Whether marriage raises or lowers a couple’s combined tax bill depends entirely on how their two incomes compare to each other — there’s no universal answer.
How it works
The same combined income is taxed twice: once under joint brackets, once as two separate single filers under single brackets. The difference reveals whether marriage costs or saves this specific couple money at these specific incomes.
What this does not include
This year’s federal brackets happen to make MFJ exactly double the single brackets at every threshold, which means two equal earners see neither a penalty nor a bonus under current law — that relationship isn’t guaranteed to hold after future inflation adjustments or law changes, so this calculator should be re-run against the actual current-year brackets rather than assumed to always net to zero for equal earners.
How to use this calculator
- Enter each spouse’s individual taxable income.
Frequently asked questions
When does a marriage penalty happen?
Most commonly when both spouses have similar, moderately high incomes — combining two similar incomes can push more of the combined total into higher brackets than either would face filing separately as singles.
When does a marriage bonus happen?
Most commonly when one spouse earns much more than the other — the lower earner’s unused low brackets absorb part of the higher earner’s income on the joint return.
Does this account for state taxes?
No — this is federal only; state tax treatment of marriage varies significantly and isn’t modeled here.
