value gives the disadvantaged spouse grounds to void the agreement.
- Unconscionability. A contract so lopsided that it shocks the conscience of the court will not survive a challenge, whether the unfairness came from how it was negotiated or from the terms themselves. Under the model act, unconscionability is measured at the time of signing, not at the time of enforcement.1Uniform Law Commission. Premarital and Marital Agreements Act
- Public assistance eligibility. A support provision will not be enforced if its effect would leave a spouse dependent on government assistance at the time of divorce.1Uniform Law Commission. Premarital and Marital Agreements Act
Courts start with a strong presumption that a prenup is enforceable. The burden falls on the challenging spouse to prove something went wrong during negotiation, disclosure, or drafting. That presumption makes it difficult to escape an agreement you simply regret, but it also means the document has to be done right the first time.
Changing a Prenup After the Wedding
A prenup is not permanent. Both spouses can amend or revoke it after the wedding, but the change has to be in writing and signed by both parties. An oral agreement to ignore the prenup will not hold up. The amendment deserves the same formality as the original: full disclosure, voluntary consent, and ideally independent counsel on each side.
An agreement created after the wedding to replace or modify the prenup is called a postnuptial agreement. Courts tend to scrutinize postnups more closely than prenups because of concern that one spouse may feel pressured during a period of marital tension. Careful documentation of the negotiation process is important.
Sunset Clauses
Some prenups include a sunset clause that sets an expiration date for the contract or for specific provisions. Common timeframes are five, ten, or twenty years of marriage, and some clauses are triggered by milestones like the birth of a child. Once the sunset takes effect, the expired provisions no longer apply and state default rules fill the gap. A sunset clause can reassure a less-wealthy spouse that the agreement has a limited shelf life, but it can also create surprises if the couple forgets it exists and divorces after it has triggered. If you include one, both spouses should know which terms expire and what default rules replace them.