Common-Law Marriage and Taxes: Which States Recognize It and How to File

State-by-state

Which states recognize common-law marriage?

The list of states that recognize new common-law marriages is small and has been shrinking over the decades. As of early 2026, the following jurisdictions are commonly cited as recognizing new common-law marriages:

State laws change. Alabama ended new common-law marriages after January 1, 2017. Oklahoma's status has been debated in courts. New Hampshire recognizes common-law marriage only for inheritance purposes, not for tax filing. Always verify your state's current law with a legal authority.

How does the IRS determine if you are in a common-law marriage?

The IRS does not investigate your relationship independently. Instead, it looks at whether the state where you live (or where the relationship was established) considers you married. If you meet your state's criteria, you are married for all federal purposes. The IRS requires you to file using a married filing status. Filing as Single when you are legally married through common law can result in penalties and a reclassified return.

If there is a dispute (for example, after a breakup where one partner files as married and the other as single), the IRS may request documentation. Common evidence includes joint property titles, shared bank accounts, insurance beneficiary designations, affidavits from community members, and any state registration of informal marriage.

What happens when you move to a non-recognition state?

Under the Full Faith and Credit Clause of the U.S. Constitution, most states recognize a marriage that was validly established in another state. If you formed a common-law marriage in Colorado and then move to California (which does not allow new common-law marriages), California generally recognizes your existing Colorado common-law marriage as valid. You remain married for both state and federal tax purposes. The key word is "validly established" -- you must have actually met the originating state's requirements at the time the marriage was formed.

How does common-law marriage affect withholding and the W-4?

If you are in a recognized common-law marriage, your W-4 should reflect a married filing status. Select "Married filing jointly" or "Married filing separately" in Step 1(c). If both partners work, complete Step 2 for the dual-earner adjustment, just like any married couple. See W-4 Step 2 explained. The practical impact is the same as for couples with a formal marriage certificate.

What about ending a common-law marriage?

Ending a common-law marriage requires a formal legal divorce in most states, the same as ending a ceremonial marriage. Simply separating or stopping the use of a common name does not dissolve the marriage. Until the divorce is finalized, you remain married for tax purposes. After the divorce decree, you file as Single (or HOH if you qualify) based on the December 31 rule. For mid-year divorce considerations, see divorce mid-year tax filing.

What are the tax advantages and disadvantages of being in a common-law marriage?

The advantages and disadvantages are identical to a formal marriage. Common-law married couples gain access to MFJ brackets and the doubled standard deduction, all spousal credits and deductions, tax-free employer-provided spousal benefits, and Social Security spousal/survivor benefits. The potential downsides include the marriage penalty at certain income levels (see marriage tax penalty calculator), the inability to file as Single, and joint liability for tax debts on a joint return. Couples who are unsure about their common-law status should consult a family law attorney in their state, because the tax consequences of filing incorrectly in either direction can be significant.

For a complete overview of all filing status options and how to choose between them, visit the filing status decision guide and see filing status take-home pay for paycheck-level comparisons.