Marriage Tax Calculator Formula & How It Works
Marriage Effect = Tax (MFJ) − [Tax (Single1) + Tax (Single2)]
- Positive result = marriage penalty (pay more as couple)
- Negative result = marriage bonus (pay less as couple)
- MFJ brackets: wider than single (no penalty at most income levels since TCJA)
- Dual-income couples with similar salaries are most likely to have a penalty
A marriage penalty occurs when a couple pays more tax filing jointly than they would filing as two singles. Under TCJA (2017), the penalty was largely eliminated for income below the top bracket. Couples most affected: similar high incomes, both near the bracket thresholds. Marriage bonus occurs when income is very unequal — the lower earner shifts some income into the lower-bracket spouse's space.