Is Your Prenup Actually Enforceable? What Couples in California Need to Know

You've seen it in the headlines. A celebrity couple splits, one spouse tries to invoke the prenuptial agreement, and suddenly there's a court battle over whether the thing is even valid. How does a legally signed document end up worthless?

The short answer: prenups can be thrown out. If you're considering a prenuptial agreement (or already have one), here's what actually determines whether it will hold up.

The good news is that California law favors prenuptial agreements — meaning courts start with a general presumption that they should be enforced. The bad news is that there are several specific ways an agreement can be invalidated, and some of them are surprisingly easy to trigger.

In California, the rules for prenups signed after January 1, 2002 are governed by the California Premarital Agreement Act. Under the Act, a prenup will be unenforceable if: it wasn't made voluntarily, it's unconscionable and proper financial disclosures weren't made, or it violates public policy. Let's break each of those down.

The Agreement Must Be Truly Voluntary

Under California law, a premarital agreement is presumed to have been signed involuntarily unless four specific conditions are met:

1. Each party had independent legal counsel — or formally waived it. This means your own attorney, not one suggested or paid for by your partner. If your fiancé recommended a specific attorney for you to use, that could raise red flags. If one person is paying both attorneys' fees, that's also a problem. The safest approach: each person hires their own lawyer independently.

If you chose to waive counsel entirely, that waiver must be in a separate document — it cannot simply be buried inside the prenup itself.

2. There was a seven-day waiting period. You cannot be handed a prenup and asked to sign it the same week — or even a few days later. California requires at least seven calendar days between when you're first presented with the agreement and when you sign it. Springing a prenup on someone the week before the wedding is a classic way to get it thrown out later.

3. You had the legal capacity to sign. You must have been of sound mind when you signed. Signing under the influence of substances, during a mental health crisis, or in any other impaired state can invalidate the agreement.

4. No fraud, duress, or undue influence. This is more nuanced than it might sound. Duress means being threatened — someone fearing for their safety, family, or financial security if they don't sign. Undue influence means someone took unfair advantage of your vulnerabilities or pressured you in a way that overrode your free will.

Importantly, persuasion and negotiation are not undue influence. Neither is the fact that one person really, really wanted to get married. But a history of domestic violence, threats to call off the wedding, or exploiting someone's financial desperation can all tip the scales toward invalidation.