A corrected W-2 after filing arrives as Form W-2c, which lists each changed box twice: as previously reported and as correct. The form's own notice says that if the corrected amounts change the employee's income tax, the employee files Form 1040-X with Copy B of the W-2c. Name-only fixes usually change nothing on the return.
What is a W-2c and why do employers issue a corrected W-2 after filing?
Form W-2c, the Corrected Wage and Tax Statement, is the form an employer uses to fix a W-2 it already filed with the Social Security Administration and gave the employee. It shows only the boxes being corrected. Employers issue one after the employee has filed when a payroll error, a late adjustment or an identity error comes to light.
The IRS page About Form W-2c (reviewed 25 June 2026) says the form is used to "correct errors on Form W-2" filed with the SSA and to "provide corrected Form W-2 ... to employees." The current form is Form W-2c (Rev. 1-2026).
The General Instructions for Forms W-2 and W-3 (2026) describe the situations a W-2c handles. They include correcting only the employee's name or Social Security number, an incorrect tax year or employer identification number, and duplicate W-2s filed for one employee under one EIN. They also describe specific money corrections, such as an employee repaying wages received in a prior year. The form has its own box for identity fixes: box e, "Corrected SSN and/or name," with boxes f and g for the previously reported number and name.
Timing is what makes a W-2c awkward. An employer may find an error weeks or months into the year, after most employees have filed. A client who filed in February and receives a W-2c in June often forwards it without comment, sometimes assuming it is a duplicate. It is not a duplicate. A W-2c replaces specific figures on the original, and the firm has to decide whether the return those figures fed now needs to change.
Which W-2c box changes affect tax owed?
The W-2c box changes that most directly affect tax owed are Box 1, wages, tips and other compensation, and Box 2, federal income tax withheld. Changes to Social Security and Medicare boxes can matter in narrower ways, and a corrected name or Social Security number alone usually changes no figure on the return.
The W-2 instructions define the boxes. Box 1 is wages, tips and other compensation. Box 2 is federal income tax withheld. Box 3 is Social Security wages and Box 4 Social Security tax withheld. Box 5 is Medicare wages and tips and Box 6 Medicare tax withheld. Boxes 15 through 17 carry state information, and 18 through 20 local information.
Boxes 1 and 2
A change to Box 1 changes the wage figure on the return. A change to Box 2 changes the withholding credited against tax. Either one changes the balance due or the refund. The Notice to Employee printed on Form W-2c says: "If the corrected amounts change your U.S. income tax, file Form 1040-X with Copy B of this Form W-2c to amend the return you already filed."
Boxes 3 through 6
Social Security and Medicare wages are the base for payroll tax, which the employer withholds. A change there corrects the employee's earnings record, and it may not move the income tax figure. One exception is printed on the W-2c itself: "If there is a correction in box 5, Medicare wages and tips, use the corrected amount to determine if you need to file or amend Form 8959," the Additional Medicare Tax form.
Name and Social Security number only
A W-2c that checks box e and fills boxes f and g corrects identity, not money. The form's note says employers should "only complete money fields that are being corrected," so a name-only W-2c has blank money boxes. The return's figures stand, though the client's file should hold the W-2c beside the original.
Comparing the original and corrected W-2 figures before amending
Comparing the original and corrected W-2 figures means reading each money box on the W-2c in its two columns, "Previously reported" and "Correct information," and checking the previously reported figure against what the filed return actually used. The difference between the columns, not the corrected figure alone, is what changes the return.
Form W-2c prints every money box in pairs. Box 1 under "Previously reported" sits next to Box 1 under "Correct information," and the same for Box 2 and the rest. The first check is that the previously reported figure matches the W-2 the firm used. If it does not, the firm may have entered a different W-2 or a Form 4852 estimate, and the comparison has to start from the return, not the form.
The second check is whether the change is in a box that feeds the return. Use the previous section: Boxes 1 and 2 almost always do, Box 5 can through Form 8959, and identity boxes do not.
