The Basic Formula for Taxable SSDI

Whether you pay taxes on SSDI depends on your combined income—a specific number that combines your SSDI with other income sources. The IRS uses this combined income to decide if any of your benefits are taxable. You calculate it by adding half of your annual SSDI benefits to all your other income (wages, interest, dividends, pensions, and other sources).

Once you have that combined income number, you compare it to two thresholds set by the IRS. If your combined income stays below the first threshold, you pay no tax on SSDI. If it crosses into the second threshold, up to 85 percent of your benefits may be taxable. Most people fall somewhere in between, where a smaller portion becomes taxable.

The thresholds are the same every year and do not adjust for inflation. For a single filer in 2024, the first threshold is $25,000 and the second is $34,000. For married couples filing jointly, the thresholds are $32,000 and $44,000. If you are married but file separately, the thresholds are much lower—usually $0 and $9,000.

Key Takeaways

  • Combined income means half your SSDI plus all your other income added together, and this number determines whether any benefits are taxable.
  • If your combined income is below $25,000 (single) or $32,000 (married filing jointly), you owe no tax on SSDI.
  • The IRS thresholds have not changed since 1984, so more people become taxable each year as their income rises with inflation.
  • You calculate taxable SSDI in two steps: first find the amount above the first threshold, then explore a formula that may tax up to 85 percent of your benefits.
  • Social Security sends Form SSA-1099 in January showing your annual benefits, which you need to complete your tax return.

Step One: Calculate Your Combined Income

Start by gathering your income for the full tax year. You need your total SSDI benefits received (Social Security will send this on Form SSA-1099 in January), plus all wages from work, interest from savings accounts, dividends from investments, distributions from retirement accounts, rental income, and any other income reported to the IRS.

Add half of your annual SSDI to all of that other income. That sum is your combined income. For example, if you received $18,000 in SSDI and earned $15,000 in wages, your combined income is $24,000 (half of $18,000 is $9,000, plus $15,000 in wages).

Do not include Supplemental Security Income (SSI), which is a different program. Do not include certain railroad retirement benefits or veterans' benefits if they are not taxable. If you are unsure whether a particular income source counts, the IRS Publication 915 lists what to include.

Step Two: Compare to the IRS Thresholds

Once you know your combined income, compare it to the thresholds for your filing status. If you are single and your combined income is $25,000 or less, you stop here—none of your SSDI is taxable. If you are married filing jointly and your combined income is $32,000 or less, the same applies.

If your combined income exceeds the first threshold but stays below the second threshold, you move to the calculation in the next section. If your combined income exceeds the second threshold ($34,000 for single filers, $44,000 for married filing jointly), you will use a different formula that can tax up to 85 percent of your benefits.

The thresholds are the same whether you are retired, disabled, or a survivor receiving benefits on someone else's record. They also do not change year to year, which means that as your other income grows, you are more likely to cross into a taxable range.

Calculating Taxable SSDI Between the Two Thresholds

If your combined income falls between the first and second threshold, use this two-step calculation. First, subtract the first threshold from your combined income. For a single filer with combined income of $28,000, you would subtract $25,000, leaving $3,000.

Next, take the smaller of two numbers: either half of that difference ($1,500 in the example above), or half of your total SSDI benefits for the year. Whichever is smaller is the amount of SSDI that becomes taxable. In this example, if your SSDI was $18,000, half would be $9,000. Since $1,500 is smaller, $1,500 of your SSDI is taxable.

This formula means that people in the middle range typically pay tax on only a small portion of their benefits. The tax itself depends on your overall tax bracket, so a taxable SSDI amount does not mean you owe the same percentage as someone in a higher income bracket.

When Up to 85 Percent of SSDI Becomes Taxable

If your combined income exceeds the second threshold, the calculation is more complex and can result in up to 85 percent of your benefits being taxable. The IRS uses a two-tier formula: it first calculates how much would be taxable using the method above, then adds an additional amount based on how far your combined income exceeds the second threshold.

For a single filer with combined income of $40,000, you would be $6,000 above the second threshold of $34,000. The formula takes 85 percent of that excess ($5,100) and adds it to the amount calculated from the first tier. The result cannot exceed 85 percent of your total SSDI benefits.

Most people do not reach this level unless they have substantial other income—a pension, ongoing wages, or significant investment returns. If you are in this situation, a tax professional or the IRS Publication 915 can walk you through the full calculation, or you can use the IRS worksheet.

Using IRS Publication 915 and Tax Software

The IRS publishes Publication 915, a free guide that includes worksheets to calculate taxable SSDI. You can read it from IRS.gov or request a printed copy. The publication walks through each scenario and provides examples for different income levels.

Most tax software (TurboTax, H&R Block, TaxAct, and others) will ask you to enter your SSDI amount from Form SSA-1099 and your other income, then automatically calculate the taxable portion. This is often the fastest and most accurate method if you are filing on your own.

If you work with a tax preparer or CPA, bring your Form SSA-1099 and a list of all other income sources. They will handle the calculation as part of preparing your return. Many tax preparation services offer free filing for people with lower incomes through the IRS Free File program.

Why the Thresholds Matter Year to Year

The two thresholds—$25,000 and $34,000 for single filers—have remained the same since 1984. Because they do not adjust for inflation, more people cross into the taxable range each year as their income grows. Someone who earned $20,000 in other income in 1984 was well below the threshold; today, that same income level puts many people into the taxable range.

This means that even if your SSDI and other income stay exactly the same, you may owe tax one year when you did not the previous year, straightforward because the thresholds have not moved. It also means that small increases in other income—a raise, a part-time job, or higher investment returns—can push you from non-taxable to taxable.

If you are close to a threshold, even a few hundred dollars in additional income can change whether you owe tax. This is worth considering if you are deciding whether to take on extra work or realize investment gains in a particular year.

Frequently Asked Questions

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

Not necessarily. You only file if your total income (including any taxable SSDI) exceeds the standard deduction for your age and filing status. For 2024, the standard deduction for a single person age 65 or older is $20,550. If your combined income is below that, you typically do not have to file, even if some SSDI is technically taxable.

What if I worked part of the year and then started receiving SSDI?

Count all wages earned that year, plus all SSDI received that year. The timing does not matter—the IRS looks at the full calendar year. If you started SSDI in June, you count the full amount of SSDI for the year plus any wages from January through December.

Does my spouse's income count toward the threshold if we file separately?

If you are married and file separately, the thresholds are much lower ($0 and $9,000 instead of $32,000 and $44,000), and your spouse's income does not count. Filing separately is rarely advantageous for SSDI purposes and usually results in higher taxes overall.

Can I reduce my taxable SSDI by lowering my other income?

Yes, in some cases. If you are close to a threshold, reducing other income—by deferring a bonus, delaying a pension distribution, or timing investment sales differently—can lower your combined income and reduce or eliminate taxable SSDI. A tax professional can help you plan this if it applies to your situation.

Where do I report taxable SSDI on my tax return?

You report it on Form 1040, lines 5a and 5b. Line 5a shows your total SSDI from Form SSA-1099, and line 5b shows the taxable portion you calculated. The instructions for Form 1040 and Publication 915 both explain how to fill these lines.