Using tables, lists, and dropdowns and not sure how to make this work…

One approach I’ve found useful with setups like this is to keep the employee information and calculation rates in structured tables, then use the employee ID/name as the lookup key. The dropdown should mainly be used to select the employee, while formulas such as XLOOKUP can retrieve the corresponding rate and other fields automatically.

For example, the calculation could be structured conceptually as:

Wages × Employee Rate = FICA Withheld

That keeps the data-entry sheet much cleaner and reduces the chance of users accidentally entering or changing the wrong percentage.

I also work on web-based calculation tools at CalcPave, where the same principle of keeping inputs simple and letting the calculation happen automatically is useful: https://calcpave.com/

For this particular Excel workbook, though, I’d keep the employee data, rates, and lookup formulas inside Excel rather than adding unnecessary manual dropdowns for every calculated field.