Caution:

A Form W-4 that makes a change for the next calendar year won’t take effect in the current calendar year.

Successor employer.

If you’re a successor employer (see Successor employer , later in this section), secure new Forms W-4 from the transferred employees unless the “Alternative Procedure” in section 5 of Revenue Procedure 2004-53 applies. See Revenue Procedure 2004-53, 2004-34 I.R.B. 320, available at IRS.gov/irb/2004-34_IRB#RP-2004-53 .

IRS Tax Withholding Estimator for employees.

You may advise your employees to use the IRS Tax Withholding Estimator available at IRS.gov/W4App for help in determining how to complete their Forms W-4. An employee that makes a mid-year change to their withholding after using the IRS Tax Withholding Estimator may be underwithheld or overwithheld once their Form W-4 is applied to the next full calendar year. Therefore, you should remind employees that made a mid-year change to revisit the IRS Tax Withholding Estimator in early January and submit a new Form W-4 for the year.

Completing Form W-4.

The amount of any federal income tax withholding must be based on filing status, income (including income from other jobs), deductions, and credits. Your employees may not base their withholding amounts on a fixed dollar amount or percentage. However, an employee may specify a dollar amount to be withheld each pay period in addition to the amount of withholding based on filing status and other information reported on Form W-4.

Employees that are married filing jointly and have spouses that also currently work, or employees that hold more than one job at the same time, should account for their higher tax rate by completing Step 2 of their 2026 Form W-4. Employees also have the option to report on their 2026 Form W-4 other income they will receive that isn’t subject to withholding and other deductions they will claim in order to increase the accuracy of their federal income tax withholding.

See Pub. 505 for more information about completing Form W-4. Along with Form W-4, you may wish to order Pub. 505 for use by your employees.

Don’t accept any withholding or estimated tax payments from your employees in addition to withholding based on their Form W-4. If they require additional withholding, they should submit a new Form W-4 and, if necessary, pay estimated tax by filing Form 1040-ES or by making an electronic payment of estimated taxes. Employees who receive tips may provide funds to their employer for withholding on tips; see Collecting taxes on tips in section 6.

Exemption from federal income tax withholding.

Generally, an employee may claim exemption from federal income tax withholding because they had no income tax liability last year and expect none this year. See the Form W-4 instructions for more information. However, the wages are still subject to social security and Medicare taxes. See also Invalid Forms W-4 , later in this section.

A Form W-4 claiming exemption from withholding is effective when it is given to the employer and only for that calendar year. To continue to be exempt from withholding, an employee must give you a new Form W-4 by February 15. If the employee doesn’t give you a new Form W-4 by February 15, begin withholding as if they had checked the box for Single or Married filing separately in Step 1(c) and made no entries in Step 2, Step 3, or Step 4 of the 2026 Form W-4. If the employee provides a new Form W-4 claiming exemption from withholding on February 16 or later, you may apply it to future wages but don’t refund any taxes withheld while the exempt status wasn’t in place.

Withholding federal income taxes on the wages of nonresident alien employees.

In general, you must withhold federal income taxes on the wages of nonresident alien employees. However, see Pub. 515 for exceptions to this general rule. See section 5 for more guidance on H-2A visa workers.

Withholding adjustment for nonresident alien employees.

Nonresident aliens may not claim the standard deduction on their tax returns; therefore, employers must add an amount to the wages of nonresident alien employees performing services within the United States in order to figure the amount of federal income tax to withhold from their wages. The amount is added to their wages solely for calculating federal income tax withholding. The amount isn’t included in any box on the employee’s Form W-2 and doesn’t increase the income tax liability of the employee. The amount also doesn’t increase the social security tax or Medicare tax liability of the employer or the employee, or the FUTA tax liability of the employer. See Withholding Adjustment for Nonresident Alien Employees under Introduction in Pub. 15-T for the amount to add to their wages for the payroll period.

Supplemental wage payment.

The adjustment for determining the amount of income tax withholding for nonresident alien employees doesn’t apply to a supplemental wage payment (see section 7 ) if the 37% mandatory flat rate withholding applies or if the 22% optional flat rate withholding is being used to calculate income tax withholding on the supplemental wage payment.

Nonresident alien employee’s Form W-4.

When completing Forms W-4, nonresident aliens are required to:

Not claim exemption from income tax withholding (even if they meet both of the conditions to claim exemption from withholding listed in the Form W-4 instructions);

Request withholding as if they’re single, regardless of their actual filing status;

Not claim the child tax credit or credit for other dependents in Step 3 of Form W-4 (if the nonresident alien is a resident of Canada, Mexico, or South Korea, or a student from India, or a business apprentice from India, they may claim, under certain circumstances (see Pub. 519, U.S. Tax Guide for Aliens), the child tax credit or credit for other dependents); and

Write “Nonresident Alien” or “NRA” in the space below Step 4(c) of Form W-4.

