The wedding changes your taxes from the year you marry, even if the ceremony is on December 30. This guide covers the federal rules from IRS sources: which filing status you can use, what to change at work, why the name on your return matters, and how the 2026 tax brackets decide whether marriage lowers or raises your bill.
This is general information, not tax advice. If you own a business, have big differences in income, student loans on income-driven repayment, or live in a community property state, run your numbers with a tax professional.
1. Your status on December 31 decides the whole year
The IRS sets your marital status on the last day of the tax year, December 31 for most people. If you are married that day, you are considered married for the whole year (IRS Publication 501). A December wedding means you file as a married couple for that year. A wedding on January 2 means you both file as single (or head of household, if you qualify) for the year before.
Once married, you have two options:
| Married filing jointly (MFJ) | Married filing separately (MFS) | |
|---|---|---|
| Returns | one return, combined income | two returns |
| 2026 standard deduction | $32,200 | $16,100 each |
| Liability | both of you are responsible, jointly and individually, for the tax | each for your own return |
| Credits | full access | several limited or lost (below) |
| Switching later | can't switch to separate after the due date | can switch to joint with Form 1040-X within 3 years of the separate return's due date |
IRS Tax Tip 2026-54 says joint filing is usually more beneficial, but recommends calculating your tax both ways.
What you give up when filing separately
According to Publication 501, if you file separately:
- your tax rate is generally higher than on a joint return;
- you generally can't take the child and dependent care credit, the adoption credit, the education credits or the student loan interest deduction;
- you can't take the earned income credit unless you have a qualifying child and meet other requirements;
- your capital loss deduction is limited to $1,500 instead of $3,000;
- if your spouse itemizes, you can't take the standard deduction;
- several credits, including the child tax credit, phase out at half the joint-return income levels.
Why would anyone file separately? Usually for reasons outside the tax table. One example is keeping liability separate: on a joint return, "if one spouse doesn't pay the tax due, the other may have to" (Publication 501). Other reasons are a payment plan tied to income, or one spouse with large deductions that depend on income. This is where a professional is worth paying for.
2. Name change: Social Security first, then the IRS
If either of you changes your name, report it to the Social Security Administration before you file. The name on your return must match SSA records, otherwise processing can be delayed (IRS Tax Tip 2026-54). The step-by-step process is in our guide how to change your name after marriage.
If you moved, the IRS address form is Form 8822 (change of address). It is not used for name changes.
3. Update your W-4, especially if you both work
The IRS tip says newlyweds should give their employers a new Form W-4 within 10 days. The 2026 Form W-4 handles a working spouse in Step 2 (Multiple Jobs or Spouse Works). Pick one option:
- (a) use the IRS Tax Withholding Estimator (the most accurate, and the right choice if either of you is self-employed);
- (b) fill in the Multiple Jobs Worksheet and enter the result in Step 4(c);
- (c) if there are only two jobs in total, check the box on both W-4s. The form says this is generally more accurate than (b) when the lower-paid job pays more than half of the higher-paid one.
Complete Steps 3–4(b) on only one of the forms, ideally for the highest-paying job.
Why it matters: each employer withholds as if its paycheck were your only household income. Two salaries on "married" withholding without Step 2 can leave you under-withheld and owing tax in April.
The Additional Medicare Tax trap
The 0.9% Additional Medicare Tax applies above $250,000 for married filing jointly, $125,000 for married filing separately and $200,000 for everyone else (IRS Topic 560). Employers start withholding it only when your own wages pass $200,000. Two spouses earning $150,000 each won't have it withheld, but together they owe it on $50,000. Plan for that with the W-4 or estimated payments.
4. Marriage bonus or marriage penalty? The 2026 brackets
For 2026, the IRS brackets (Rev. Proc. 2025-32) look like this:
| Rate | Single: taxable income over | Married filing jointly: over | Joint = 2 × single? |
|---|---|---|---|
| 10% | $0 | $0 | yes |
| 12% | $12,400 | $24,800 | yes |
| 22% | $50,400 | $100,800 | yes |
| 24% | $105,700 | $211,400 | yes |
| 32% | $201,775 | $403,550 | yes |
| 35% | $256,225 | $512,450 | yes |
| 37% | $640,600 | $768,700 | no (2 × $640,600 = $1,281,200) |
The married filing separately table matches single up to the 35% bracket, then hits 37% at $384,350, half the joint threshold.
