Tax Filing After Divorce in Wisconsin

The year you divorce in Wisconsin is the most complicated tax year you will file. Your marital status on December 31 determines your filing status for the entire year — not the date the divorce was finalized. If the judge signs your decree on December 30, you file as Single or Head of Household for all twelve months. If the decree comes through on January 2, you were technically married for the entire prior tax year and could still file jointly for that year.

On top of the federal rules, Wisconsin adds its own layer of complexity through Publication 113 and the marital property income reporting requirements.

Federal Filing Status

Single: If your divorce was final by December 31, you file as Single (or Head of Household if you maintained a home for a dependent child for more than half the year).

Married Filing Jointly or Separately: If you were still legally married on December 31 — even if the divorce was pending — you can file a joint return (if both spouses agree) or file Married Filing Separately. Married Filing Separately is often more expensive due to reduced deductions and credits, but it eliminates joint-and-several liability for your spouse's tax obligations.

Wisconsin Publication 113 and Marital Property Income

Wisconsin is a marital property state, which creates a unique reporting requirement. During the months of the year you were married, each spouse is presumed to have earned half of the other's income (and be liable for half of certain deductions). Wisconsin Department of Revenue Publication 113 explains how to allocate income and deductions between spouses for the portion of the year the marriage existed.

Schedule M is used to adjust your Wisconsin return for marital property income allocation. If you were married for only part of the year, Schedule M apportions income between the marital period and the post-divorce period. This is where most people get confused or make errors.

An Income Reclassification Agreement is an option if both ex-spouses agree on how to allocate income for the year. This agreement simplifies filing by establishing a mutually accepted allocation rather than relying on the default Publication 113 formulas.

Update Your Withholding Immediately

The day your divorce is final, submit updated withholding forms to your employer:

• Form W-4 (federal): Change your filing status from Married to Single or Head of Household. Adjust your withholding based on your new single income.
• Form WT-4 (Wisconsin): Same adjustment for state withholding.

If you wait until the next tax season to address your withholding, you will have missed the chance to adjust withholding for the rest of the year. Your employer cannot retroactively fix earlier withholding — review your projected tax and adjust future withholding as needed.

Child-Related Tax Benefits

If you have children, the decree or custody agreement typically specifies which parent claims the child as a dependent. Under federal rules, the custodial parent claims the dependency exemption by default. If the non-custodial parent is to claim the child, the custodial parent must sign IRS Form 8332 (Release/Revocation of Release of Claim to Exemption for Child by Custodial Parent).

Do not double-claim. If both parents claim the same child, the IRS may reject one of the claims and require you to substantiate which parent is entitled to claim the child.

The Wisconsin After-Divorce Checklist includes a tax season section with a Publication 113 walkthrough, a withholding adjustment calculator, and the key dates and forms you need for the year-of-divorce return.

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