The Basic Formula for SSDI Taxation

Whether you owe federal income tax on SSDI depends on your combined income, not on SSDI alone. The IRS uses a specific calculation called the "combined income test" to determine what portion of your benefits, if any, is taxable.

Combined income is the sum of three things: your adjusted gross income (AGI) plus nontaxable interest plus half of your SSDI benefits. Once you know your combined income, you compare it to two thresholds. If your combined income exceeds the first threshold, up to 50 percent of your benefits become taxable. If it exceeds the second threshold, up to 85 percent becomes taxable. The thresholds have not changed since 1984 and are $25,000 for single filers and $32,000 for married couples filing jointly.

The calculation itself is not something you do by hand. Form 1040 and the IRS worksheet in Publication 915 walk you through it line by line. But understanding what counts as income and what the thresholds mean will help you know whether you need to file at all.

Key Takeaways

  • Combined income—not SSDI alone—determines whether your benefits are taxable; it includes your AGI, nontaxable interest, and half your SSDI amount.
  • The two federal thresholds are $25,000 for single filers and $32,000 for married filing jointly; they have remained unchanged since 1984.
  • Up to 50 percent of your benefits become taxable if you exceed the first threshold; up to 85 percent if you exceed the second.
  • Work income, pensions, and investment income all count toward combined income, but SSI and some other benefits do not.
  • Publication 915 and the IRS worksheet on Form 1040 provide the exact calculation; many tax software programs do this automatically.

What Counts as Income in the Combined Income Test

The IRS includes several types of income in the combined income calculation. Wages and self-employment income count in full. So do taxable interest and dividends, capital gains, rental income, and pension or annuity payments. If you have a job while receiving SSDI, all of that wage income goes into the calculation.

Nontaxable interest—such as interest from municipal bonds—also counts, even though you do not report it as taxable income on your return. This is a common surprise. If you have a bond portfolio or municipal bond funds, that interest adds to your combined income for the SSDI tax test, even if you never pay tax on it.

Some income does not count. Supplemental Security Income (SSI) is excluded. So are railroad retirement benefits, workers' compensation, and certain veterans' benefits. If you receive both SSDI and SSI, only the SSDI portion is subject to this tax rule.

Half of your SSDI benefit amount itself is added to the calculation. If you receive $1,200 per month in SSDI, that is $14,400 per year, and $7,200 of that goes into the combined income formula.

The Two Tax Thresholds and What They Mean

The first threshold is $25,000 for single filers, head of household filers, and may have access to widows or widowers. For married couples filing jointly, it is $32,000. For married couples filing separately, it is $0—meaning any combined income at all can trigger taxation.

If your combined income falls at or below the first threshold, none of your SSDI is taxable. If it exceeds the first threshold, the IRS taxes the lesser of two amounts: either 50 percent of the excess over the threshold, or 50 percent of your total SSDI benefits. Whichever is smaller is the taxable amount.

The second threshold is $34,000 for single filers and $44,000 for married filing jointly. If your combined income exceeds this second threshold, the calculation becomes more complex. You pay tax on the lesser of either 85 percent of your benefits or a formula that includes 85 percent of the excess over the second threshold plus 50 percent of the excess over the first threshold (capped at 50 percent of your benefits). In practice, this means up to 85 percent of your SSDI can become taxable if your other income is high enough.

Step-by-Step Calculation Using IRS Publication 915

The IRS provides a worksheet in Publication 915 that walks through the calculation in order. You start by listing your AGI from your tax return. Then you add nontaxable interest income. Then you add half of your SSDI benefits. That sum is your combined income.

Next, you subtract the first threshold ($25,000 or $32,000, depending on filing status). If the result is zero or negative, you stop—no SSDI is taxable. If it is positive, you multiply that excess by 50 percent. That is your tentative taxable amount under the first threshold.

Then you check the second threshold. You subtract $34,000 (or $44,000) from your combined income. If that result is positive, you perform a second calculation that yields a second tentative amount. You compare the two tentative amounts and add them together, but the total cannot exceed 85 percent of your SSDI benefits. The result is your taxable SSDI amount.

Most people do not perform this by hand. Tax software, including free IRS tools like IRS Free File, includes the worksheet and calculates it automatically once you enter your income and SSDI amount. A tax professional can also do this calculation.

