When Should You File Form 941-X?

File Form 941-X when you discover an error on a previously filed Form 941.

However, if your only errors on Form 941 relate to the number of employees who received wages (Form 941, line 1) or to federal tax liabilities reported on Form 941, Part 2, or on Schedule B (Form 941), Report of Tax Liability for Semiweekly Schedule Depositors, don’t file Form 941-X. For more information about correcting federal tax liabilities reported on Form 941, Part 2, or on Schedule B (Form 941), see the Instructions for Schedule B (Form 941).

Due dates. The due date for filing Form 941-X depends on when you discover an error and if you underreported or overreported tax. If you underreported tax, see Underreported tax, later. For overreported tax amounts, you may choose to either make an interest-free adjustment or file a claim for refund or abatement. If you’re correcting overreported tax amounts, see Overreported tax—Adjustment process or Overreported tax—Claim process , later.

If any due date falls on a Saturday, Sunday, or legal holiday, you may file Form 941-X on the next business day. If we receive Form 941-X after the due date, we will treat Form 941-X as filed on time if the envelope containing Form 941-X is properly addressed, contains sufficient postage, and is postmarked by the U.S. Postal Service (USPS) on or before the due date, or sent by an IRS-designated private delivery service (PDS) on or before the due date. If you don’t follow these guidelines, we will consider Form 941-X filed when it is actually received. See Pub. 15 for more information on legal holidays. For more information about PDSs, see Where Should You File Form 941-X , later.

Underreported tax. If you’re correcting underreported tax, you must file Form 941-X by the due date of the return for the return period in which you discovered the error and pay the amount you owe by the time you file . Doing so

6 Instructions for Form 941-X (Rev. 4-2026)

will generally ensure that your correction is interest free and not subject to failure-to-pay (FTP) or failure-to-deposit (FTD) penalties. See What About Penalties and Interest, later. For details on how to make a payment, see the instructions for line 27, later.

If Form 941-X is filed late (after the due date of the return for the return period in which you discovered the error), you must attach an amended Schedule B (Form 941) to Form 941-X. Otherwise, the IRS may assess an “averaged” FTD penalty. See “Averaged” FTD penalty in section 11 of Pub. 15 for more information about “averaged” FTD penalties. The total tax reported on the “Total liability for the quarter” line of Schedule B (Form 941) must match the corrected tax (Form 941, line 12, combined with any correction entered on Form 941-X, line 23) for the quarter, less any previous abatements and interest-free tax assessments.

If you discover an error in... Form 941-X is due...

1. January, February, March April 30 2. April, May, June July 31 3. July, August, September October 31 4. October, November, December January 31

The dates shown in the table above apply only to corrections of underreported amounts. If any due date falls on a Saturday, Sunday, or legal holiday, you may file Form 941-X on the next business day.

Example—You owe tax. On May 15, 2026, you discover that you underreported $10,000 of social security and Medicare wages on your 2026 first quarter Form 941. File Form 941-X and pay the amount you owe by July 31, 2026, because you discovered the error in the second quarter of 2026, and July 31, 2026, is the due date for that quarter. If you file Form 941-X before July 31, 2026, pay the amount you owe by the time you file.

Tip: The due date for filing the adjusted return is determined by the type of return (Form 941 or Form 944) being corrected, without regard to your current filing requirements. Therefore, if you’re currently filing Form 941 and you’re correcting a previously filed Form 944, you must file Form 944-X by January 31 of the year following the year you discover the error.

Overreported tax—Adjustment process. If you overreported tax on Form 941 and choose to apply the credit to Form 941 or Form 944, file an adjusted return on Form 941-X soon after you discover the error but more than 90 days before the period of limitations on the credit or refund for Form 941 expires. See Is There a Deadline for Filing Form 941-X, later.

Overreported tax—Claim process. If you overreported tax on Form 941, you may choose to file a claim for refund or abatement on Form 941-X any time before the period of limitations on credit or refund expires on Form 941. If you also need to correct any underreported tax amounts, you must file another Form 941-X reporting only corrections to the underreported amounts. See Is There a Deadline for Filing Form 941-X? next.

Caution: You may not file a refund claim to correct federal income tax or Additional Medicare Tax actually withheld from employees.