Finance Maxxing
Income Tax Basics
Marriage Penalty & Bonus
Tax impact of filing jointly vs. two singles.
A marriage penalty occurs when a couple pays more tax filing jointly than they would as two single filers. A marriage bonus is the opposite.
When Does Each Occur?
| Scenario | Result |
|---|---|
| Both earn similar amounts | Penalty — income stacks into higher brackets |
| One earner much higher than other | Bonus — low earner fills lower brackets |
| Both very high earners (>$350K each) | Penalty — 37% bracket for MFJ < 2× single |
| One earner, one stay-at-home | Bonus — doubled standard deduction, wider brackets |
Key Insight
The penalty is driven by the 37% bracket threshold: $626,350 for single vs. $751,600 for MFJ (not double). This means two high-earning spouses face 37% sooner than if they filed separately.
Important: When comparing MFJ vs. Two Singles, only compare income tax (federal + state + local). FICA is per-earner regardless of filing status and should be excluded.
Sources
Related Terms
More in Income Tax Basics
Tax Brackets
Progressive rate tiers applied to taxable income.
Marginal Tax Rate
The tax rate on your next dollar of income.
Effective Tax Rate
Your average tax rate across all income.
Taxable Income
Income remaining after deductions, subject to tax.
Adjusted Gross Income (AGI)
Gross income minus above-the-line deductions.
Modified Adjusted Gross Income (MAGI)
AGI with certain deductions added back, used for eligibility tests.
Filing Status
Determines your bracket thresholds and standard deduction.
Tax Cuts and Jobs Act (TCJA)
2017 law that lowered rates and doubled the standard deduction.