TL;DR: A prenup is not permanent once signed. Under Section 5 of the Uniform Premarital Agreement Act, adopted by most states, a prenup can be amended or revoked after marriage through a written agreement both spouses sign. About 20 percent of married couples report having a prenup, but that figure more than doubles for younger generations (First, 2026 ), and many will want a way to revisit it as life changes.
You heard someone call a prenup a "living document," and then someone else told you it's "set in stone." Both can't be right, and the mixed messaging is confusing, especially if you already signed one or are deciding whether to. Here is where things land: a prenup can change after you marry, but only when both of you agree and put it in writing. That distinction matters, and it is the reason younger couples increasingly see a prenup as something they can grow with. About 20 percent of married couples report having a prenup, and that share more than doubles for younger generations, according to First's Prenup Report (2026) , which cites a 2023 Harris Poll finding 41 percent of engaged or married Gen Z adults and 47 percent of millennials report having one.
What people mean by "living document"
When someone calls a prenup a living document, they usually mean it can evolve alongside your marriage. That idea is useful, and it is mostly accurate. A prenup written before a couple buys a home, starts a company, or has a child does not have to stay frozen at the moment of signing.
What the phrase does not mean is that a prenup updates itself. It will not adjust silently when your finances shift, and one spouse cannot quietly rewrite it. Changes happen on purpose, through formal steps, with both people involved. If you are new to all of this, our prenup primer walks through the basics, and if you do not have a prenup yet, this guide is a good starting point.
A prenup can change, but only on purpose
Here is the reassuring part. A signed prenup is not a life sentence. Most states follow the Uniform Premarital Agreement Act, and under Section 5 of the UPAA , after marriage a premarital agreement may be amended or revoked only by a written agreement signed by both parties. The same section adds a helpful detail: that amendment or revocation is enforceable without consideration, meaning neither spouse has to give the other something of value in exchange for the change.
The key word is "only." A prenup cannot be changed by a verbal promise, a text thread, or an unspoken understanding. It cannot be changed by one spouse acting alone. No silent edits, no one-sided changes, no surprises. Both of you have to agree, in writing, with signatures.
How couples amend or revoke a prenup after marriage
The mechanism is straightforward once you know it. To amend a prenup, you and your spouse put the change in writing and both sign it. To revoke it entirely, you do the same thing: a written agreement, signed by both of you, stating that the original prenup no longer applies.
One point trips people up. Destroying the original document does not legally revoke it. As the NAEPC Journal explains in its review of the uniform act , revocation has to be done through a signed writing; tearing up or shredding the paper accomplishes nothing on its own.
States that have adopted the UPAA codify this same rule. In California, Family Code Section 1614 provides that after marriage a premarital agreement may be amended or revoked only by a written agreement signed by the parties. Nevada follows suit under Revised Statutes Section 123A.070 . The wording is nearly identical from state to state, which is part of why the rule is reliable. Before you draft any change, our prenup checklist covers the financial documents both spouses should gather, since full disclosure matters as much for an amendment as it did for the original.
Common reasons couples revisit a prenup
Life rarely stays still after the wedding, and certain changes tend to prompt a second look. A spouse starts a business and wants to address how it is treated. A child arrives and the couple rethinks long-term planning. An inheritance comes in. One partner shifts careers, and the income picture that shaped the original agreement looks different now.
None of these are signs of trouble. They are ordinary milestones, and revisiting your prenup when they happen is good planning. If your circumstances have shifted, our post on what happens when things change after your prenup goes deeper on how to think it through. The point is that the option exists, and using it is a way of keeping your agreement aligned with your actual life.
Amending a prenup vs. signing a postnup
Once you are married, you cannot make a new prenup. By definition, a prenup is signed before the wedding. What you can do is amend the existing one or sign a postnuptial agreement, which is a separate contract created during the marriage.
The two paths serve different situations. Amending works well when you want to refine or correct an existing prenup. A postnup comes into play when no prenup exists, or when you want a larger rework. Both require mutual consent and full financial disclosure, and enforceability of postnups varies by state, with some courts applying heightened scrutiny. For a major rework, many couples consult independent legal counsel about a postnuptial agreement.
Question
Amend the existing prenup
Postnuptial agreement
When it's used
Refining or correcting an existing prenup
No prenup exists, or a major rework is wanted
What it is
A written addition or change to the original prenup
A separate contract signed during marriage
Requires both signatures
Yes
Yes
Requires financial disclosure
Yes (best practice)
Yes
Can one spouse do it alone
No
No
Independent legal review
Strongly recommended
Strongly recommended; required in some states for certain terms
Frequently Asked Questions
Can a prenup be changed after marriage?
Yes. In most states, which follow the Uniform Premarital Agreement Act, a prenup can be amended after marriage. The change must be put in writing and signed by both spouses. One spouse cannot change it alone, and an informal agreement or verbal understanding will not hold up.
Can you cancel or revoke a prenup once you're married?
Yes. Under the Uniform Premarital Agreement Act, a prenup can be revoked after marriage by a written agreement signed by both parties. Both spouses must agree to cancel it. Simply tearing up the original document does not legally revoke it.
Is a prenup really a "living document"?
In a sense, yes. A prenup can evolve as your life changes through formal amendments. But "living document" does not mean it updates automatically or informally. Every change requires the same care as the original: a written agreement, both signatures, and ideally independent legal review.
What's the difference between amending a prenup and getting a postnup?
Amending a prenup changes the existing agreement through a written, signed addition. A postnuptial agreement is a separate contract created during the marriage. Both require mutual consent and full financial disclosure. If you want a major rework, many couples consult independent counsel about a postnuptial agreement.
Can I make a prenup after I'm already married?
No. By definition, a prenup is signed before marriage. If you are already married, you cannot create one. Instead, you can amend an existing prenup or consult independent legal counsel about a postnuptial agreement, which serves a similar purpose during the marriage.
Do both spouses have to agree to change a prenup?
Yes. A prenup cannot be amended or revoked by one spouse alone. Both parties must voluntarily agree and sign the written change. This mutual-consent requirement is part of what keeps the agreement fair and enforceable when circumstances shift.
Thinking about your prenup as part of an ongoing plan
A prenup works best when it reflects the life you are living, not the one you had on your wedding day. Treating it as something you can revisit, together and in writing, takes the pressure off getting every detail perfect up front. You set the terms now, with full information and time to decide, knowing the door stays open if circumstances change.
If you and your partner want a prenup you can revisit as life changes, First lets you create one fully online , with independent attorney review available. State rules vary, so confirm your own state's requirements before finalizing any amendment or revocation, and consider independent legal review for any change you make.
First is not a law firm. The information and tools provided by First on this site are not legal advice and not a substitute for the advice of an attorney.
Methodology
These figures are drawn from First's Prenup Report (2026), which cites a 2023 Harris Poll on prenup prevalence by generation. The legal mechanism is drawn from Section 5 of the Uniform Premarital Agreement Act and its state codifications, for example California Family Code Section 1614, covering the rule that a prenup may be amended or revoked after marriage only by a written agreement signed by both parties.
Sources
