Calculation Methods for Federal Income Tax

You can use these calculation methods for federal income tax (FIT).

Calculation method	Run type	Calculate on period-to-date amount	What it does
Default	Regular	No	Takes the wages in a regular run. Calculates the tax, independent of how many regular runs are in a pay period.
Default	Regular	Yes	Takes the wages in all the regular runs for the period. Calculates the tax.
Aggregation	Supplemental	N/A	Takes the wages in all the regular and supplemental runs for the period. Calculates the tax.
Cumulative Aggregation	Supplemental	N/A
Flat Percentage	Supplemental	N/A	This is the default method for supplemental payroll runs. The payroll process applies the appropriate flat percentage as set by the IRS.