The Iowa Department of Revenue is issuing updated income tax withholding formulas and tables for 2024. The Department updates withholding formulas and tables when necessary to account for inflation and for changes in individual income tax liability resulting from changes in Iowa law.

New for 2024

The Iowa withholding formula and the IA W-4 have been revised to accommodate certain changes enacted by the Iowa legislature in 2023 under Senate File 565. Regarding withholding, SF 565 replaced "number of allowances" with "amount of allowances" to be in line with federal withholding.

Because of changes under SF 565 reflected on the 2024 IA W-4 form, employees should be encouraged to file an updated Iowa W-4 using the 2024 IA W-4 form. For employees who do not file an updated W-4 using the 2024 IA W-4 form, employers should use $40 as the total allowance amount and $0 as the additional withholding amount when calculating these employees’ Iowa withholding amounts.

Employers can view the Iowa 2024 withholding formulas and tables online.

The Department has updated the online Withholding Estimator to help individuals calculate their 2024 withholding amounts. As a reminder, employers must update withholding amounts starting January 1, 2024 but employees can also make changes to their Iowa W-4 (withholding) form by contacting their employer.

Employers with questions can contact the Department at 515-281-3114 or 800-367-3388.