Yes, a prenup can protect a future inheritance, including one you haven’t received yet and may never be able to value in advance. Most states already treat inherited assets as the separate property of the spouse who receives them, but that default protection is fragile and can vanish the moment inherited funds touch shared finances. A prenuptial agreement locks in separate-property treatment by contract, so the protection survives the ordinary mixing of money that happens in a marriage.
Why State Default Rules Aren’t Enough
When a couple divorces, courts divide marital property, which generally covers assets acquired during the marriage. Separate property stays with its owner.1Justia. Property Division Law in Divorce Inheritance falls on the separate side of that line, even if it arrives twenty years into the marriage, as long as you keep it identifiable as yours.2Justia. Inheritances Under Property Division Law
The catch is in that last clause. Separate status survives only while the inheritance stays separate. Once inherited money mixes with marital funds, courts call it commingling, and it can convert your inheritance into marital property subject to division.3Justia. Separate vs. Marital Assets Under Property Division Law – Section: When Do Commingling and Transmutation Happen?
This happens more easily than most people expect. Depositing an inherited check into the joint account that pays the mortgage and utilities is a textbook example. Within months, the inherited dollars are indistinguishable from marital dollars, and tracing them back becomes expensive and sometimes impossible.
A related concept, transmutation, occurs when a separate asset is actively converted into a marital one. Using inherited money as a down payment on a home titled in both names is a common trigger. So is paying off a joint car loan or joint credit card balance with inherited funds. A court may conclude you intended to share the asset with your spouse.3Justia. Separate vs. Marital Assets Under Property Division Law – Section: When Do Commingling and Transmutation Happen? Most inheritance-protection plans fall apart here. People inherit money intending to keep it separate, then life happens: a roof repair, a family medical bill, and the boundary quietly dissolves.
What a Prenup Locks In
A prenuptial agreement overrides those default commingling rules by contract. Rather than relying on your ability to keep every inherited dollar in a dedicated account for decades, you write a clause defining all inheritances received by either spouse, before or during the marriage, as separate property of the recipient. The clause survives even if inherited funds later flow into a joint account or a jointly titled asset.
A well-drafted clause also covers income and growth. If you inherit a stock portfolio that doubles or a rental property that produces monthly income, the prenup can state that the appreciation and earnings remain your separate property. Without that language, a divorcing spouse can argue the growth resulted from marital effort, particularly if you actively managed the assets during the marriage, and claim a share of the increase.
You don’t have to know what you’ll inherit for the clause to work. There’s no need to list a specific inheritance, its value, or even confirm you’ll receive anything. The clause describes a category of future property and assigns it to the recipient. Courts routinely enforce provisions like this because the Uniform Premarital and Marital Agreements Act, adopted in some form by a majority of states, specifically allows prenups to address “the disposition of property upon separation, marital dissolution, or death.”4Uniform Law Commission. Uniform Premarital and Marital Agreements Act
None of this is a license to get sloppy with your finances. Courts are more likely to enforce inheritance clauses when the inheriting spouse behaved consistently with the agreement’s terms. Keeping inherited assets in a separate account where practical, holding onto records of what you received and when, and documenting transfers between accounts all reinforce the agreement’s credibility if it’s ever tested.
What Makes the Prenup Actually Hold Up
An agreement thrown out during divorce litigation is worse than no agreement at all, because both spouses relied on terms that no longer apply. Enforceability turns on how the agreement was created as much as what it says.
