The IRS has a dedicated webpage with instructions how use the Form. You start by downloading a spreadsheet, and populate the first three boxes: (1) pay frequency (2) the employee’s gross pay per paycheck (3) which version of the W-4 is being used. If you have a 2020 W-4 you will continue to complete the box on the left side of the spreadsheet. If you have a pre-2020 W-4 you will use the box on the bottom right of the spreadsheet. The spreadsheet will provide a dollar-figure to withhold per paycheck.
One caveat: we tried this spreadsheet on our end assuming that we had a married couple with one of the spouses earning $1,900 bi-weekly and no other considerations. If the 2019 W-4 had been used it is likely they would have completed the W-4 as married with two allowances. This results in weekly withholdings of $118 per year. With the 2020 W-4 only $98 is withheld per paycheck. Considering 2020 tax rates, we expect these people will owe $2,653. The new W-4 would result in owing an additional $5 while the old W-4 would result in an overpayment of $415. The new W-4 appears to result in a more accurate amount of withholdings. Employers should refer their employees to the IRS instructions if they have questions on how to complete the form or their Tax Withholding Estimator which has been updated for 2020.
The IRS also has a FAQ page that answers many questions on the new Form W-4 for both employees and employers.
If you have any questions please contact us at (603)224-2000.