If you maintain an electronic Form W-4 system, you should provide a field for nonresident aliens to enter nonresident alien status instead of writing “Nonresident Alien” or “NRA” in the space below Step 4(c) of Form W-4. You should instruct nonresident aliens to see Notice 1392, Supplemental Form W-4 Instructions for Nonresident Aliens, before completing Form W-4.

Form 8233.

If a nonresident alien employee claims a tax treaty exemption from withholding, the employee must submit Form 8233 with respect to the income exempt under the treaty, instead of Form W-4. For more information, see the Instructions for Form 8233 and Pay for Personal Services Performed under Withholding on Specific Income in Pub. 515.

IRS review of requested Forms W-4.

When requested by the IRS, you must make original Forms W-4 available for inspection by an IRS employee. You may also be directed to send certain Forms W-4 to the IRS. You may receive a notice from the IRS requiring you to submit a copy of Form W-4 for one or more of your named employees. Send the requested copy or copies of Form W-4 to the IRS at the address provided and in the manner directed by the notice. The IRS may also require you to submit copies of Form W-4 to the IRS as directed by a revenue procedure or notice published in the Internal Revenue Bulletin.

After submitting a copy of a requested Form W-4 to the IRS, continue to withhold federal income tax based on that Form W-4 if it is valid (see Invalid Forms W-4 , later in this section). However, if the IRS later notifies you in writing that the employee isn’t entitled to claim exemption from withholding or a claimed amount of deductions or credits, withhold federal income tax based on the effective date, employee’s permitted filing status, and withholding instructions specified in the IRS notice (commonly referred to as a “lock-in letter”).

Initial lock-in letter.

The IRS uses information reported on Form W-2 to identify employees with withholding compliance problems. In some cases, if a serious underwithholding problem is found to exist for a particular employee, the IRS may issue a lock-in letter to the employer specifying the employee’s permitted filing status and providing withholding instructions for the specific employee. You’ll also receive a copy for the employee that identifies the permitted filing status and provides a description of the withholding instructions you’re required to follow and the process by which the employee can provide additional information to the IRS for purposes of determining the appropriate withholding and/or modifying the specified filing status. You must furnish the employee copy to the employee within 10 business days of receipt if the employee is employed by you as of the date of the notice. You may follow any reasonable business practice to furnish the employee copy to the employee. Begin withholding based on the notice on the date specified in the notice.

Implementation of lock-in letter.

When you receive the notice specifying the permitted filing status and providing withholding instructions, you may not withhold immediately on the basis of the notice. You must begin withholding tax on the basis of the notice for any wages paid after the date specified in the notice. The delay between your receipt of the notice and the date to begin the withholding on the basis of the notice permits the employee time to contact the IRS.

Seasonal employees and employees not currently performing services.

If you receive a notice for an employee who isn’t currently performing services for you, you’re still required to furnish the employee copy to the employee and withhold based on the notice if any of the following apply.

You’re paying wages for the employee’s prior services and the wages are subject to income tax withholding on or after the date specified in the notice.

You reasonably expect the employee to resume services within 12 months of the date of the notice.

The employee is on a leave of absence that doesn’t exceed 12 months or the employee has a right to reemployment after the leave of absence.

Termination and rehire of employees.

If you must furnish and withhold based on the notice and the employment relationship is terminated after the date of the notice, you must continue to withhold based on the notice if you continue to pay any wages subject to income tax withholding. You must also withhold based on the notice or modification notice (explained next) if the employee resumes the employment relationship with you within 12 months after the termination of the employment relationship.

Modification notice.

After issuing the notice specifying the permitted filing status and providing withholding instructions, the IRS may issue a subsequent notice (modification notice) that modifies the original notice. The modification notice may change the permitted filing status and withholding instructions. You must withhold federal income tax based on the effective date specified in the modification notice.

New Form W-4 after IRS notice.

After the IRS issues a notice or modification notice, if the employee provides you with a new Form W-4 claiming complete exemption from withholding or a completed Form W-4 that results in less withholding than would result under the IRS notice or modification notice, disregard the new Form W-4. You must withhold based on the notice or modification notice unless the IRS notifies you to withhold based on the new Form W-4. If the employee wants to put a new Form W-4 into effect that results in less withholding than required, the employee must contact the IRS.

If, after you receive an IRS notice or modification notice, your employee gives you a new completed Form W-4 that results in more withholding than would result under the notice or modification notice, you must withhold tax based on the new Form W-4. Otherwise, disregard any subsequent Forms W-4 provided by the employee and withhold based on the IRS notice or modification notice.