A worked W-2c with Box 1 and Box 2 changes
This example is fictional. The employee is Priya Natarajan, a client of an example firm; the employer is Example Robotics Inc. Her tax year 2026 return was filed in March 2027. In June 2027 the employer issued a W-2c because a bonus paid in December 2026 had been left out of payroll's year-end file. All amounts are example values.
| W-2c box | Previously reported | Correct information | Change |
|---|---|---|---|
| 1, Wages, tips, other compensation | $54,000 | $57,200 | +$3,200 |
| 2, Federal income tax withheld | $5,400 | $5,900 | +$500 |
| 3, Social security wages | $54,000 | $57,200 | +$3,200 |
| 5, Medicare wages and tips | $54,000 | $57,200 | +$3,200 |
The filed return used $54,000 of wages and $5,400 of withholding, so the previously reported column matches. The return now understates wages by $3,200 and understates withholding by $500.
To see the effect, assume for illustration only that the added wages fall entirely in a 22% bracket. The extra tax would be $3,200 × 22% = $704. The extra withholding is $500. The net effect is $204 more owed on the amended return in this illustration. The real figure depends on the client's full return, which the amended return refigures.
The decision follows the W-2c's own notice: the corrected amounts change income tax, so Priya files Form 1040-X with Copy B of the W-2c. The Instructions for Form 1040-X (Revised 12/2025) say to attach copies of any corrected Forms W-2 received after the original return, and that Form 1040-X can be filed electronically. The mechanics of preparing the amended return are the same as for any corrected information return, and the post on a corrected 1099 after filing covers filing Form 1040-X step by step.
Had the W-2c moved Box 2 alone, upward, the return would show an overpayment, and the amended return becomes a refund claim with its own time limit. The post on a corrected 1099 sets out when an amended return is needed and the refund-claim window.
Edge case: an employer that will not issue a corrected W-2
When an employer will not issue a corrected W-2, the employee follows the IRS steps for a wrong W-2: contact the employer, call the IRS if nothing arrives by the end of February, and file Form 4852, which can substitute for a W-2c. Keep every record of the correct figures and of each request.
IRS Topic 154, what to do if a Form W-2 or Form 1099-R is missing or incorrect (reviewed 24 September 2026), covers wrong forms as well as missing ones, and the IRS call works the same way for both. The post on a missing W-2 sets out when the IRS steps in and what the call needs.
The IRS page About Form 4852 (reviewed 19 August 2026) says the form "serves as a substitute for Form W-2, Form W-2c, and Form 1099-R" and is used when the employer issued an incorrect W-2. Form 4852 (Rev. September 2020) asks on line 9 how the amounts were determined and on line 10 for the efforts made to get the W-2 or W-2c from the employer.
Records to keep
- The original W-2 and any W-2c the employer did issue.
- The final pay stub of the year, which shows year-to-date wages and withholding.
- Any bonus, severance or benefit statement that explains the difference.
- Dated emails or letters asking the employer for a correction, and any replies.
- Notes of calls to the IRS, with the date.
A related case is a return already filed on Form 4852 when the real W-2 later arrives with different numbers. The post on what to do when a client's W-2 never arrives covers that sequence. The IRS wage and income transcript is another check on what the employer filed; the post on the IRS wage and income transcript for missing forms explains what it shows and leaves out.
When does a corrected W-2 also change the state return?
A corrected W-2 changes the state return when the W-2c corrects Box 16, state wages, or Box 17, state income tax withheld. Form W-2c has a separate "State Correction Information" block with previously reported and correct columns for those boxes. A state change usually needs its own state amendment, filed under the state's rules.
Form W-2c (Rev. 1-2026) prints the state block below the federal boxes, with Box 15 for the state and the employer's state ID number, Box 16 for state wages, tips and other compensation, and Box 17 for state income tax. A "Locality Correction Information" block does the same for Boxes 18 through 20. Read the state block on its own: a W-2c can change Box 1 without changing Box 16, or the other way round, depending on how the error arose.
The 1040-X instructions note that a change to the federal return may also require a change to the state return. Each state sets its own amended-return form and process, which this post does not cover. For the client file, the point is that one W-2c can lead to two amendments, and the state one is easy to forget when the federal change drew all the attention.
A W-2c can also travel with other late paper. A client whose Marketplace form changes in the same summer faces a separate question with different rules, covered in the post on a missing 1095-A and the Marketplace form.
A corrected form that arrives months after filing is easy to file away as a copy. Schema CPA sorts every page a client uploads by document type, issuer and period, so a June arrival from Example Robotics sits under that employer and tax year next to the original, where a preparer can review it; the pricing section lists what each plan includes.