Wisconsin Prenuptial Agreement
Wisconsin prenuptial agreements are governed by Wisconsin Statute § 766.58 and the Button test. Courts apply dual review — unconscionability is assessed at both signing and divorce — under a disjunctive three-part standard where any one prong is sufficient to invalidate. Courts may override a support waiver only to the extent necessary to avoid public assistance eligibility, and cannot require more. One practical risk: Wisconsin courts have voided agreements where spouses commingled assets or operated businesses jointly during the marriage, treating the prenup as abandoned.
Bottom line: Wisconsin earns a C+ grade. Dual review and a disjunctive challenge standard create enforcement risk, but a capped alimony floor and a pro-enforcement track record for well-executed agreements give Wisconsin more certainty than most dual-review states. Keep assets strictly separate during the marriage. A prenup is still far better than none.
How Wisconsin's Prenup Laws Rank: C+
Wisconsin Prenup Laws: Key Statutes Explained
Wisconsin Statute § 766.58
Separate Property
All assets can remain separate property, avoiding costly divorce settlements. Joint assets and debts titled in both names are split 50/50 as marital property.
Unconscionability at Execution AND Enforcement
Wisconsin applies a dual review. Under § 766.58(6), a prenup must not be unconscionable when made, must be voluntary, and must follow fair disclosure. Separately, under § 767.61(3)(L) and the Button v. Button test, the divorce court may refuse to enforce an agreement that has become inequitable at the time of divorce due to changed circumstances — even if it was valid when signed.
Unconscionability Standard
A prenup is unenforceable if the challenging spouse proves ANY of: (1) unconscionable when made, OR (2) involuntary execution, OR (3) lack of fair financial disclosure without actual notice of the other's finances.
Public Assistance Spousal Support Floor
Spousal support can be waived entirely, but courts may override waivers if enforcement would make one spouse eligible for public assistance. Courts can require only enough support to avoid public assistance eligibility, notwithstanding the prenup.
Timing
No minimum specified, but we recommend signing the prenup at least 30-60 days before the wedding, with both parties having 2-3 weeks to review the final version to minimize challenge risk.
Independent Counsel
Not required, but separate counsel dramatically strengthens enforceability if the agreement is later challenged.
Financial Disclosure
"Fair and reasonable disclosure" of property and financial obligations required, statute does not address if written waiver is acceptable (PerfectPrenup includes both out of precaution).
Medium Burden to Challenge
Challenging party must prove the prenup is invalid by preponderance of evidence (standard civil burden, not clear and convincing).
Child Support and Custody
Child support and custody clauses are unenforceable and could undermine the entire agreement. Do not include.
Wisconsin Prenuptial Agreement Court Cases
Wisconsin's biggest weakness is where married couples operate a business together. To avoid equal division when one party provides minimal contributions, a contract should be drawn outlining responsibilities and ownership percentage.
Brandt v. Brandt, 145 Wis. 2d 394, 427 N.W.2d 126 (Ct. App. 1988)
The court declined to enforce a postnuptial agreement where the parties completely ignored it throughout the marriage and commingled their assets so thoroughly that meaningful enforcement was impossible.
Krejci v. Krejci, 2003 WI App 160, 266 Wis. 2d 284, 667 N.W.2d 780 (2003)
The court refused to enforce a prenuptial agreement excluding an inherited resort from the marital estate because the parties operated it as a partnership for 18 years, never discussed the agreement during the marriage, commingled their finances, and both spouses' efforts contributed to the resort's appreciation in value.
Steinmann v. Steinmann, 309 Wis. 2d 29, 749 N.W.2d 145, 2008 WI 43 (2008)
The court held that when separate property is used to purchase property that is then titled jointly, this demonstrates donative intent and transmutes the property from individual to marital property, resulting in Rose being ordered to pay Tony $764,000 for his share of their $2.2 million Lake Geneva home despite it being purchased partially with her individual settlement funds.
Button v. Button, 131 Wis. 2d 84, 388 N.W.2d 546 (1986)
The Wisconsin Supreme Court reversed the circuit court's enforcement of a 1974 postnuptial agreement and established the foundational "Button test" requiring prenuptial agreements to satisfy three requirements: fair and reasonable financial disclosure, voluntary and free entry, and substantive fairness both at execution and at enforcement.
Gardner v. Gardner, 190 Wis. 2d 216, 527 N.W.2d 701 (Ct. App. 1994)
The court upheld a prenuptial agreement giving the husband (who had over $3 million in assets) substantially all marital property, finding that five days' notice before the wedding was adequate when the wife had independent counsel, and that disparity in property division alone does not make an agreement unfair.
