How Does Marriage Change Your Taxes?

The Marriage Tax: Bonus or Penalty?

Getting married changes your tax filing status from single to married filing jointly (or married filing separately), which affects your tax brackets, standard deduction, and eligibility for numerous credits and deductions. Whether this change produces a marriage bonus (paying less tax together than separately) or a marriage penalty (paying more together than separately) depends almost entirely on how similar your incomes are.

The marriage bonus is most pronounced when one spouse earns significantly more than the other — ideally when one earns most or all of household income. In this case, combining incomes on a joint return shifts some of the higher earner's income into lower brackets, producing meaningful tax savings. A couple where one earns $120,000 and one earns $0 may save $5,000-$8,000 annually versus the single filer status.

The marriage penalty applies when both spouses earn similar incomes, particularly at higher income levels. Two single filers each earning $200,000 each pay less total tax than a married couple with $400,000 combined income, because the married brackets stack faster at high income levels. The TCJA of 2017 reduced but did not eliminate the marriage penalty — it still exists at higher income levels and for some credits and phase-outs.

Calculate your marriage tax change

Enter both spouses' incomes to see your combined MFJ tax versus your previous single filer totals — and the exact annual marriage bonus or penalty.

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How Marriage Affects Every Major Tax Category

1
Tax brackets: MFJ brackets are wider than single for most income levels
For 2024, the MFJ brackets are roughly double the single brackets through the 32% range — meaning two equal earners filing jointly face the same marginal rates as they would as single filers. Above the 32% bracket, MFJ brackets narrow relative to double the single brackets, creating the higher-income penalty. For unequal incomes, MFJ almost always produces lower tax because the joint brackets accommodate the combined income more efficiently.
2
Standard deduction: exactly doubled for MFJ
The 2024 standard deduction is $14,600 single versus $29,200 MFJ — precisely double. This means marriage does not create a deduction advantage or disadvantage relative to combining two single filer deductions. No penalty or bonus here.
3
Credits and phase-outs: often penalize dual high-income couples
Many tax credits phase out based on AGI. Child tax credit, education credits, IRA deductibility, and EITC all have income thresholds. Two high earners who were each below a phase-out threshold as singles may find their combined MFJ income exceeds the (not-doubled) married threshold, reducing or eliminating credits. This phase-out compression is a significant source of marriage penalty for dual high-income households.
4
FICA taxes: completely unaffected by marital status
Social Security (6.2%) and Medicare (1.45%) are payroll taxes calculated on individual wages — your marital status and filing status have no effect on FICA. The Additional Medicare Tax (0.9% on wages above $200,000 single / $250,000 MFJ) is the one exception — the MFJ threshold is not double the single threshold, creating a modest penalty for dual earners.
5
Capital gains: marriage rarely changes the rate
Long-term capital gains rate thresholds for MFJ are exactly double those for single filers (0% rate applies up to $94,050 MFJ versus $47,025 single in 2024). This means marriage neither penalizes nor benefits most couples on capital gains. At very high income levels, the 20% rate threshold is not doubled, creating a modest penalty for high-income couples with significant investment income.

Marriage Bonus vs Marriage Penalty: When Each Applies

Marriage Bonus (Lower Tax Together)

✓One spouse earns significantly more than the other
✓One spouse stays home or works part-time
✓Large income disparity shifts higher earner into lower brackets
✓Most pronounced when income ratio is 3:1 or more
✓Can save $3,000-$10,000+ per year depending on incomes
✓Most common scenario for marriages with primary/secondary earner structure

Marriage Penalty (Higher Tax Together)

✗Both spouses earn similar, high incomes
✗Combined income exceeds phase-out thresholds that each avoided as singles
✗Most pronounced when both spouses earn $150,000-$400,000
✗Can cost $2,000-$15,000+ per year depending on incomes
✗Exacerbated by SALT cap, credit phase-outs, and AMT at high incomes
✗Most common in dual high-earning professional households

Frequently Asked Questions

Should we file jointly or separately?

Married filing separately (MFS) is almost always more expensive than married filing jointly (MFJ). MFS eliminates the student loan interest deduction, reduces or eliminates the child tax credit and dependent care credit, and requires both spouses to either itemize or take the standard deduction — you cannot mix. The only scenarios where MFS sometimes makes sense: one spouse has significant medical expenses exceeding the 7.5% AGI floor (which is lower on a single income), or for income-driven student loan repayment where one spouse's income should not be combined.

Does marriage affect my student loan repayment?

Yes, significantly for income-driven repayment (IDR) plans. Under most IDR plans, payments are based on combined household income for MFJ filers. If your spouse has significantly higher income, this can dramatically increase your required monthly payment. Filing separately preserves lower payments based on your income alone — but costs more in taxes. Calculate the tax cost of filing separately versus the student loan payment increase from filing jointly to determine which is less expensive overall.

How does marriage affect IRA contribution deductibility?

If your spouse is covered by a workplace retirement plan (401k, 403b, pension) and you are not, your ability to deduct Traditional IRA contributions phases out at a higher MFJ income level ($230,000-$240,000 in 2024) than the single covered-by-plan threshold ($77,000-$87,000). If you are covered by a workplace plan, the MFJ deductibility phase-out is $123,000-$143,000. Marriage can either help or hurt deductibility depending on your specific situation.

What happens to our taxes when we have children?

Children provide significant tax benefits: the Child Tax Credit ($2,000 per qualifying child under 17, partially refundable), the Child and Dependent Care Credit (up to $1,050 for one child, $2,100 for two+ in childcare), and the ability to contribute to a Dependent Care FSA ($5,000 pre-tax per household). These benefits phase out at higher incomes. Children also create the Head of Household filing status for single parents — a more favorable bracket than single.

Is there a tax advantage to getting married before or after December 31?

Yes. Your filing status on December 31 determines your status for the entire tax year. If getting married on December 31 (versus January 1) produces a tax bonus in the marriage year, it may be worth timing. If it produces a penalty, delaying until January 1 preserves single filer status for one more year. The calculator can model both scenarios for the specific tax year in question.

Does marriage affect Social Security benefits?

Yes, in several ways. Spousal Social Security benefits allow a spouse with low or no earnings history to claim up to 50% of their spouse's full retirement benefit. Survivor benefits allow a widow or widower to claim 100% of the deceased spouse's benefit. The higher-earning spouse delaying Social Security to age 70 maximizes both their own benefit and the survivor benefit — a particularly important strategy for married couples with income disparity.

Calculate your exact marriage tax change

See the dollar difference between your combined MFJ tax and what you paid as two single filers — and whether you face a bonus or a penalty.

Calculate My Marriage Tax