What is an Ironclad Prenup? 

Jan 16, 2023 | Prenuptial Agreements

The definition of “ironclad,” according to the Merriam-Webster dictionary, is “so firm or secure as to be unbreakable.” It follows that an “ironclad prenup” is one that is so strong it cannot be “broken” or thrown out by a court. So, how do you get yourself an ironclad (i.e., unbreakable) prenup? There are three steps to follow: (1) ensure full and fair financial disclosure between you and your future spouse; (2) make sure to follow the requirements of your state for a legally valid prenup; and (3) avoid including unfair and unreasonable terms in your prenup. Keep reading to see a breakdown of each step. 

Step 1: Ensure full and fair financial disclosure

Financial disclosure is the sharing of financial information between two soon-to-be spouses in the prenup-making process. Financial disclosure is usually done by including a snapshot of all of your property, debt, businesses, and inheritances on a financial schedule and attaching it to the back of your prenup. Do not skimp on this, hence the phrase “full and fair.” Let’s put it this way; if you withhold any information here, you are looking at a potentially invalid (and not ironclad prenup). 

Why is financial disclosure so important? Because the parties are entering into the prenup and need to know “what they’re getting themselves into,” so to speak. Let’s use an example to demonstrate. Katie and Tom are getting married and going through the prenup process. Katie withholds the fact that she has $150,000 in law school debt because she’s embarrassed about it. Based on Katie’s lack of financial disclosure, Tom sees she has no debt, so they decide to share any and all debt jointly as marital/community property. Tom does this thinking that Katie has no debt… You see how this is totally unfair to Tom because he didn’t have the whole picture? 

Step 2: Follow the requirements for a legally valid prenup

What do all ironclad prenups have in common? They all follow the state requirements for prenup validity. Requirements for a legally valid prenup vary from state to state. What is required in New York may not be required in California, and vice versa. If you do not follow the state’s requirements for a valid prenup to a tee, then you put your prenup at risk of being invalidated. In other words, not following prenup validity requirements = not an ironclad prenup. 

So, what are these requirements, anyway? Great question. In general, there are some requirements that are used in numerous states. See below for some of the validity requirements you frequently see across the nation:

  • Prenup must be in writing (no verbal contracts, people!)
  • Prenup must be signed by both parties (no signatures, no contract)
  • Prenup must be notarized (this is not required in every state, but it’s smart to do it anyways. It’s easy and cheap, so why not!)
  • Prenup must be witnessed (this is much less common, but a handful of states do require that your prenup is witnessed by one or two people)
  • Prenup must be entered into voluntarily (pretty much every single state requires this, and it stands for most contracts out there. No duress, coercion, undue influence, fraud, etc., should be involved in the making of the prenup)
  • Prenup must have some level of financial disclosure involved 
  • Prenup must NOT be unconscionable (i.e., must not be extremely unfair or one-sided)
  • Prenup must NOT include unlawful terms (do not include terms that are against the law, common sense, guys!)

Again, this is just a general list of some of the requirements that exist out there. There may be more. For example, California has a unique requirement called the 7-day rule, which requires seven calendar days between the presentation of the prenup to the other spouse and the signing of the prenup. If you do not follow the 7-day rule, you do not have a valid prenup in California. This rule does not exist in other states, so as you can see, it’s very state-dependent. 

Step 3: Avoid unfair and unreasonable terms

What we’ve learned so far is that an ironclad prenup includes both full and fair financial disclosure and follows all state requirements for a valid prenup. The only missing ingredient to this ironclad prenup pie is the fairness/reasonableness part. Courts all across the country typically refer to unfairness in a prenup as unconscionability. What is considered unfair (or unconscionable) can vary slightly from state to state. Now, prenups do not need to be exactly 50/50 to be considered “fair” or “conscionable,” but they also should not be so unfair that they’re leaving one person needing public assistance while the other zips off in their Maserati. If the fairness of the prenup is ever contested by one of the spouses to the prenup, the court will ultimately have the decision to determine whether or not it’s fair. 


You are writing your life story. Get on the same page with a prenup. For love that lasts a lifetime, preparation is key. Safeguard your shared tomorrows, starting today.
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