The basic test: your combined income

Whether you owe federal income tax on your SSDI depends on your combined income — a specific number that includes your SSDI benefits plus other money you received that year. The IRS calls this "combined income," and it's the only number that matters for this decision.

Combined income is calculated as: your adjusted gross income (AGI) plus nontaxable interest plus half of your Social Security benefits (including SSDI). If your combined income stays below a certain threshold, you owe no federal tax on your SSDI. If it goes above that threshold, some of your benefits become taxable.

The threshold depends on your filing status. For a single filer, the threshold is $25,000. For married filing jointly, it's $32,000. For married filing separately, it's $0 — meaning any combined income at all can trigger taxation. These thresholds have not changed since 1984.

Key Takeaways

  • Combined income is the only number that determines whether your SSDI is taxable, and it includes half your SSDI benefits plus all other income you received.
  • If you are single and your combined income is under $25,000, your SSDI is not taxable; married filing jointly filers have a $32,000 threshold.
  • You can calculate your combined income yourself using a worksheet from IRS Publication 915, or ask a tax preparer to do it.
  • If your combined income is above the threshold, the IRS has a two-tier formula that determines what percentage of your benefits become taxable — never more than 85 percent.

How to calculate your combined income yourself

Start with your adjusted gross income (AGI) for the year. This is the number at the bottom of the income section of your tax return — the total of all wages, self-employment income, interest, dividends, and other taxable income, minus certain deductions like educator expenses or student loan interest.

Add to that number any nontaxable interest you received. This includes interest from municipal bonds and certain other tax-exempt bonds. If you received no nontaxable interest, this step adds zero.

Then add half of your total Social Security and SSDI benefits for the year. If you received $15,000 in SSDI, you add $7,500 to this calculation. The result is your combined income.

The IRS provides a worksheet in Publication 915 (Social Security Benefits) that walks through this calculation step by step. You can read it free from irs.gov. If the math feels uncertain, a tax preparer or your local IRS office can walk you through it.

What happens if your combined income exceeds the threshold

If your combined income is above the threshold for your filing status, some of your SSDI becomes taxable. The IRS uses a two-tier formula to calculate exactly how much.

In the first tier, you take the smaller of two numbers: either the amount your combined income exceeds the threshold, or $9,000 (for single filers) or $12,000 (for married filing jointly). You then take 50 percent of that number. This is your "tier one" taxable amount.

If your combined income is still higher, you move to the second tier. You take the amount your combined income exceeds $34,000 (for single filers) or $44,000 (for married filing jointly), and take 85 percent of that number. You add this to your tier one amount. This is your total taxable SSDI.

The result is never more than 85 percent of your total benefits. Publication 915 includes a detailed worksheet for this calculation as well. Many tax software programs calculate it automatically if you enter your SSDI amount.

When to use a tax preparer instead

If you have other income sources — wages, self-employment income, rental income, investment income, or pensions — the calculation becomes more complex because each type of income affects your AGI differently. A tax preparer can account for deductions and credits you might miss on your own.

If you are married filing jointly and your spouse also receives Social Security or SSDI, the combined income calculation includes both of your benefits, which adds another layer. A preparer can make sure both spouses' income is counted correctly.

If you are unsure whether you need to file a tax return at all, a preparer can tell you. Some people with SSDI as their only income do not have to file, but others do depending on their age and filing status. The IRS website has a tool called the "IRS Interactive Tax Assistant" that can help you determine this.

State taxes and SSDI

Federal tax rules do not explore to state income tax. Most states do not tax SSDI at all, regardless of your combined income. However, a few states — including Colorado, Connecticut, Kansas, Minnesota, Missouri, Montana, Nebraska, New Mexico, Rhode Island, Utah, and Vermont — tax some or all Social Security benefits under their own rules.

If you live in one of these states, contact your state tax authority or a local tax preparer to find out whether your SSDI is taxable under state law. The rules vary by state and do not always match the federal thresholds.

What to do if you already paid tax on your SSDI

If you had taxes withheld from your SSDI payments and later discovered you did not actually owe tax on those benefits, you can file a tax return to claim a refund. You have three years from the date you filed your return (or two years from the date you paid the tax, whichever is later) to claim the refund.

If you did not file a tax return in a year when you should have, you can still file a late return to claim a refund. The IRS does not penalize you for filing late if you are owed a refund.

If you want to stop having taxes withheld from your SSDI going forward, you can request a change using Form W-4V (Voluntary Withholding Request). You can submit this form to your local Social Security office or online through your my Social Security account.

Frequently Asked Questions

Do I have to file a tax return if SSDI is my only income?

Not always. If your combined income is below the threshold for your filing status and you have no other filing requirement, you do not have to file. However, if you had taxes withheld from your SSDI, filing a return may get you a refund. The IRS Interactive Tax Assistant on irs.gov can tell you whether you must file.

What if I have a spouse who works but I only receive SSDI?

Your spouse's wages count toward your household's combined income for the purpose of determining whether your SSDI is taxable. If you file jointly, both of your incomes are added together. A tax preparer can help you understand whether filing jointly or separately makes sense for your situation.

Does my SSDI count as income for other programs like Medicaid or food stamps?

Yes, but those programs use different rules than the IRS. Medicaid, SNAP, and other means-tested programs count your gross SSDI amount as income, not the taxable portion. Contact your state Medicaid office or local SNAP office to learn how your benefits affect your status in those programs.

Can I reduce my combined income to avoid taxes on my SSDI?

You can reduce your AGI through certain deductions — for example, contributing to a traditional IRA, claiming the standard deduction, or deducting business expenses if you are self-employed. A tax preparer can review your situation and suggest deductions you may have missed. However, you cannot reduce the SSDI itself.