Earnings Periods: Change of earnings period with the same employer: Change to longer interval
Regulation 18, SS(C)R 2001
If an employees regular earnings period changes to a longer interval, eg weeklyto monthly paid, work out the NICs on payments made after the change using the newinterval. If an employer has made a payment at the old shorter interval in the first ofthe new longer periods take that payment and the NICs worked out on it into account whenworking out NICs for the new period as a whole. If the employee also becomescontracted-out when the earnings period changes, contracted-out rate NICs are due for thetotal payments made in the new earnings period.
A weekly paid employee changes to monthly paid, getting their last two weekly payments onthe 4th and 11th of the month. Their new earnings period is a tax month which alwaysstarts on the 6th of every month. All earnings paid in the same earnings period normallyhave to be added together. The employer should work out NICs on the first monthly paymenttaking into account the earnings and NICs on the payment made on the 11th, so that thetotal NICs payable are the same as if the two payments had been added together and monthlyNICs worked out. The weekly payment made on the 4th is not in the new earnings period andis not affected.