Without a prenuptial agreement, your state legislature has already written one for you. The default rules that kick in when you marry without a prenup control how property and debt get divided if you divorce, whether either spouse pays alimony, and what a surviving spouse inherits when the other dies. Those rules apply the same way to every couple in the state, regardless of what either of you would have chosen for yourselves.
Here is what those defaults actually require.
Your Property Gets Sorted Into Two Buckets
Before anything can be divided, a court sorts every asset and debt into separate property or marital property. Separate property is generally what you owned before the wedding, plus gifts and inheritances received in your name alone during the marriage. Marital property covers almost everything else acquired between the wedding and the divorce filing, no matter whose name is on the title or account.
Only marital property goes into the pot for division. Your separate property usually stays yours, but it can lose that protection through commingling. Deposit an inheritance into a joint checking account, use premarital savings for a down payment on the family home, or let your spouse actively manage a business you brought into the marriage, and the line between “mine” and “ours” blurs. Courts require detailed records to trace the original separate contribution back through years of mixed transactions. If you cannot trace it, the asset is treated as marital property.
Which Division Rule Applies Depends on Your State
Community Property States: 50/50 by Default
Nine states use community property: Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, Washington, and Wisconsin. In these states, virtually all income earned and property acquired during the marriage belongs to both spouses equally. Debts incurred during the marriage are shared the same way. The credit card balance one spouse ran up, the car loan, the mortgage — all of it is presumed to be a joint obligation split down the middle.
Judges in community property states generally have little room to adjust the split based on who earned more, who spent more wisely, or who caused the marriage to fail. The result is mathematically clean but can feel harsh, especially when one spouse managed all the finances while the other had no idea what debts were accumulating.
Equitable Distribution States: Fair, Not Equal
The remaining 41 states follow equitable distribution. Instead of splitting everything in half, judges weigh factors to decide what is fair. Those factors typically include the length of the marriage, each spouse’s age and health, earning capacity, contributions to the household (including unpaid caregiving), and the financial circumstances each person will face after the divorce.
A spouse who left the workforce for a decade to raise children might receive a larger share of the assets to offset diminished earning power. A spouse who dissipated marital funds through gambling or reckless spending might receive less. Debts follow a similar analysis: the person better positioned to pay, or the one who benefited most from the borrowing, may absorb a larger portion. Two families with identical finances can get different outcomes depending on the judge, the arguments, and the facts presented.
Growth on Separate Property Can Become Marital
Equitable distribution gets particularly complicated when separate property grows during the marriage. Courts distinguish between passive appreciation driven by market forces, inflation, or general economic conditions, and active appreciation driven by a spouse’s labor, management, or investment decisions. If you owned a rental property before the marriage and its value rose simply because real estate prices climbed, that increase is typically passive and stays separate. If you or your spouse spent years renovating the property, managing tenants, and reinvesting rental income, courts will likely treat some or all of that growth as marital property.
The same logic applies to investment portfolios, businesses, and professional practices. Quantifying how much growth came from market forces versus spousal effort often requires hiring a valuation professional, which adds cost to an already expensive process.
Businesses and Retirement Accounts Need Special Handling
A business started or grown during the marriage is marital property in most states, and it presents some of the hardest valuation problems in divorce. Courts typically rely on income-based approaches that project future earnings, asset-based methods that tally what the business owns, or market comparisons that look at what similar businesses have sold for. Each method can produce wildly different numbers, and both sides will usually hire their own experts.
Retirement accounts are often the largest marital asset after the family home. Federal law protects pension and 401(k) benefits from being assigned to anyone other than the plan participant, with one exception: a qualified domestic relations order, or QDRO, is a court order that directs a retirement plan to pay a portion of one spouse’s benefits to the other as part of a divorce settlement.1Office of the Law Revision Counsel. United States Code Title 29 – 1056 Form and Payment of Benefits Without a QDRO, the plan administrator has no legal basis to split the account. When a spouse or former spouse receives a distribution under a QDRO, they report it as their own income and can roll it into their own retirement account to avoid immediate taxation.2Internal Revenue Service. Retirement Topics – QDRO Qualified Domestic Relations Order
Spousal Support Follows Statutory Formulas
Without a prenup setting terms, alimony follows your state’s statutory framework. Most states have adopted standards influenced by the Uniform Marriage and Divorce Act, which allows courts to award maintenance when the requesting spouse lacks enough property to cover reasonable needs and cannot become self-supporting through appropriate employment. The amount and length of payments hinge on the standard of living during the marriage, how long the marriage lasted, and how much time and money the lower-earning spouse would need to gain education or job skills to become financially independent.
Courts do not just take a spouse’s word that they cannot find work. When someone is voluntarily unemployed or underemployed, judges can impute income, assigning an earning capacity based on the person’s education, work history, skills, age, health, and the local job market. If you quit your job right before a divorce hoping to maximize your support award, the court will likely calculate payments as though you are still earning what you are capable of earning.
