Marriage Penalty
When a married couple pays more combined income tax filing jointly than they would have paid as two single filers.
What is Marriage Penalty?
The marriage penalty occurs when two individuals pay more combined federal income tax by filing as married filing jointly (MFJ) than they would have paid filing separately as two single taxpayers. It arises because certain tax brackets for married couples are not exactly double those for single filers — particularly in higher income brackets — causing high-earning dual-income couples to be pushed into higher marginal rates. The Tax Cuts and Jobs Act of 2017 reduced the marriage penalty for most brackets by doubling the income thresholds for married filers, but it persists at higher income levels and for certain provisions including the Net Investment Income Tax, Social Security taxation thresholds, and IRMAA Medicare surcharges.
Example
Two individuals each earning $200,000 would each file as single in the 32% bracket. After marrying, their combined $400,000 income filed jointly pushes a portion into the 35% bracket — which begins at $383,900 for MFJ in 2024 but at $243,700 for single filers — resulting in a higher combined tax bill than if they had remained single.
Source: IRS — Publication 505: Tax Withholding and Estimated Tax