Getting married is a major tax event. Your filing status changes, your standard deduction doubles (or nearly so), your tax bracket thresholds shift, and your eligibility for various credits and deductions may change. Whether marriage makes your combined tax bill go up or down depends primarily on how similar your two incomes are.
Filing Status Options After Marriage
Once married, you can file as Married Filing Jointly (MFJ) or Married Filing Separately (MFS). Almost all married couples benefit from filing jointly. MFS has higher effective tax rates on the same income, eliminates eligibility for several credits (Earned Income Credit, American Opportunity Credit, student loan interest deduction), and limits IRA deductibility. The rare cases where MFS makes sense: one spouse has significant medical expenses or miscellaneous deductions that are easier to hit thresholds on with a lower individual AGI, or there are concerns about joint liability for a spouse's tax issues.
The Marriage Bonus
A marriage bonus occurs when combining incomes and filing jointly results in a lower total tax than the two would have paid as singles. This happens most often when one spouse earns significantly more than the other -- the lower-earning spouse's income fills up lower brackets that were already exhausted by the higher earner.
Example: One spouse earns $120,000, the other earns $30,000. As singles: the higher earner pays approximately $21,000 in federal tax; the lower earner pays approximately $1,400. Total: $22,400. As MFJ: on $150,000 combined income, tax is approximately $19,800. Marriage bonus: $2,600.
The Marriage Penalty
A marriage penalty occurs when two high earners combine incomes and find their joint brackets are not exactly double the single brackets -- particularly at higher income levels where the brackets narrow. The 32%, 35%, and 37% brackets start sooner (relative to combined income) for married couples than for two singles.
Example: Both spouses earn $180,000. As singles: each pays approximately $35,000, total $70,000. As MFJ on $360,000: approximately $74,000. Marriage penalty: $4,000. This is most acute when both spouses have high, similar incomes.
What to Do After Getting Married
- Update your W-4: Both spouses should update their Form W-4 with their employer within weeks of marriage. The new W-4 has a specific section for dual-income couples. Failure to update can result in underwithholding and an unexpected tax bill.
- Review beneficiary designations: Retirement accounts, life insurance, and other accounts pass outside of a will. Update beneficiaries.
- Consider name changes: If either spouse changes their name, it must match Social Security Administration records exactly when you file your return.
- Reassess retirement contributions: A spouse who was phased out of Roth IRA contributions as a single may be eligible again (or vice versa) under joint income thresholds.
Use our Income Tax Calculator to compare your tax as single filers versus married filing jointly to see your marriage bonus or penalty.
Tax Implications of Marriage — Planning Checklist
Getting married changes your tax situation in ways that go far beyond simply combining incomes and filing jointly. Some changes are immediately beneficial; others create unexpected obligations. Here's what to plan for in the year you marry and beyond.
The Marriage Bonus vs. Marriage Penalty
The marriage bonus occurs when combining two incomes results in a lower total tax bill — typically when one spouse earns significantly more than the other. The marriage penalty is the opposite: two similar high incomes combined can push the couple into higher brackets faster than the same income would for two single filers. For most couples where one spouse earns significantly more, marriage is a net tax benefit. For dual-income couples where both earn similar high salaries, the penalty can be real near the top brackets.
Update Your W-4 Immediately
Once married, both spouses should submit updated W-4 forms to their employers. The IRS withholding tables changed significantly in 2020, and failing to update your W-4 after marriage frequently results in under-withholding — leading to a tax bill and possible underpayment penalty. Complete Step 2 of the W-4 (Multiple Jobs Worksheet) or use the IRS Tax Withholding Estimator to get the right amount.
Income Thresholds That Work Against Dual-Income Couples
- Additional Medicare Tax (0.9%): Applies above $200,000 for single filers but only $250,000 for married filing jointly — meaning dual-income couples hit this surcharge at a lower combined income than if both remained single.
- Net Investment Income Tax (3.8%): Same dynamic — $200,000 single vs. $250,000 married.
- Roth IRA income limits: Phase out at $236,000 for married couples (2025), which may be lower than the combined single thresholds for high-earning couples.
Standard Deduction Doubles — But So Does the Bar for Itemizing
The married filing jointly standard deduction is exactly double the single deduction — $31,500 in 2026 vs. $15,750. However, if one spouse was previously itemizing as a single filer (common for homeowners), the couple now needs to clear the $31,500 threshold to benefit from itemizing. Whether this works in your favor depends on your combined deductible expenses.
Use our income tax calculator to model your combined income under married filing jointly, and our 2026 tax bracket guide for the MFJ bracket thresholds.
The Year You Get Married: Partial-Year Considerations
For federal income tax purposes, your filing status on December 31 of the tax year determines your filing status for the entire year. If you get married on December 31, you are considered married for the full tax year -- you can file jointly or separately for that year. If you get married on January 1 of the following year, you are single for the full prior year. There is no prorating of brackets, deductions, or credits based on the date of marriage within the year. This creates a natural planning opportunity: couples who will benefit from filing jointly (due to the marriage bonus) may want to time their marriage to capture that benefit for a full year, while the specific timing matters less for couples who face a marriage penalty.
Joint and Several Liability: What Married Filing Jointly Means Legally
When you file a joint return, both spouses sign the return and are jointly and severally liable for the full tax owed. This means the IRS can collect the entire tax liability from either spouse -- not just their proportional share. If one spouse has unreported income or erroneous deductions, the other spouse can be held responsible for the resulting tax, interest, and penalties. This is why some spouses with concerns about a partner's financial history choose to file separately despite the higher tax cost -- it limits their exposure to the other spouse's tax issues. The "innocent spouse" provisions (Form 8857) provide some relief in egregious cases, but they require meeting strict IRS criteria and can take years to resolve. For the vast majority of married couples with straightforward financial lives, joint filing is clearly the right choice -- but the legal implications of joint liability are worth understanding.
FICA Implications of Marriage
FICA taxes (Social Security and Medicare) are calculated per employee, not per household. Your marital status has no effect on FICA. Each spouse continues to pay 6.2% Social Security tax on wages up to the Social Security wage base ($184,500 in 2026) and 1.45% Medicare tax on all wages. However, the Additional Medicare Tax of 0.9% applies above $200,000 for single filers but only $250,000 for married filing jointly -- not double the single threshold. This means a couple where each spouse earns $180,000 ($360,000 combined) would not owe the Additional Medicare Tax as singles (each under $200,000), but may owe it as married filers if their employer withholds at the incorrect rate. Employers withhold the Additional Medicare Tax on individual wages above $200,000 without regard to filing status -- so married couples may find they overpaid or underpaid this tax depending on each spouse's individual earnings. Form 8959 reconciles any discrepancy at filing.