Caution:

This computational bridge applies only for Forms W-4 that were in effect on or before December 31, 2019, and that continue in effect because an employee didn’t submit a 2020 or later Form W-4. If an employee is required, or chooses, to submit a new Form W-4, it doesn’t change the requirement that the employee must use the current year’s revision of Form W-4. Upon putting into effect a new Form W-4 from an employee, you must stop using this computational bridge for the applicable year of the new Form W-4. An employer using the computational bridge for a Form W-4 furnished by an employee must retain the Form W-4 for its records.

Lock-in letters.

The IRS may have notified you in writing that the employee must use a specific marital status and is limited to a specific number of allowances in a letter (commonly referred to as a “lock-in letter”) applicable before 2020. For more information about lock-in letters, see section 9 of Pub. 15. For lock-in letters based on 2019 or earlier Forms W-4, you may use this optional computational bridge to comply with the requirement to withhold based on the maximum withholding allowances and filing status permitted in the lock-in letter.

Nonresident alien employees.

You may use this computational bridge to convert a nonresident alien employee’s 2019 or earlier Form W-4 to a 2020 or later Form W-4. However, for the second adjustment of the computational bridge, always enter $4,300 in Step 4(a) on a 2020 or later Form W-4. If you convert a nonresident alien employee’s 2019 or earlier Form W-4 to a 2020 or later Form W-4, be sure to use Table 2 when adding an amount to their wages for figuring federal income tax withholding. See Withholding Adjustment for Nonresident Alien Employees , later, for more information.

For more information, see Treasury Decision 9924, 2020-44 I.R.B. 943, available at IRS.gov/irb/2020-44_IRB#TD-9924 .