HMRC internal manual

National Insurance Manual

NIM08300 - Earnings Periods: Employee starts work

Regulation 3(1) Social Security (Contributions) Regulations 2001

Under Regulation 3(1) of the Social Security (Contributions) Regulations 2001, when an employee starts work, their expected earnings period comes into force from the start date.

The earnings period is determined by the regular interval between which the payment of earnings will be made. For example, an employee who will be regularly paid on a weekly basis will have a weekly earnings period. The more common pay periods for employees are–

  • Weekly;
  • Monthly;
  • Two weekly;
  • Four weekly


If an employee starts work on 10 August and is due to be paid monthly on the last day of the month, the earnings period will be monthly. A monthly earnings period will also apply to the first payment, although the earnings will only cover the period 10th August to 31st August If the employee leaves the job before the end of the first earnings period, eg 20 August, NICs on the first and only earnings payment are still calculated on a monthly basis.