Marriage affects taxes in ways that surprise most couples. Some pairs end up paying significantly more in combined federal income tax after getting married than they would as two single filers. This is the marriage penalty. Others end up paying less than they would separately. This is the marriage bonus. Whether you face a penalty or bonus depends almost entirely on how similar or different your incomes are.
Here is exactly how it works in 2026, with numbers.
How the Marriage Penalty Works
The marriage penalty occurs when two people with similar incomes marry and find that their combined income pushes them into a higher joint tax bracket than they would have reached individually.
Consider two filers who each earn $100,000 in 2026. Filing as single, each would use the single filer brackets. The 22% rate applies to single income between $48,475 and $103,350. Both filers fall mostly in the 22% bracket individually.
As married filing jointly (MFJ), their combined $200,000 in income hits the 24% bracket (which starts at $206,700 for MFJ in 2026). Wait -- in this case they actually avoid the 24% bracket entirely. But extend this example: if each earns $130,000 ($260,000 combined), as single filers each would be in the 24% bracket (which starts at $103,350 for single). As MFJ, $260,000 puts them in the 24% bracket as well -- but the MFJ bracket starts at $206,700, not $206,700 x2. The brackets are not perfectly doubled for all income levels, which is where the penalty or bonus appears.
Where the Penalty Is Most Severe: The 32% Bracket
The 2026 tax brackets show the penalty most clearly at higher incomes. The 32% bracket begins at $197,300 for single filers and $394,600 for MFJ. This is exactly doubled -- no penalty at this threshold. But the 35% bracket begins at $250,525 for single and $501,050 for MFJ. Again, exactly doubled.
For most income ranges in 2026, Congress has structured the MFJ brackets as exactly twice the single brackets, largely eliminating the marriage penalty at ordinary income levels. However, the penalty still surfaces in two places:
1. Capital gains and NIIT thresholds. The 0% long-term capital gains rate applies to single filers with taxable income up to $48,350 and MFJ filers up to $96,700. That is exactly doubled. But the 3.8% Net Investment Income Tax kicks in at $200,000 for single and only $250,000 for MFJ -- not doubled. A couple each earning $175,000 ($350,000 combined) would both owe NIIT as MFJ but would each avoid it as single filers.
2. The Alternative Minimum Tax (AMT). The AMT exemption for single filers in 2026 is approximately $88,100 and for MFJ is approximately $137,000 -- not doubled. High-income couples with significant AMT preference items may face a larger AMT exposure as MFJ than as two single filers.
The Marriage Bonus: When Marriage Reduces Taxes
The marriage bonus occurs when one spouse earns significantly more than the other -- or when one spouse earns nothing. In this case, the higher-earning spouse effectively gets to share the lower-income spouse's bracket space.
Example: One spouse earns $180,000, the other earns $30,000. As single filers in 2026, the higher earner would owe approximately $34,200 in federal income tax, and the lower earner approximately $3,100, for a combined $37,300.
As MFJ, their combined $210,000 is taxed using joint brackets. The standard deduction is $30,000 (MFJ 2026), making taxable income $180,000. Their estimated tax comes out to approximately $30,000 to $32,000 -- several thousand less than filing separately. That difference is the marriage bonus.
The bonus is largest when one spouse earns all or most of the household income and the other earns little or nothing. The high earner gets to fill up the wide lower brackets shared with a $0-earning spouse.
Standard Deduction Comparison
The 2026 standard deduction is $15,750 for single filers and $31,500 for married filing jointly. This is exactly doubled, so there is no advantage or disadvantage on the standard deduction alone. A couple with no itemized deductions gets the same benefit whether measured as two singles or as one joint filer.
Married Filing Separately: Usually Not the Answer
Some couples assume they can avoid the marriage penalty by filing as married filing separately (MFS). In practice, MFS is almost always worse. The MFS standard deduction is $15,750 (same as single), but MFS filers lose eligibility for the Earned Income Credit, most education credits, the child and dependent care credit (in most cases), and deduction for student loan interest. MFS also disqualifies higher earners from Roth IRA contributions entirely at lower income thresholds.
The only common scenarios where MFS makes sense: one spouse has very large medical expenses (limited by 7.5% of AGI, so lower AGI helps) or specific income-driven student loan repayment situations where keeping incomes separate on the return is required.
How to Calculate Your Marriage Penalty or Bonus
The calculation is straightforward:
- Calculate each spouse's federal tax as if filing single with their own income and the single standard deduction.
- Add the two amounts together.
- Calculate the couple's joint federal tax using MFJ brackets and the $31,500 MFJ standard deduction.
- Subtract the joint tax from the combined single tax. Positive result = marriage bonus. Negative result = marriage penalty.
Use the Income Tax Calculator to run both scenarios. Enter each spouse's income as a single filer, record both tax estimates, then enter the combined income as married filing jointly to see the joint tax. The difference is your penalty or bonus.
Planning Opportunities
If you face a marriage penalty, there are a few planning tools. Maximizing pre-tax retirement contributions (401k, traditional IRA) reduces both spouses' AGI and may pull income below key thresholds. Timing the realization of capital gains or Roth conversions to years when combined income is lower can also help. If both spouses have flexibility in their W-4 withholding, recalculating withholding right after marriage prevents underpayment surprises at filing time.