Greenwald v. Greenwald, 154 Wis. 2d 767, 454 N.W.2d 34 (Ct. App. 1990)
The court enforced a premarital agreement between a retired 70-year-old widower and his former housekeeper, holding that if a party's conduct demonstrates that specific knowledge of the other party's property and finances is not important to them, the agreement may not be defective even without formal financial disclosure.
5-Step Checklist: How to Sign & Execute a Prenup in Wisconsin
Step 1: Download and read the Wisconsin prenuptial agreement
Start with our free template. It is written for Wisconsin-specific statutes and case law under Wis. Stat. § 766.58 and the Button v. Button three-part enforceability test. Read it in full — know what you are getting into legally with marriage. The 15+ pages is written thoroughly to include rebuttals to common legal challenges and fallback provisions.
Step 2: Draft changes on your own
See a clause you don't like? Copy it into an AI like Claude, explain what you'd like to change or what you want the clause "to do." Save any changes as a separate alternate version — don't overwrite the original. Bring both versions to your attorney review. Note: AI is often gender-biased and crafts terms beyond what is legally required. Push back on its output.
Step 3: Find a lawyer in your state
Find a matrimonial or divorce attorney in your state. Avvo, Findlaw, and Justia are good. Look for someone with 10+ years experience. Call or email and ask them how much to review your draft prenup and help with signing. Send them your draft.
Step 4: Meet your lawyer 4–6 months before the wedding
Our recommendation: sign the prenup before proposing. That way, you both get the legal work out of the way, and you know this is the right person to marry. Already proposed? 4–6 months before the wedding should leave you enough time to give your spouse 2 weeks to review the final draft and have it signed 60+ days before the wedding. Wisconsin has no statutory minimum timing, but courts weigh adequate review time as a Button voluntariness factor. Gardner upheld a five-days-before signing when the wife had independent counsel; Matson-style last-minute ambushes without attorney access create real challenge risk.
Step 5: Sign with your attorneys and store the agreement
Execute the agreement with both attorneys present — independent counsel is "the best evidence" of voluntary, knowing execution under the Button test. No attorneys? Use a standalone notary at minimum. Each party keeps a signed original, and so should each party's attorney. Store yours somewhere secure like a safety deposit box. Create a .pdf and save it via a backup drive and email.
Wisconsin Prenuptial Agreement: Frequently Asked Questions (2026)
1. What happens if you get divorced in Wisconsin without a prenup?
Wisconsin is one of only nine marital property (community property) states. Without a prenuptial agreement, nearly everything earned or acquired during the marriage is presumed marital property owned 50/50 — regardless of who earned it or whose name is on the account. Under § 767.61, the court starts with an equal division and departs from it only if the result would be inequitable. Property you owned before the marriage or received by gift or inheritance can remain separate, but only if you kept it completely segregated from joint accounts and marital funds. If you commingled it — even once — it may lose its exempt status.
2. Is a "marital property agreement" the same as a prenuptial agreement in Wisconsin?
Yes. Wisconsin's statute (§ 766.58) uses the term "marital property agreement" rather than "prenuptial agreement." They are legally identical. If signed before the wedding, it takes effect upon marriage. If signed during marriage, it functions as a postnuptial agreement. Both are governed by the same statute and the same enforceability standards. You may see Wisconsin courts and lawyers use "MPA," "premarital agreement," or "antenuptial agreement" interchangeably.
3. Can a Wisconsin prenup override the state's community property rules?
Yes — that is its primary purpose. Wisconsin's default marital property rules classify most assets acquired during marriage as 50/50 marital property. A prenuptial agreement under § 766.58 allows couples to reclassify property, keeping specified assets as individual property rather than marital property. You can also designate how income, appreciation, and future acquisitions will be classified. Without the agreement, the community property default controls.
4. Are prenuptial agreements enforceable in Wisconsin?
Generally yes, and they are presumed equitable. Wisconsin applies two separate legal tests. First, under § 766.58(6), a prenup is unenforceable if it was unconscionable when signed, was not voluntary, or lacked fair financial disclosure. Second, at divorce under § 767.61(3)(L), the court may independently refuse to enforce an agreement it finds inequitable at that time — for example, if significantly changed circumstances make the original terms unfair. A well-drafted agreement with full disclosure, voluntary execution, and substantively reasonable terms will survive both tests.
5. What are the legal requirements for a valid prenup in Wisconsin?
The agreement must be (1) in writing, (2) signed by both spouses, and (3) supported by fair and reasonable financial disclosure. Notarization is not statutorily required but is strongly recommended. Independent legal counsel for each party is not required but dramatically strengthens enforceability if the agreement is later challenged. The agreement cannot adversely affect a child's right to support. It takes effect only upon marriage.
