Posted in Web 5121, City of Detroit Withholding Tax Schedule 2024 Part 3 is used by nonresidents and part-year residents to compute wages earned in Detroit. Do not complete Part 3 if all of your work is performed in Detroit because all wages are subject to tax. https://www.michigan.gov/taxes/-/media/Project/Websites/taxes/Forms/City-IIT/TY2024/5121.pdf?rev=fb9d74286aa5404f845f0c85e0026d3e&hash=506EC2B491470ABB349C7AFEE6A45679