How State Taxes Treat SSDI

Federal taxation and state taxation of SSDI are separate. Most states do not tax SSDI at all. However, a small number of states—including Colorado, Connecticut, Kansas, Minnesota, Missouri, Montana, Nebraska, New Mexico, Rhode Island, Utah, and Vermont—tax SSDI under their own rules.

State thresholds and calculations differ from federal ones. Some states use the same federal combined income test; others use different thresholds or exclude SSDI entirely for residents over a certain age. Colorado, for example, excludes SSDI from state taxable income for residents age 55 and older. Connecticut taxes SSDI only if your federal adjusted gross income exceeds $50,000 (single) or $60,000 (married filing jointly).

If you live in a state that taxes SSDI, your state tax return instructions or a state tax professional can clarify the rules. The federal calculation does not automatically determine your state liability.

When You Must File a Tax Return

You must file a federal tax return if your gross income exceeds the standard deduction for your filing status and age. For 2024, the standard deduction is $14,600 for single filers under 65 and $18,350 for single filers 65 and older. For married couples filing jointly, it is $29,200 (both under 65) and higher if one or both are 65 or older.

SSDI counts toward this threshold. If you have $15,000 in SSDI and no other income, you exceed the standard deduction for a single filer under 65 and must file. However, if you have SSDI and no other income, you will owe no tax because your income is not above the threshold for taxation of benefits.

Even if you are not required to file, you may want to file anyway if you had income tax withheld or if you are may have access to to a refundable tax credit such as the Earned Income Tax Credit (EITC). Some people receiving SSDI also work part-time and may may have access to for the EITC, which requires filing to claim.

Common Scenarios and Examples

Scenario 1: SSDI only, no other income. You receive $1,200 per month in SSDI ($14,400 per year) and have no wages, interest, or other income. Your combined income is $7,200 (half of $14,400). This is well below the $25,000 threshold. You owe no federal tax on your SSDI. You may still need to file if your SSDI alone exceeds the standard deduction.

Scenario 2: SSDI plus part-time wages. You receive $1,200 per month in SSDI ($14,400 per year) and earn $12,000 from part-time work. Your combined income is $7,200 (half SSDI) plus $12,000 (wages) = $19,200. This is below the $25,000 threshold. No SSDI is taxable. You file because your total income exceeds the standard deduction, but you owe tax only on the $12,000 in wages.

Scenario 3: SSDI plus pension and interest. You receive $1,200 per month in SSDI ($14,400 per year), a $20,000 annual pension, and $3,000 in taxable interest. Your combined income is $7,200 (half SSDI) plus $20,000 (pension) plus $3,000 (interest) = $30,200. This exceeds the $25,000 threshold by $5,200. You multiply $5,200 by 50 percent = $2,600. This is your tentative taxable amount under the first threshold. You check the second threshold: $30,200 is below $34,000, so the second threshold does not explore. Your taxable SSDI is $2,600. You report this on your tax return and pay tax on it at your marginal rate.

Frequently Asked Questions

Do I have to pay tax on all of my SSDI if my income is high?

No. The maximum taxable portion of SSDI is 85 percent of your benefits, even if your combined income is very high. If you receive $1,200 per month, no more than $1,020 per month can be taxed, no matter how much other income you have.

Does SSDI count as earned income for the Earned Income Tax Credit?

No. SSDI is not earned income. If you work part-time and also receive SSDI, only your wages count toward the EITC. However, you may still be may have access to to the credit based on your wages alone.

What if I receive SSDI and also have nontaxable municipal bond interest?

The municipal bond interest counts toward your combined income for the SSDI tax test, even though you do not report it as taxable income. This can push you over a threshold and make some of your SSDI taxable, even though the bond interest itself is tax-free.

Can I reduce my SSDI taxes by spreading income across two years?

Not in most cases. The combined income test is calculated year by year. You cannot defer income to a future year to lower your current-year SSDI tax. However, if you have control over the timing of certain income—such as when you realize a capital gain—you may be able to plan around the thresholds with a tax professional's help.

Who calculates my SSDI tax if I use tax software?

The software does. Once you enter your SSDI amount and your other income, the program applies the IRS worksheet automatically and tells you how much of your SSDI is taxable. You do not need to do the math yourself.