How Prenuptial Agreements Work and What They Legally Cover

Prenuptial Agreements Are More Common Than Most People Realize

A 2022 survey by the Harris Poll for the American Academy of Matrimonial Lawyers found that 15% of married or engaged Americans reported having a prenuptial agreement, up from roughly 3% in the early 2000s. The American Academy of Matrimonial Lawyers reported that 62% of member attorneys had seen an increase in prenuptial agreement requests between 2018 and 2023. The growth is particularly notable among younger couples, driven by longer pre-marriage periods of wealth accumulation, higher rates of student debt, and growing awareness that marital property law, without a prenup, can produce outcomes neither party anticipated or would have chosen.

A prenuptial agreement (also called a premarital agreement or antenuptial agreement) is a contract between prospective spouses executed before marriage that governs financial rights and obligations if the marriage ends by death or divorce. It does not address non-financial matters — child custody and child support cannot be contracted in advance — but it can address nearly every other aspect of how property and income will be treated during the marriage and upon its dissolution.

What Prenuptial Agreements Can and Cannot Cover

The scope of enforceable prenuptial terms is defined by state law. The Uniform Premarital Agreement Act (UPAA), adopted in some form by 28 states, provides a baseline framework. States that have not adopted the UPAA have their own statutory or common law rules.

Procedural Requirements for Enforceability

A prenuptial agreement that is not properly executed will be voided by a court — the intended protections disappear exactly when they are most needed. Courts apply heightened scrutiny to prenuptial agreements compared to ordinary commercial contracts because of the intimate relationship between the parties and the potential for overreaching.

The requirements vary by state, but common requirements under both the UPAA and state common law include: the agreement must be in writing and signed by both parties; both parties must have made full and fair financial disclosure of assets, liabilities, and income; both parties must have had a reasonable opportunity to consult with independent counsel; the agreement must not be signed under duress; and the agreement must be executed sufficiently in advance of the wedding (courts are skeptical of agreements signed in the final days before a wedding, viewing the timing as inherently coercive).

• Both spouses should have separate, independent attorneys review the agreement; having one attorney draft for both parties creates a conflict of interest that may support a later challenge
• Financial disclosure must be genuine — a schedule of assets appended to the agreement that accurately reflects net worth is the standard approach; deliberate omissions of material assets can void the agreement
• Duress challenges succeed when one party can show they had no meaningful choice but to sign — pressure combined with last-minute presentation and no time for legal review are classic duress patterns
• California requires a 7-day waiting period between presentation of the final agreement and signing; other states apply the reasonable time standard

How Courts Evaluate Prenups at Divorce

When a spouse challenges a prenuptial agreement during divorce proceedings, courts apply a two-stage analysis: procedural unconscionability (was the process fair?) and substantive unconscionability (is the outcome so one-sided that it shocks the conscience?). Meeting both tests voids the agreement; meeting only one may or may not void it depending on the state.

Time changes circumstances. Courts in many states apply a second scrutiny at the time of enforcement — asking not just whether the agreement was fair when signed but whether enforcing it now would be unconscionable given how circumstances have evolved. A waiver of spousal support signed when both parties were equally employed may look different 20 years later when one spouse sacrificed career advancement for child-rearing.

• Agreements that leave one spouse eligible for public assistance may be voided or modified in states that include a needs-based limit on support waivers
• Agreements that were fair when signed can be challenged if they were not updated to reflect major changes: dramatically increased income, children born, one spouse leaving the workforce
• An agreement that addresses a business owned before marriage may not address a new business started during the marriage — a common gap that creates disputes

Postnuptial Agreements: The Alternative for Already-Married Couples

Couples who did not execute a prenuptial agreement or who want to change existing terms can execute a postnuptial agreement after marriage. Postnuptial agreements are more difficult to enforce than prenuptial agreements in many states because courts are skeptical of agreements made by parties already in a position of trust and dependency — unlike parties entering a new relationship, married spouses may face more complex coercive dynamics.

Some states apply heightened scrutiny to postnuptial agreements, requiring a higher standard of fairness than prenuptials. California, for example, requires postnuptial agreements to comply with the same standards as prenuptial agreements, with particular attention to whether both parties had independent counsel and adequate time for review.

This article is for informational purposes only and does not constitute legal advice.