How Filing as Married Affects Taxes: Brackets, Credits, Penalties

Getting married changes your federal taxes the day the marriage is legal, and the change applies to the entire tax year. How filing as married affects your taxes comes down to three things: your filing status is set by your status on December 31, your income and your spouse’s are combined into one set of brackets with a doubled standard deduction, and the income thresholds for most credits shift to a couple’s combined figure. For most households that lowers the total bill. For two high earners, or two low earners with kids who both qualified for the Earned Income Tax Credit, it can raise it.

When the IRS Considers You Married for the Year

Federal law fixes your marital status on the last day of the tax year.¹ Marry any time during the year, even on December 31, and you file as a married taxpayer for that whole year. Divorce finalized by December 31 works the same way in reverse: you file as unmarried for the full year. A legal separation under a court decree of divorce or separate maintenance also counts as unmarried. Living apart without a court order does not.

If a spouse dies during the year, the surviving spouse is still considered married for that year and can file a joint return for it.

Joint Return or Separate Returns

Most married couples choose between Married Filing Jointly and Married Filing Separately.² A joint return combines both spouses’ income, deductions, and credits into one filing. It usually produces the lower total tax because it opens the widest brackets, the largest standard deduction, and full access to every credit. The trade-off is joint and several liability: both spouses are on the hook for the entire tax owed on that return, regardless of who earned the income or made the errors. The IRS can collect the full amount from either spouse.

Filing separately keeps each spouse responsible only for their own return. Couples sometimes choose it when one spouse has large medical expenses (deductible only above a percentage of income), when one spouse has concerns about the other’s financial dealings, or when income-driven student loan payments would jump with a combined income. The cost is high, because separate filing restricts almost every major credit and deduction.

A narrow third path exists for some married people living apart. If you file your own return, paid more than half the cost of keeping up your home for the year, your spouse did not live in the home during the last six months of the year, and your home was the main home of your child, stepchild, or foster child for more than half the year and you can claim that child as a dependent, you can file as Head of Household.³ That gives you better brackets and a higher standard deduction than MFS or single without a finalized divorce.

The Standard Deduction After Marriage

The standard deduction is a flat amount subtracted from your income before rates apply. For 2026:⁴

Married Filing Jointly: $32,200
Single or Married Filing Separately: $16,100
Head of Household: $24,150

The joint amount is exactly twice the single and MFS amounts, so the standard deduction itself carries no marriage penalty or bonus. One rule bites, though: if one spouse itemizes on Schedule A, the other cannot claim the standard deduction.⁵ Both spouses have to use the same method. If one spouse itemizes because of mortgage interest, state taxes, and charitable contributions, the other has to itemize too, even if their own deductions are minimal.

Taxpayers 65 and older get an additional standard deduction. For married filers, that extra amount is $1,650 per qualifying spouse. Recent legislation also allows taxpayers 65 and older to claim an additional $6,000 per person (up to $12,000 for a couple where both qualify), which phases out for joint filers with income above $150,000.⁶

Brackets, the Marriage Bonus, and the Marriage Penalty

Federal income tax is progressive: successive chunks of income are taxed at rising rates. The 2026 brackets for married couples filing jointly:⁴

10%: up to $24,800
12%: $24,801 to $100,800
22%: $100,801 to $211,400
24%: $211,401 to $403,550
32%: $403,551 to $512,450
35%: $512,451 to $768,700
37%: over $768,700

Through the 32% bracket, every joint threshold is exactly double the single-filer threshold. A couple earning $300,000 combined pays the same on those brackets as two single people earning $150,000 each. For most households that eliminates any marriage penalty and often creates a bonus. When one spouse earns significantly more than the other, the wider joint brackets pull income into lower rates than a single filer would face, and the total bill drops.

The penalty shows up higher up the income ladder. The 37% rate starts at $768,700 for joint filers, but a single person does not hit 37% until $640,600. Two single people could each earn up to $640,600 at 35%, a combined $1,281,200, before either crosses into 37%. Married and filing jointly, they cross into 37% below $769,000. When two high earners marry, more of their combined income gets taxed at 35% and 37% than would have been the case as single filers. That is the marriage penalty at the top.

Credits That Move with Your Combined Income

Marriage changes eligibility for most tax credits because the IRS looks at the couple’s combined adjusted gross income, not each spouse’s income separately.

Child Tax Credit

For 2026, the maximum Child Tax Credit is $2,200 per qualifying child. The phase-out starts at $400,000 of combined income for joint filers and $200,000 for everyone else, dropping the credit by $50 for every $1,000 of income above the threshold.⁷ Because the joint threshold is exactly double the individual one, most couples do not lose credit simply by marrying. The pinch is on families where each spouse would have been below $200,000 alone but the couple exceeds $400,000 together.

