The supplemental pay pay or tax rate is not set up properly (Setup, Pays, or Setup/Taxes, Tax Rates).

There are non-supplemental wages and pretax deductions on the check.

There are non-supplemental wages which would calculate a tax amount of 0.

There is an automatic pay which is not using the supplemental check box on the pay setup.

Verify your supplemental pay and tax setup. For more information, see the link below. If the setup is correct and the tax is still not calculating the correct amount, review the following:

1. If the employee's check includes any deductions marked as Before employee/employer taxes in the Deduction Setup window, Payroll prorates the deduction across the non-supplemental and supplemental wages. For example, an employee earns gross wages of $6000. His non-supplemental wages equal $1000, and his supplemental wages equal $5000. The employee has a 401(k) deduction of $500. The employee's supplemental and non-supplemental taxable amounts calculate as follows:

   Supplemental taxable 5000 - (5000/6000*500) = 4583.33
   Non-supplemental taxable 1000 - (1000/6000*500) = 916.66

2. If the employee's check includes both supplemental wages and non-supplemental wages and the non supplemental wages would calculate 0 for the tax, then the normal tax calculation is used to calculate the tax amount. To correct, enter separate checks for the supplemental and non-supplemental wages.

3. When processing the Other pay (ie Bonus), there is another automatic Other Pay type pay which calculated on this check. If that Other Automatic Pay type pay does not have the Supplemental Check box selected, the Other Pay type pay with the Supplemental Check box selected calculates a different tax percentage. Review the setup of the other automatic Other Pay type pay and either select the Supplemental check box, or have this pay process onto a different check for this pay period.