2025 tax withholding

W-4 forms (employee withholding certificates)

Information regarding the Federal W-4 form can be found on the IRS website. Information for the Iowa W-4 form can be found on the State of Iowa website.

Please note that University of Iowa cannot provide individual guidance on completion of the W-4 or any related tax implications. We recommend that you contact your tax consultant with any questions you may have.

State of Iowa income tax withholding

The Iowa Department of Revenue issued new income tax withholding tables for 2025 as well as a revised Iowa W-4 form.  These revisions were done to accommodate changes to individual income tax required under Iowa Senate File 2442.  This law establishes a 3.80% flat tax rate on Iowa individual income beginning January 1, 2025.  More tax information as well as a withholding estimator can be found on the Iowa Department of Revenue site. 

State of Illinois income tax withholding

The State of Illinois withholding tax rate is 4.95%.

Federal income tax withholding

Federal tax withholding tables have changed for 2025 based on inflation. Please refer to the IRS Publication 15-T, Federal Income Tax Withholding Methods, for the current tables.  The IRS provides a tax withholding estimator to help you determine your withholding.

Social Security tax

The Social Security withholding tax rate is 6.2%. The 2025 wage limit on which Social Security tax is calculated is $176,100.

Medicare tax 

The Medicare withholding is 1.45% up to $200,000 and 2.35% for wages received in excess of $200,000.