Earned Income Tax Credit

The EITC can swing hardest against lower-income couples. For 2026, a married couple filing jointly with three or more children can receive up to $8,231, with the credit phasing out completely at $70,224. A couple with one child can receive up to $4,427, phasing out at $58,863.⁴ When two low-income earners marry, combining their incomes can push past these limits and eliminate the credit entirely, a loss that can run into thousands of dollars.

Education Credits and Student Loan Interest

Filing jointly preserves the American Opportunity Credit, the Lifetime Learning Credit, and the deduction of up to $2,500 in student loan interest. Filing separately eliminates all three.³ For couples carrying student debt, this alone often decides the filing question.

Premium Tax Credit

If you buy health coverage through the Marketplace and receive a subsidy, filing separately generally disqualifies you from the Premium Tax Credit.⁸ A narrow exception exists for victims of domestic abuse or spousal abandonment who meet specific criteria. For most married couples, keeping the subsidy means filing jointly.

What You Give Up by Filing Separately

The restrictions run wide.³ Choosing MFS means:

Earned Income Tax Credit: generally unavailable unless you have a qualifying child and meet additional requirements.
Child and Dependent Care Credit: unavailable in most cases; still available if you are legally separated or living apart from your spouse.
Adoption Credit: unavailable in most cases.
Education credits and student loan interest deduction: completely unavailable.
Savings bond interest exclusion: cannot exclude interest from qualified U.S. savings bonds used for higher education.
Credit for the Elderly or Disabled: unavailable if you lived with your spouse at any time during the year.
Child Tax Credit: phase-out begins at half the joint threshold, so the credit starts shrinking at $200,000 instead of $400,000.
Retirement savings credit: phase-out begins at half the joint income level.
Capital loss deduction: limited to $1,500 instead of $3,000.
Dependent care assistance exclusion: capped at $2,500 instead of $5,000.
Social Security benefits: if you lived with your spouse at any time during the year, up to 85% of benefits may be taxable.

Filing separately can still make sense when one spouse has large medical expenses, when separating liability matters more than maximizing credits, or when a student-loan repayment plan penalizes combined income. Run the numbers both ways before committing, because the lost credits often outweigh what separate filing saves.

If You Live in a Community Property State

Filing separately gets more complicated in the nine community property states: Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, Washington, and Wisconsin.⁹ In these states, most income earned during the marriage belongs equally to both spouses regardless of who earned it. If you file separately, each spouse reports half of all community income plus all of their own separate income, and you attach Form 8958 showing how the income was divided. Separate property (assets owned before the marriage or gifts received individually) stays with the spouse who owns it. The line between community and separate property gets technical fast, and getting it wrong invites IRS adjustments.

Update Your Records Before You File

A few administrative steps prevent processing problems on your first married return.

Fix Your Name with Social Security

If you change your last name, report the change to the SSA so its records match the name on your tax return.¹⁰ A mismatch causes the IRS to reject the return. In many states, you can request a corrected card through your online my Social Security account; otherwise, complete Form SS-5 with documentation of the legal name change. Handle this well before filing season.

File a New W-4 with Your Employer

Withholding on each paycheck is based on the Form W-4 on file with your employer. After marriage your filing status, combined income, and available deductions all shift, which means the existing withholding is almost certainly off.¹¹ Submit a new W-4 with your updated filing status. Both spouses should update at the same time so the combined withholding matches the couple’s actual bill. Skip this step and you land on either an unexpected balance due or an oversized refund.

Tell the IRS if You Move

If you move after marrying, update the IRS through Form 8822, a written statement, or your next return.¹² Changes generally take four to six weeks to process. If you previously filed jointly and now have separate addresses, each spouse should notify the IRS individually.

1
Office of the Law Revision Counsel. 26 USC 7703 – Determination of Marital Status
2
Office of the Law Revision Counsel. 26 USC 6013 – Joint Returns of Income Tax by Husband and Wife
3
Internal Revenue Service. Publication 501 (2025), Dependents, Standard Deduction, and Filing Information
4
Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026, Including Amendments from the One, Big, Beautiful Bill
5
Internal Revenue Service. Topic No. 501, Should I Itemize?
6
Internal Revenue Service. 2026 Filing Season Updates and Resources for Seniors
7
Internal Revenue Service. Child Tax Credit
8
Internal Revenue Service. Eligibility for the Premium Tax Credit
9
Internal Revenue Service. Publication 555 (12/2024), Community Property
10
Social Security Administration. How Do I Change or Correct My Name on My Social Security Number Card?
11
Internal Revenue Service. Tax Withholding for Individuals
12
Internal Revenue Service. Address Changes