I am trying to change for a employees weekly pay to have a flat rate paid to federal taxes and state taxes

@rwdaniel  It probably won't be truly flat due to the nature of medicare and social security rounding up and down by a penny every now and then, but what you want is as simple as paying a set salary, or paying a static amount of hours to the employee in question each week.

I appreciate your proactive approach to payroll management, @rwdaniel. I understand you're looking to configure QuickBooks Online (QBO) Payroll so that a specific employee has a flat rate deducted for both federal and state taxes each week. To some extent, it is achievable as FishingForAnswers has answered. Let's work together to get you set up with the right settings in QBO Payroll.

First, please know that withholding calculations must follow IRS and state guidelines, which base the amounts on the employee’s earnings, filing status, and details provided in their withholding forms.

For federal income tax, QBO Payroll calculates it automatically using the IRS's percentage method. This means that the tax is calculated based on the employee’s gross wages, filing status, and the information provided on their Form W-4. Moreover, federal withholding amounts can fluctuate during the year if there are any changes in the employee's wages, such as bonuses or other additional pay.

Moreover, QBO Payroll also automatically calculates state income tax based on state-specific guidelines and requirements which can vary. You can check out your state’s withholding website for details.

I'll include this article as well to learn more about how your payroll taxes are automatically calculated in QBO: Understand how your payroll taxes are calculated.

Next, while setting a flat rate to withhold from your employee's weekly paycheck isn't directly achievable, your goal can be managed as FishingForAnswers advised by paying a set salary or a fixed number of hours to your employee. You can follow these steps to review your employee's pay:

1. Go to Payroll in your QBO account. Then, Employees.
2. Select the employee profile with the weekly pay.
3. Scroll down to the Pay types section, and click on Edit.
4. Click on the Get more info on pay types link to learn more about the pay types and deductions and how they impact federal taxes and forms.
   
   
5. Review the employee's pay types. Then, hit Save when done.

For future reference, I'm adding this helpful guide if you need a reference before closing your books and preparing for a new one in QBO: Year-end guide for QuickBooks Online.

Complying with IRS and State regulations is essential, and while we can't set a flat rate for tax withholdings, I hope these details help you get a closer option to your goal. If you need further assistance or have additional questions, feel free to click on the Reply button. We're committed to offering ongoing support. Take care!