Withholding Taxes: Wisconsin

Federal law and guidance on this subject should be reviewed together with this section.

Author: Vicki M. Lambert, The Payroll Advisor

Summary

• All wages paid to Wisconsin residents are subject to Wisconsin withholding regardless of where the employee works. Certain Wisconsin residents who work in Minnesota are not subject to Wisconsin income tax withholding. All wages paid to nonresidents for services performed in Wisconsin are subject to Wisconsin withholding, with some exceptions. Wisconsin has reciprocal tax agreements in effect with Illinois, Indiana, Kentucky and Michigan. See Withholding on Residents, Nonresidents and Expatriates.
• Wisconsin Form WT-4 must be used to determine Wisconsin income tax withholding. Under certain circumstances, an employer may have to submit an employee's form to the Wisconsin Department of Revenue. See Employee Withholding Forms.
• Employers may determine withholding on supplemental wages either by treating the total of the supplemental and regular wages as a single wage payment for the regular payroll period, or by estimating the employee's annual gross salary and applying a flat percentage to the supplemental payments. See Supplemental Wages.