NI Category C Change

NI Category C

The Historical NI changes wizard can not be used where the new NI category is category C.

This is because a negative employee’s NI is generated in the current period against category C, and this cannot be returned as part of the FPS

Could you carry out the process below until the wizard has been updated.


  1. Leave the employee on the ‘old’ NI category
  2. Calculate the changes required to the employee’s and employers NI.
  3. This link will take you to the HMRC NI calculator
  4. Enter the changes into the ‘Calculation Override’ screen (HR Record > Payroll Functions menu)
  5. The employee’s NI this month will then make those changes to the ‘old’ category.
  6. After period end change the NI category to the new value