Writing and Signing
The document must be in writing and signed by both parties before the wedding. Verbal promises don’t count. Under the Uniform Premarital and Marital Agreements Act, a signed record is enough; no exchange of money or other consideration is required.5Uniform Law Commission. Uniform Premarital and Marital Agreements Act – Section: Formation Requirements
Voluntary Consent
Both parties must sign voluntarily. A court can refuse to enforce a prenup if one spouse proves consent was involuntary or the product of duress. Presenting the agreement the night before the wedding with a sign-or-cancel ultimatum is the classic fact pattern that destroys enforceability. Give your partner time to read, ask questions, and think.6Uniform Law Commission. Uniform Premarital and Marital Agreements Act – Section: Enforcement
Financial Disclosure
Before signing, each party must receive a reasonably accurate description of the other’s property, debts, and income. Hiding or understating assets gives the other spouse grounds to challenge the entire agreement later. If one party waives full disclosure, that waiver typically must be a separate signed document made after independent legal advice.6Uniform Law Commission. Uniform Premarital and Marital Agreements Act – Section: Enforcement
Independent Legal Advice
Each party should have their own attorney. Under the updated Uniform Act, a prenup can be challenged if one party didn’t have access to independent legal representation, meaning a reasonable amount of time to find a lawyer, get advice, and consider it. If only one spouse has counsel, some states expect the represented spouse to pay for the other’s lawyer. Sharing a single attorney is a red flag courts weigh closely.6Uniform Law Commission. Uniform Premarital and Marital Agreements Act – Section: Enforcement
Unconscionability
Even a properly signed and disclosed agreement can be struck down if its terms are unconscionable, meaning so one-sided that no reasonable person would have agreed to them. Courts vary on where they draw the line, but an agreement leaving one spouse destitute or on public assistance while the other keeps everything is unlikely to survive review. The test generally looks at fairness at the time of signing, though some states also consider fairness at the time of divorce.
Already Married? A Postnup Does the Same Job
If you’re already married and expecting an inheritance, a postnuptial agreement covers the same ground as a prenup: it can designate future inheritances as separate property, address appreciation and income, and define how inherited assets will be treated if the marriage ends.
The difference is scrutiny. Courts tend to examine postnups more carefully than prenups because the dynamic between married spouses raises greater concerns about undue influence. The same enforceability standards apply, but any suggestion that one spouse pressured the other will carry more weight, so the process deserves extra care.
Pairing a Prenup With a Trust
A prenup is something you create to protect your own inheritance. The person leaving you the inheritance, typically a parent or grandparent, has a separate tool: a trust. When assets are held in a properly structured trust rather than distributed outright, the beneficiary doesn’t legally own them. With nothing to commingle, there’s less for a divorcing spouse to claim.
A spendthrift trust is the structure most commonly used for this purpose. It keeps assets under a trustee’s control, restricts the beneficiary’s ability to transfer their interest, and blocks creditors from reaching trust assets. Assets held this way are generally treated as separate property and avoid the usual commingling risks that threaten outright inheritances.
Trusts have limits. Under the Uniform Trust Code, a spendthrift provision is unenforceable against a spouse or former spouse who has a court order for support or maintenance. A court can order distributions from the trust to satisfy child support or spousal support, even with a spendthrift clause in place. The trust protects against property division claims, not support obligations.
For maximum protection, the two tools work together. The trust prevents inherited assets from becoming the beneficiary’s personal property in the first place, while the prenup provides a contractual backup for anything that does get distributed outright.
Keep the Prenup Aligned With Your Estate Plan
A prenup and a will can contradict each other if they’re drafted in isolation. A will might leave everything to a surviving spouse while a prenup keeps certain inherited assets with the inheriting spouse’s estate. When those instructions clash, the prenup generally takes precedence because it’s a binding contract between two parties, while a will is a unilateral document the author can change at any time.
That priority only holds if the prenup is enforceable. If a court finds it was signed under duress or without proper disclosure, the will’s terms govern. Whenever you sign or update a prenup, review your will and any trust documents to make sure they point in the same direction.
One area deserves specific attention: the elective share. Most states give a surviving spouse the right to claim a minimum percentage of the deceased spouse’s estate regardless of what the will says. A prenup can waive elective share rights, but the waiver must meet the same enforceability standards as any other prenup provision, and some states impose additional requirements such as notarization or a standalone waiver document.