Married Filing Separately

Each spouse files a Form 1040 with the married filing separately box checked and lists the other spouse’s name and Social Security number. You report your own wages, your own investment income and your own deductions. In the nine community property states, state law may make half of some income each spouse’s, and each separate return attaches Form 8958 to show how income and deductions were divided.

The rate schedule for 2026 is exactly half the joint one at every rate: the 12% bracket ends at $50,400 of taxable income and the 37% rate starts at $384,350. The standard deduction is $16,100, but the two returns are linked. If one spouse itemizes, the other can’t take the standard deduction at all and must itemize too, even with almost nothing to deduct.

You must file this way if your spouse won’t agree to a joint return, unless you qualify as head of household. That status is open to a married parent whose spouse didn’t live in the home during the last six months of the year, and it gives a larger deduction, wider brackets and freedom from the itemizing rule.

The IRS says plainly that you usually pay more tax on a separate return. Because the separate brackets are exactly half the joint ones, a couple with equal incomes loses little on rates alone. Uneven incomes are another matter: the higher earner can’t use the lower earner’s unused brackets, which costs the $120,000 and $40,000 couple in the example below $2,650 a year. Then comes a long list of benefits that disappear or shrink:

Some of the harshest rules apply only if you lived with your spouse at any time during the year, even for a day. Spouses who lived apart all year are generally treated like single filers for these tests.

Social Security is the biggest. For a joint return, benefits start to become taxable above $32,000 of provisional income; on a separate return by a spouse who lived with the other, the base amount is $0, so benefits become taxable from the first dollar, up to 85% of them.

Retirement savings are squeezed too. Direct Roth IRA contributions phase out between $0 and $10,000 of modified AGI, and so does the traditional IRA deduction for a spouse covered by a workplace plan. The $25,000 allowance for rental real estate losses disappears; spouses who lived apart all year get $12,500 each.

Medicare surcharges use a separate three-tier table, set from the return filed two years earlier. For 2026, IRMAA is $0 up to $109,000 of modified AGI, then jumps straight to a $446.30 monthly Part B surcharge (a $649.20 total premium) plus $83.30 for Part D, rising to $487.00 and $91.00 at $391,000. A couple with $220,000 of joint MAGI pays the first tier, $81.20 a month each for Part B; split evenly across two separate returns, the same income puts each spouse in the $446.30 tier.

Despite the costs, separate returns win in a handful of situations. The most common is federal student loans: on the income-driven repayment plans, a married borrower who files separately has only their own income used to set the payment. When the lower payment saves more than the extra tax, the separate return comes out ahead.

Deductions limited by a share of income are another case. Medical expenses, for instance, count only above a percentage of adjusted gross income, so a spouse with large bills and a modest income may deduct more against a separate AGI than against the couple’s combined one.

Then there is liability. On a separate return you are responsible only for your own tax, which matters if you doubt that your spouse is reporting all their income or paying what they owe. Separated spouses who aren’t yet divorced and can’t agree on a joint return have to file this way unless one of them qualifies as head of household.

State tax can swing the answer either way, so the IRS suggests comparing the combined federal and state bill both ways before choosing.

Filing status is chosen fresh each year, so a couple can file separately one year and jointly the next. Within a year, the rules are lopsided. If you filed separate returns, you can switch to a joint return by filing Form 1040-X, generally within three years of the original due date, not counting extensions. So a separate return can still be revisited later, while a joint return becomes final.

The reverse doesn’t work. Once a joint return is filed, you can’t change to separate returns for that year after the due date. The only exception lets the personal representative of a deceased spouse replace a joint return filed by the survivor with a separate one within a year of the due date, including extensions.