When Support Ends or Changes
Spousal support orders are not permanent in most cases. The most common automatic termination events are the recipient’s remarriage and the death of either party. Beyond those triggers, either side can ask the court to modify or end payments by showing a material change in circumstances, such as a significant income increase for the recipient, a job loss for the payer, or a serious health change. Many states also allow courts to reduce support when the recipient moves in with a new partner, on the presumption that shared living expenses reduce financial need.
The Tax Rules You Inherit by Default
Alimony Is No Longer Deductible
For any divorce or separation agreement finalized after 2018, alimony payments are not deductible by the person paying and not taxable income for the person receiving them.3Internal Revenue Service. Topic No. 452, Alimony and Separate Maintenance This was a major shift from the old rules, where the payer could deduct alimony and the recipient owed income tax on it. The change means the payer shoulders a higher after-tax cost, which often reduces the total amount that courts award. If your agreement was finalized before 2019, the old deduction rules still apply unless you later modified the agreement and the modification specifically adopted the new rules.
You Inherit the Original Cost Basis on Property
When you transfer property to a spouse or former spouse as part of a divorce, no one owes tax on the transfer itself. Federal law treats it as a gift for tax purposes, meaning the recipient takes over the transferor’s original cost basis rather than receiving a stepped-up basis at current market value.4Office of the Law Revision Counsel. United States Code Title 26 – 1041 Transfers of Property Between Spouses or Incident to Divorce The transfer must occur within one year of the divorce or be related to the end of the marriage under the terms of a divorce instrument, with a six-year outer limit.5Internal Revenue Service. Publication 504 Divorced or Separated Individuals
The basis carryover is where people get burned. Say the family home was purchased for $250,000 and is now worth $700,000. If you receive the house in the divorce, your cost basis remains $250,000. When you eventually sell, you will owe capital gains tax on the difference between the sale price and that $250,000 basis, minus any applicable exclusion. An asset that looks like it is worth $700,000 on paper might net you considerably less after taxes.
Your Spouse Has Automatic Inheritance Rights
The absence of a prenup matters outside of divorce too. When a spouse dies, state law gives the surviving spouse guaranteed inheritance rights that can override what a will says, or fill the gap entirely when there is no will.
Dying Without a Will
If your spouse dies without a will, intestate succession laws determine who inherits. Every state gives the surviving spouse priority, though the exact share varies depending on whether the deceased had children, parents, or other close relatives. In many states, the surviving spouse inherits the entire estate if there are no children, or if all the children are also children of the surviving spouse. When the deceased had children from a prior relationship, the surviving spouse’s share typically shrinks to make room for those children’s inheritance.
The Elective Share Overrides a Will
Even when a will exists, most states give the surviving spouse the right to reject whatever the will provides and instead claim an elective share of the estate. The percentage varies by state but often ranges from one-third to one-half. Under the Uniform Probate Code, which many states have adopted in some form, the elective share scales with the length of the marriage, starting at zero for marriages under one year and reaching 50 percent of the marital-property portion of the augmented estate at 15 years or more.
The augmented estate concept prevents an end-run around the elective share. Without it, a spouse could transfer most of their wealth into trusts, joint accounts with other people, or payable-on-death designations during their lifetime, leaving almost nothing in the probate estate. The augmented estate pulls those nonprobate transfers back into the calculation.
A Divorce Decree Does Not Bind Your Creditors
This is the gap most people do not see coming. A divorce decree can assign a joint credit card balance entirely to your ex-spouse. It can order them to pay the remaining car loan. But the decree is an agreement between the two of you, enforced by the family court. It does not change your contract with the lender. If your name is on a joint debt and your ex-spouse stops paying, or files for bankruptcy, the creditor can come after you for the full amount.6United States Bankruptcy Court for the District of Oregon. My Ex-Spouse Has Filed Bankruptcy
Your remedy at that point is going back to family court to enforce the original decree against your ex. You will still owe the creditor in the meantime, and the damage to your credit score is already done. This is why experienced divorce attorneys push to refinance or close joint accounts before or immediately after the decree is finalized, rather than relying on the other spouse’s promise to pay.
What a Prenup Could Have Changed
A prenuptial agreement can override nearly every default rule described here. It can designate specific assets as separate property regardless of commingling, set a predetermined formula for dividing property, cap or waive spousal support, protect a business from valuation disputes, and modify or waive the elective share for inheritance purposes. What it cannot do is predetermine child custody or child support. Courts retain authority over children’s welfare and will not enforce agreements that attempt to settle those issues in advance.
Skipping a prenup does not mean you have no agreement. You have one. It was written by your state legislature, and it applies the same way to every marriage regardless of circumstances. For couples with roughly equal income and few assets, those defaults may work fine. For everyone else, knowing exactly what the defaults require is the first step toward deciding whether to live with them.