Because the joint brackets and the standard deduction ($32,200 vs 2 × $16,100) are exactly double the single figures up to the 35% bracket, the result depends on how your incomes are split:
- One earner, or very unequal incomes → marriage bonus. The higher earner's income is spread over wider joint brackets.
- Similar incomes below the top bracket → roughly no change.
- Two high earners in the 37% bracket → marriage penalty, because the joint 37% threshold is far less than twice the single one.
Worked examples (2026 federal income tax only)
Here "income" means income before the standard deduction. These examples use only the brackets and standard deduction. They ignore credits, other deductions, payroll taxes and state tax.
| Couple | Two single returns | Joint return | Difference |
|---|---|---|---|
| $136,100 + $0 | $21,398 | $12,282 | $9,116 less (bonus) |
| $300,000 + $60,000 | $73,154 | $63,868 | $9,286 less (bonus) |
| $96,100 + $96,100 | $24,624 | $24,624 | $0 |
| $716,100 + $716,100 | $429,915 | $440,165 | $10,250 more (penalty) |
How the first row works: as a single filer, $136,100 − $16,100 = $120,000 taxable, so the tax is $17,966 + 24% × ($120,000 − $105,700) = $21,398. Jointly, $136,100 − $32,200 = $103,900 taxable, so the tax is $11,600 + 22% × ($103,900 − $100,800) = $12,282.
Penalties hiding outside the brackets
Even when the brackets are neutral, other rules may not double for married couples:
- the Additional Medicare Tax threshold: $250,000 jointly vs $200,000 per single person (see above);
- the earned income credit and other income-tested credits, which can shrink or disappear when two incomes are combined;
- items listed in Rev. Proc. 2025-32 with their own joint thresholds. Check each one that applies to you.
5. State taxes: check separately
State rules differ. Some states start from your federal filing status, others have their own options or brackets that are not doubled for couples. In the nine community property states (Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, Washington, Wisconsin), spouses who file separate federal returns generally must each report half of the community income (IRS Publication 555). Check your state revenue department's site before deciding how to file.
Newlywed tax checklist
- Name change? Update Social Security first, then your employer's payroll.
- New address? File Form 8822 with the IRS and update the post office and employers.
- Submit a new 2026 W-4 for each job. Use Step 2 if you both work.
- Check the Additional Medicare Tax if your combined wages may top $250,000.
- Keep W-2s, 1099s and both of your last returns together for the first joint filing.
- At filing time, compare joint vs separate.
Starting your shared finances? Our monthly savings calculator helps with the next goal. If you signed one, our prenup basics explains what it does and doesn't cover. A prenup doesn't change your filing options.
FAQ
We married in December. Do we have to file jointly for that year?
You are considered married for the whole year, so your options are married filing jointly or separately, not single.
Can we file jointly if only one of us has income?
Yes. That is the classic case where joint filing usually saves money.
We filed separately. Can we change our minds?
Yes. You can amend to a joint return with Form 1040-X, generally within 3 years of the due date of the separate returns. Going from joint to separate after the due date is not allowed (Publication 501).
Does a different last name on our return cause problems?
Only if it doesn't match Social Security records. Update SSA first, and use the name SSA has when you file.
Sources
- IRS Rev. Proc. 2025-32 (2026 tax rate tables, section 4.01; standard deduction, section 4.14): https://www.irs.gov/pub/irs-drop/rp-25-32.pdf
- IRS Tax Tip 2026-54, Marriage means making changes before next filing season (7 July 2026: SSA before filing; Form 8822; new W-4 within 10 days; December 31 rule; compare both ways): https://www.irs.gov/newsroom/marriage-means-making-changes-before-next-filing-season
- IRS Publication 501 (2025), Dependents, Standard Deduction, and Filing Information (marital status on the last day of the year; MFS limits; joint responsibility; changing status): https://www.irs.gov/publications/p501
- IRS Form W-4 (2026), Step 2 options and instructions: https://www.irs.gov/pub/irs-pdf/fw4.pdf
- IRS, About Form W-4: https://www.irs.gov/forms-pubs/about-form-w-4
- IRS Topic No. 560, Additional Medicare Tax (thresholds $250,000 / $125,000 / $200,000; employer withholding over $200,000): https://www.irs.gov/taxtopics/tc560
- IRS Publication 555 (12/2024), Community Property (nine states; half of community income on separate returns): https://www.irs.gov/publications/p555
- Figures as of 27 October 2026. This article is general information, not tax or legal advice.