Prenup vs Postnup Cost Comparison 2027

Prenuptial vs postnuptial agreements: cost overview

Prenuptial agreements (signed before marriage) typically cost $1,500-$10,000 per couple in 2027, depending on asset complexity. Simple prenups for couples under $500K net worth often run $1,500-$3,000. Mid-complexity prenups with business interests or trusts run $3,500-$7,500. Ultra-high-net-worth prenups with pre-IPO equity, family trusts, and offshore assets exceed $15,000-$50,000. Both spouses must retain separate attorneys for the agreement to be enforceable in most states.

Postnuptial agreements (signed after marriage) typically cost 30%-60% more than prenups in the same situation — $2,500-$15,000 for most couples. The higher cost reflects more aggressive judicial scrutiny: courts treat postnups as transactions between spouses who already owe each other fiduciary duties, requiring additional procedural protections. Some states (Ohio with limited exceptions, Iowa) restrict or do not enforce postnups at all.

Enforceability under UPAA, UPMAA, and state law

Twenty-eight states have adopted the Uniform Premarital Agreement Act (UPAA), which provides predictable enforcement. UPAA requires the agreement to be voluntary, with fair and reasonable disclosure of property and obligations (or a written waiver of disclosure). Enforcement is denied only if unconscionable at signing AND disclosure was inadequate. UPAA states include California, Texas, Florida, Virginia, New Jersey, Illinois, North Carolina, and most western states.

The newer Uniform Premarital and Marital Agreements Act (UPMAA) applies the same standards to both prenups and postnups. Only Colorado and North Dakota have adopted UPMAA so far, but it represents the future direction of the law. Non-UPAA states (New York, Pennsylvania, Massachusetts, Connecticut, others) apply common-law contract principles with stricter procedural fairness review. New York courts apply heightened scrutiny — full disclosure, independent counsel for both spouses, and 30+ days between signing and the wedding are practical necessities.

What invalidates a prenup or postnup

Common invalidation grounds across all states: (1) Lack of full asset disclosure — failing to list a bank account or business interest is the most common invalidator. (2) Coercion or duress — signing within 48 hours of the wedding date, threats of cancellation, or no opportunity to consult counsel. (3) Unconscionable terms — leaving one spouse with no support after a long marriage while the other has substantial assets. (4) No independent counsel — both spouses should have their own attorneys, ideally retained at least 30 days before signing.

Provisions that automatically void: child support waivers (child support is the child's right, not negotiable between parents), child custody pre-determinations (courts retain best-interest jurisdiction), and provisions encouraging divorce. The American Bar Association Family Law Section's "Premarital Agreement Drafting" guide and Nolo's prenup resources emphasize that the cheapest prenup is usually the most expensive — a $1,000 boilerplate prenup that fails at trial costs the protected spouse hundreds of thousands in unprotected assets.

Sources: Uniform Premarital Agreement Act (1983), Uniform Premarital and Marital Agreements Act (2012), ABA Family Law Section premarital agreement materials, nolo.com prenup state guides. Last updated: May 2026.