Prenup vs. No Prenup Calculator

Compare what each spouse keeps in a divorce scenario with and without a prenuptial agreement, based on your assets, income, and state property laws.

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Assets owned before marriage
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Combined savings per year during marriage
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0 if no business
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Asset Division WITH Prenup (Divorce Scenario)
$428,636 Spouse A keeps
Spouse A Keeps$428,636
Spouse B Keeps$128,588
Marital Assets (split)$150,000
A's Pre-Marital (protected)$200,000
B's Pre-Marital (protected)$50,000
Advanced Analysis

Outcome comparison across 3 divorce scenarios, state rules reference table, and sensitivity analysis by asset gap.

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Spouse A Outcome — With Prenup vs. Without (Equitable Distribution)
Short Marriage (3 yrs)
With Prenup$577,288
Without Prenup$404,750
Prenup benefit: +$172,538 for Spouse A
Mid Marriage (10 yrs)
With Prenup$788,668
Without Prenup$462,500
Prenup benefit: +$326,168 for Spouse A
Long Marriage (20 yrs)
With Prenup$1,195,989
Without Prenup$545,000
Prenup benefit: +$650,989 for Spouse A
Professional Tools

Monte Carlo divorce probability model, lifetime financial impact, estate planning interactions, and international asset protection.

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Expected Value Model — Prenup Decision
$150,579 expected value
Prenup Benefit if Divorced$537,781
Divorce Probability (10 yrs)28%
Expected Value (EV)$150,579
Prenup Cost (est.)$8,000
Net EV$142,579
ROI on Prenup Cost6622%
Expected Value at Different Divorce Probabilities
Divorce ProbabilityExpected ValueNet EV (after cost)Decision
10%$53,778$45,778Get prenup
20%$107,556$99,556Get prenup
30%$161,334$153,334Get prenup
40%$215,112$207,112Get prenup
50%$268,890$260,890Get prenup

How a Prenup Changes What You Keep in a Divorce

A prenuptial agreement's primary financial function is to override default state property division laws in case of divorce. Without a prenup, state law determines how assets are split. With a prenup, you and your spouse decide in advance — giving both parties clarity and potentially very different financial outcomes.

Two Property Division Systems

Equitable Distribution (41 states): Courts divide assets "fairly" — typically 50/50 for marital assets, but courts have discretion. Pre-marital assets are generally protected.

Community Property (9 states: CA, TX, AZ, NV, WA, ID, LA, NM, WI): All assets acquired during marriage are split 50/50. Pre-marital assets are separately owned, but appreciation may be shared.

What a Prenup Can and Cannot Do

Prenup Can Protect / Define

Pre-marital assetsYes — keep what you came with
Business interestsYes — protect your business
Inheritance rightsYes — protect expected inheritance
Debt allocationYes — assign pre-marital debt
Alimony amountYes — waive or cap spousal support
Child custody/supportNo — courts decide this
Future child supportNo — not enforceable

Frequently Asked Questions

A well-drafted, properly signed prenup with independent counsel for both parties is generally enforceable and does protect pre-marital assets. Courts can overturn prenups for: procedural issues (signed under duress, rushed), lack of full financial disclosure, unconscionable terms, or failure to follow state-specific signing requirements. In states that have adopted the Uniform Premarital Agreement Act, enforcement standards are clear and consistent.
Conventionally, prenups benefit the wealthier spouse by protecting pre-marital assets. However, well-negotiated prenups can benefit both parties. A clear financial agreement reduces ambiguity, making divorce proceedings shorter and cheaper. A prenup can also protect the lower-earning spouse by guaranteeing minimum spousal support or a defined share of marital assets, which a court might award less than expected.
Without a prenup, a business started or grown significantly during marriage can be treated as marital property and split in divorce. The non-owner spouse may receive up to 50% of the business's value, which could force a sale. Even a business started before marriage may be partially marital if its value increased significantly during the marriage. A prenup can define the business as separate property and prevent this outcome.
In most US states, a prenup can waive, limit, or cap spousal support. However, some states (including California and New York under certain conditions) will not enforce alimony waivers that would leave one spouse on public assistance, or that are deemed unconscionable given the length of the marriage. A balanced prenup might waive alimony for short marriages but guarantee some support for marriages over 10 years.
Research and therapist surveys consistently show that couples who discuss finances openly before marriage — including prenup conversations — have lower divorce rates and higher relationship satisfaction. A prenup conversation forces full financial disclosure, clarifies expectations, and demonstrates trust through transparency. The discomfort of the conversation is often less about the prenup itself and more about underlying financial anxieties that are better addressed before marriage than after.

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