Updated October 19, 2026. Quick answer: Publication 915 is the IRS guide to the federal income tax rules for Social Security benefits and the Social Security equivalent part of tier 1 railroad retirement benefits, and the web edition is for 2025 returns. It says that generally up to 50% of benefits will be taxable, and up to 85% in two situations.
Quick reference
| Item | As the IRS publication states it |
|---|---|
| Base amount, single, head of household, or qualifying surviving spouse (Base amount) | $25,000 |
| Base amount, married filing jointly (Base amount) | $32,000 |
| Base amount, married filing separately and lived with your spouse at any time during 2025 | $0 |
| Maximum taxable part, general rule (How Much Is Taxable?) | up to 50% |
| Maximum taxable part, higher situations (How Much Is Taxable?) | up to 85% |
| Total of one-half of benefits and other income that opens the 85% case (How Much Is Taxable?) | $34,000 ($44,000 if married filing jointly) |
What the publication covers
The introduction says “This publication explains the federal income tax rules for social security benefits and equivalent tier 1 railroad retirement benefits.” The IRS cover line reads “For use in preparing 2025 Returns”. It also says of the benefits “They don’t include Supplemental Security Income (SSI) payments, which aren’t taxable.”
Parts of the publication in plain words
- Are any of your benefits taxable: exclusions, figuring total income, the base amount, and who is taxed.
- Tax withholding and estimated tax, including rules for people living abroad and nonresident aliens.
- How to report your benefits on Form 1040 or 1040-SR, and how much is taxable.
- Examples with filled in worksheets.
- The lump sum election, and deductions related to your benefits.
- An appendix that explains each box on Forms SSA-1099, RRB-1099, SSA-1042S and RRB-1042S.
Worksheets inside it
- Worksheet A, A Quick Way To Check if Your Benefits May Be Taxable
- Worksheet 1, Figuring Your Taxable Benefits
- Worksheet 2, Figure Your Additional Taxable Benefits (From a Lump-Sum Payment for a Year After 1993)
- Worksheet 3, the same for a lump sum payment for a year before 1994
- Worksheet 4, Figure Your Taxable Benefits Under the Lump-Sum Election Method
On this site, the Social Security benefits worksheet and the taxability calculator work in the same area.
The figures that matter
The base amounts are listed under Base amount: “$25,000 if you are single, head of household, or qualifying surviving spouse;” and “$32,000 if you are married filing jointly; or” and “$0 if you are married filing separately and lived with your spouse at any time during 2025.”
On the share that can be taxed, the publication says “Generally, up to 50% of your benefits will be taxable.” It continues “However, up to 85% of your benefits can be taxable if either of the following situations applies to you.”
The first situation reads “The total of one-half of your benefits and all your other income is more than $34,000 ($44,000 if you are married filing jointly).”
On the quick check, the source describes Worksheet A with “This is a quick way to check whether some of your benefits may be taxable.”
On reporting, it says “Report your net benefits (the total amount from box 5 of all your Forms SSA-1099 and RRB-1099) on line 6a and the taxable part on line 6b.”
On filing, the source says “If the only income you received during 2025 was your social security or the SSEB portion of tier 1 railroad retirement benefits, your benefits generally aren’t taxable and you probably don’t have to file a return.”
Where to go next
The line by line reporting is on Form 1040 line 6a and 6b. The tax statements are explained at SSA-1099 and RRB-1099 boxes, and railroad retirement is explained at railroad retirement tier 1 and tier 2 taxation.
Where this comes from
The IRS page About Publication 915 opens with “Publication 915 explains the federal income tax rules for social security benefits and equivalent Tier 1 railroad retirement benefits.” It links the PDF and eBook editions and the earlier revisions of the publication.
This page describes the web edition of Publication 915 (2025), Social Security and Equivalent Railroad Retirement Benefits, as served on irs.gov on October 19, 2026. The IRS can revise a publication after we read it, and the IRS page controls. General information, not tax or legal advice.
Common mistakes
- Reading the 50% as a flat rate. The source says “Generally, up to 50% of your benefits will be taxable.”
- Comparing only Social Security to the base amount. The source says to use “To figure the total of one-half of your benefits plus your other income, use Worksheet A, discussed later.”
- Assuming a spouse with no benefits can be left out. The source says “Even if your spouse didn’t receive any benefits, you must add your spouse’s income to yours”.
- Treating every Supplemental Security Income payment as Social Security income. The introduction says SSI payments are not included in the benefits it covers.
Related: IRS publications by number, Social Security benefits worksheet, Form 1040 line 6a and 6b, SSA-1099 and RRB-1099 boxes explained, Social Security tax torpedo, Railroad retirement tier 1 and tier 2 taxation, and Form W-4V Social Security withholding.
Sources
- IRS, Publication 915 (2025), Social Security and Equivalent Railroad Retirement Benefits (irs.gov): https://www.irs.gov/publications/p915
- IRS, About Publication 915 (irs.gov): https://www.irs.gov/forms-pubs/about-publication-915
Read from the IRS pages linked above on October 19, 2026. General information, not tax or legal advice. The IRS publication and the instructions for your own form control, and your own facts decide the outcome.