How Getting Married Affects Your Taxes: Filing Jointly vs. Separately
Marriage changes your tax situation immediately. You can no longer file as "Single" — you must choose between Married Filing Jointly (MFJ) or Married Filing Separately (MFS). For most couples, filing jointly saves money. But there are important exceptions. Here's how to think through the decision.
Updated April 2026 · 13 min read
Your Filing Options After Marriage
If you are legally married on December 31 of the tax year — even if you got married on December 31 — the IRS considers you married for the entire year. Your options are:
Married Filing Jointly (MFJ)
One combined return. Both spouses' incomes, deductions, and credits combined. Both are jointly responsible for the tax owed.
Married Filing Separately (MFS)
Separate returns. Each spouse only reports their own income and deductions. Often results in higher combined tax, plus losing many credits.
Head of Household
Only available if you lived apart from your spouse for the last 6 months of the year AND maintained a home for a dependent. Rare.
Marriage Bonus vs. Marriage Penalty
Whether marriage helps or hurts your taxes depends on whether your combined income is taxed more or less favorably than it would be if you were both single. The US tax code was designed with the assumption of a single-earner household — so the results are uneven.
Marriage Bonus
When married couples pay less combined tax than they would as two single filers. Occurs when:
- • One spouse earns significantly more than the other
- • One spouse earns little or nothing
- • The higher earner benefits from being in lower MFJ brackets
Marriage Penalty
When married couples pay more combined tax than they would as two single filers. Occurs when:
- • Both spouses have high, similar incomes
- • Both are in the 32%+ bracket individually
- • The MFJ bracket thresholds are less than 2× the single thresholds
MFJ tax (combined)
$16,033
MFS tax (combined)
$16,034
Verdict
roughly neutral
When two spouses earn identical salaries, their combined tax under MFJ is essentially the same as filing separately. This is the true marriage-neutral scenario.
MFJ tax (combined)
$18,303
MFS tax (combined)
$22,400
Verdict
marriage bonus
The higher earner's income is partially taxed at lower rates because it's combined with the lower earner's income under the wider MFJ brackets. Filing jointly saves roughly $4,000 vs. separately.
MFJ tax (combined)
$88,276
MFS tax (combined)
$83,100
Verdict
marriage penalty
Two high earners hit the top brackets faster when combined. The 32% and 35% bracket thresholds for MFJ are not double the single thresholds, creating a penalty. Couples in this scenario pay more than if they could file as single.
How Brackets Shift When You Marry
For most brackets, the MFJ threshold is exactly double the single threshold — meaning no penalty or bonus. The "marriage penalty zone" lives in the 32%, 35%, and 37% brackets, where the MFJ threshold is less than double the single threshold:
| Rate | Single threshold | MFJ threshold | MFJ = 2× Single? |
|---|---|---|---|
| 10% | $12,200 | $24,500 | Yes ✓ |
| 12% | $49,750 | $99,550 | Yes ✓ |
| 22% | $106,100 | $212,100 | Yes ✓ |
| 24% | $202,500 | $404,900 | Yes ✓ |
| 32% | $257,050 | $514,100 | No — penalty zone |
| 35% | $642,700 | $771,200 | No — penalty zone |
| 37% | Over $642,700 | Over $771,200 | No — penalty zone |
When Filing Separately (MFS) Actually Makes Sense
MFS is almost always the worse choice for taxes alone — but other financial factors can make it worth the extra tax cost:
Income-driven student loan repayment (IDR)
If one spouse has significant federal student loan debt on an income-driven repayment plan (IBR, PAYE, SAVE), your payment is calculated based on household income if you file jointly. Filing separately keeps your payment lower — though you sacrifice valuable tax benefits. Run the math: the student loan savings sometimes exceed the tax cost of filing separately.
Protecting yourself from a spouse's tax liability
When you file jointly, you're jointly and severally liable for the entire tax bill — including any errors or fraud your spouse committed. If you have reason to doubt your spouse's tax compliance, filing separately insulates you. You can also request 'innocent spouse relief' in some cases, but filing separately is cleaner prevention.
Medical expense deductions
Medical expenses are only deductible to the extent they exceed 7.5% of AGI. If one spouse has high medical expenses and a relatively low individual income, filing separately gives them a lower AGI threshold to clear — potentially making more of those expenses deductible.
Separation or divorce proceedings
If you're separated but not legally divorced by December 31, you're still considered married for tax purposes. Some couples in contentious separations file separately simply to avoid the need to cooperate on a joint return. Note: if either spouse itemizes on a separate return, the other must itemize too.
Impact on Tax Credits and Deductions
This is the biggest reason MFS usually loses: it disqualifies you from many valuable credits entirely.
| Tax Benefit | Winner |
|---|---|
| Earned Income Tax Credit (EITC) | MFJ wins |
| Child Tax Credit | MFJ wins slightly |
| Child and Dependent Care Credit | MFJ wins |
| American Opportunity / Lifetime Learning Credit | MFJ usually wins |
| Student Loan Interest Deduction | MFJ wins |
| Roth IRA Contribution Eligibility | MFJ wins significantly |
| IRA Deduction (if covered by workplace plan) | MFJ wins |
| Premium Tax Credit (ACA) | MFJ wins |
MFS disqualifies or severely limits the majority of commonly used tax credits — often making any tax saving from separate filing worthless.
What to Do in the Year You Get Married
Update your W-4 at work
After marriage, update your Form W-4 with your employer. Your withholding should reflect your combined household income and new filing status. Use the IRS Tax Withholding Estimator at irs.gov to get the right numbers — under-withholding can mean an April surprise.
Run both scenarios before filing
Most tax software (TurboTax, H&R Block, FreeTaxUSA) will calculate both MFJ and MFS automatically and show you the difference. Always run both before choosing.
Check your health insurance and FSA situations
Combining onto one spouse's employer plan may change your costs. Dependent Care FSA limits are per household ($5,000/year total, not per person). Review both employers' benefits.
Review beneficiary designations
Marriage automatically changes your legal next-of-kin but does NOT automatically update 401(k) or IRA beneficiary designations. Update them explicitly at your financial institutions.
Related Tools
- Tax Bracket Estimator → Estimate your bracket under both MFJ and MFS scenarios.