6. How far before the wedding should you sign a prenup in Wisconsin?
Wisconsin's statute does not impose a minimum waiting period. However, signing too close to the wedding invites a duress or involuntariness challenge. We recommend having a final signed agreement at least 30–60 days before the wedding, with each party having had 2–3 weeks to review the final version with independent counsel. In Gardner v. Gardner, the court upheld a prenup where the final draft was delivered five days before the wedding — but only because the wife had been negotiating with her own attorney for months. Relying on that kind of fact pattern is a risk, not a strategy.
7. Do you need a lawyer for a prenuptial agreement in Wisconsin?
Not legally required, but strongly advisable. Wisconsin courts have held that one attorney representing both parties does not by itself make a prenup unconscionable (§ 766.58(8)). However, separate counsel for each party is the single strongest enforceability safeguard. A court is far less likely to find involuntariness, lack of understanding, or procedural unfairness when both parties had independent legal advice. For a DIY agreement, the risk is not that it's automatically invalid — it's that a motivated challenger will have an easier path to invalidation.
8. What financial disclosure is required for a Wisconsin prenup?
Section 766.58(6)(c) requires "fair and reasonable disclosure, under the circumstances, of the other spouse's property or financial obligations." Both parties must also either have actual notice of each other's finances, or receive formal disclosure. The statute does not specify a particular format, nor does it explicitly allow a written waiver of disclosure (unlike some states' UPAA versions). We recommend written disclosure schedules listing all assets, liabilities, and income — attached as exhibits and signed by both parties — plus a general waiver as a precaution.
9. Can you waive alimony in a Wisconsin prenup?
Yes, with limits. Section 766.58(3)(d) permits modification or elimination of spousal support. But two statutory floors apply: (1) during the marriage, support cannot be reduced below "necessary and adequate" levels under § 766.58(9)(a); and (2) at divorce, courts may override a waiver if enforcement would make one spouse eligible for public assistance under § 766.58(9)(b). The court will also independently evaluate fairness at divorce under § 767.61(3)(L). A total waiver is more likely to survive if both spouses have independent earning capacity and the agreement includes a clear acknowledgment that each party understands the waiver.
10. How does a prenup protect a business in Wisconsin?
A prenuptial agreement can classify a business and its appreciation as the owner-spouse's individual property, keeping it outside the marital estate. This is critical in Wisconsin, where the marital property default would otherwise give the non-owner spouse a 50% interest in business value accrued during the marriage. The agreement should address not just ownership, but also business income, goodwill, and appreciation. Be warned: if both spouses actively operate the business together, the Krejci v. Krejci line of cases shows that courts may refuse to enforce the agreement if the parties' conduct effectively abandoned it.
11. Can a Wisconsin prenup protect a family farm?
Yes, and for Wisconsin families this is one of the most important uses of a prenuptial agreement. Farmland, equipment, livestock, and operating entities can be classified as individual property. However, farms present unique commingling risks: if both spouses work the operation, contribute labor, or deposit farm income into joint accounts, the prenup's protections can erode — exactly what happened in Brandt and Krejci. The agreement should include clear operating boundaries, specify that farm income remains individual property, and prohibit joint titling of farm assets without a written amendment.
12. How does a prenup protect inheritance and children from a prior marriage in Wisconsin?
A prenuptial agreement can waive each spouse's elective share rights against the other's estate, direct that inherited assets remain individual property, and ensure that specified assets pass to children from a prior relationship rather than a new spouse. Without a prenup, Wisconsin's elective share statute gives a surviving spouse the right to claim a portion of the deceased spouse's estate — potentially overriding your will or trust. For second marriages, a prenup is the single most effective tool for keeping estate plans intact.
13. What is commingling, and why does it matter for a Wisconsin prenup?
Commingling is mixing separate property with marital property — for example, depositing an inheritance into a joint bank account. In Wisconsin's marital property system, commingled assets can lose their individual classification and become divisible marital property. Courts in Brandt v. Brandt and Krejci v. Krejci refused to enforce agreements where the parties had so thoroughly mixed their finances that tracing individual assets was impossible. A prenup sets the rules, but you must actually follow them: maintain separate accounts, avoid joint titling of individual assets, and document any transfers between individual and marital property.
14. How much does a prenuptial agreement cost in Wisconsin?
Attorney fees for a straightforward Wisconsin prenup typically range from $500 to $2,500 per spouse. Complex agreements involving businesses, farms, multiple properties, or blended families can run $3,000 to $5,000+ per spouse. Each party should budget for their own attorney. A flat-fee arrangement for drafting starts around $690 on average; review-only engagements average around $340–$400. Online templates are cheaper but carry meaningful enforceability risk, particularly in Wisconsin where courts examine disclosure and voluntariness closely.