Under some circumstances, an employer can withhold up to 65 percent of the noncustodial parent's disposable income. Income Withholding for Non-IV-D Cases.You may be exempt from Utah withholding requirements if you do business in Utah for 60 days or less in a calendar year and have Tax Commission approval. Child support is calculated using the gross monthly income of both parents and the number of overnights the child spends in each household. How to fill out the Utah Withholding Tax Guide and Instructions 2024? 1. Gather employee wage information. 2. Use this tool to estimate the federal income tax you want your employer to withhold from your paycheck. This is tax withholding. Our Utah retirement tax friendliness calculator can help you estimate your tax burden in retirement using your Social Security, 401(k) and IRA income. Complete Form W-4MN so your employer can withhold the correct Minnesota income tax from your pay.