Updated October 17, 2026. Quick answer: Boxes 15, 16 and 17 of Form W-2 hold your state’s abbreviation and your employer’s state ID number, your state wages, and the state income tax withheld. They concern every employee whose pay is reported to a state. The IRS form is clear that the details belong to the state: its instructions tell the employer to contact the state for specific reporting information, so your state’s own return instructions explain where these amounts go.
What boxes 15, 16 and 17 report
Three boxes on the right side of the form are the state group. The labels printed on Form W-2 are:
| Box | Label printed on the form |
|---|---|
| Box 15 | The state, and the “Employer’s state ID number” |
| Box 16 | “State wages, tips, etc.” |
| Box 17 | “State income tax” |
The employer-side instructions describe the group like this: “Use these boxes to report state and local income tax information.” “Enter the two-letter abbreviation for the name of the state.” So the state you see in box 15 should be a two-letter abbreviation, not a spelled-out name.
These boxes sit in the same band of the form as the local boxes, which have their own page. The whole run of boxes from 10 to 20 is laid out in the W-2 boxes 10 to 20 guide.
The employer’s state ID number
Box 15 has two parts, the state and a number beside it. On the form the second part is labelled “Employer’s state ID number”. Who issues that number is stated in one sentence: “The employer’s state ID numbers are assigned by the individual states.”
In plain terms, the number is the employer’s state ID, and the instructions say the individual states assign it. It is separate from your Social Security number, which sits in its own box on the form. If the number looks wrong, the person who can fix it is the employer, because the number is the employer’s record with the state.
State wages and state income tax
Box 16 is labelled “State wages, tips, etc.” and box 17 is labelled “State income tax”. The Form W-2 instructions for these boxes are one short paragraph, which closes with a pointer: “Contact your state or locality for specific reporting information.”
That sentence is why this page does not tell you how state wages are figured or what your state taxes. The federal form does not set your state’s rules, so when box 16 and box 1 do not match, the next step is the state tax agency’s guidance for your state, or a question to your payroll department. For the other money boxes in the same band, see the W-2 box 14 page and the box 10 dependent care page, which describe items that sometimes explain a difference.
Two states on one form, and a second form
Employees who worked in more than one state, or who moved during the year, can see more than one line in these boxes. The IRS puts the limit this way: “The state and local information boxes can be used to report wages and taxes for two states and two localities.” “Keep each state’s and locality’s information separated by the broken line.”
If more space is needed, the employer has a second option: “If you need to report information for more than two states or localities, prepare a second Form W-2.” A second form can therefore carry the additional lines. When you get two Forms W-2 from the same employer, look at box 15 on each before assuming something went wrong, and add the amounts the way your state’s instructions direct.
Which copy goes to the state
Form W-2 is printed in several copies, and the one for your federal return is labelled “To Be Filed With Employee’s FEDERAL Tax Return.” The copy meant for the state is a separate one: it is labelled “To Be Filed With Employee’s State, City, or Local Income Tax Return”.
Two pointers on this site help with how state tax interacts with the federal return. The state and local tax deduction limit is covered in the 2026 SALT cap page, and the schedule where itemized deductions are totaled is described on the Schedule A page. They are pointers only. Whether a state tax amount helps you at all on the federal return depends on those pages’ sources and on your own filing choices, not on box 17 by itself.
What to check on your own form
A short checklist from the form itself, using only what is printed on it. First, is the state abbreviation in box 15 the state where you lived and worked? Second, is the employer’s state ID number filled in? Third, does the state wage figure in box 16 look reasonable beside your last pay stub of the year, and is the state tax in box 17 close to the total of the state withholding lines on those stubs? A mismatch is not proof of an error, because states have their own rules, but it is a reason to ask payroll before you file.
If a number is wrong, the employer fixes it. The employee-side notice on the form says what to do for the identifying information: “If your name, SSN, or address is incorrect, correct Copies B, C, and 2 and ask your employer to correct your employment record.” Money amounts, including the state boxes, are corrected by the employer on a corrected form, so keep every version you are sent.
Edition and box numbers
The primary read for this page is the 2025 edition of Form W-2, the form an employee receives in early 2026 for tax year 2025, together with the 2025 General Instructions for Forms W-2 and W-3. The 2026 edition of both documents was the one irs.gov served as current on 2026-10-17, and it was compared line by line. The text on boxes 15 through 20 is the same in both editions. The 2026 instructions open the group with “Use these boxes to report state and local income tax information.”, and the 2026 form prints the label “State wages, tips, etc.”, the same words as the 2025 form. Check the tax year printed on the form you received, because the box numbers and the wording you see are those of that year’s edition.
Common mistakes
- Treating box 16 as a copy of box 1. The IRS text only says the boxes are for state information and adds “Contact your state or locality for specific reporting information.” Your state decides how its wages are figured.
- Throwing away a second Form W-2 from the same employer as a duplicate. The instructions say “If you need to report information for more than two states or localities, prepare a second Form W-2.”
- Using the federal copy for state filing without checking the state copy label. Copy 2 is the one labelled “To Be Filed With Employee’s State, City, or Local Income Tax Return”.
Related: the 2026 SALT cap, Schedule A (Form 1040), Form W-4, and the 2025 federal tax brackets.
Sources
- General Instructions for Forms W-2 and W-3 (2025): IRS archived PDF (irs.gov)
- Form W-2, Wage and Tax Statement (2025), with the Notice to Employee and Instructions for Employee: IRS archived PDF (irs.gov)
- General Instructions for Forms W-2 and W-3 (2026): https://www.irs.gov/pub/irs-pdf/iw2w3.pdf
- Form W-2, Wage and Tax Statement (2026), with the Notice to Employee and Instructions for Employee: https://www.irs.gov/pub/irs-pdf/fw2.pdf
Read from the IRS documents linked above on October 17, 2026. General information, not tax advice. Your own facts decide the outcome, and a preparer, the account provider or the IRS is the right place to confirm anything consequential.