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HMRC internal manual

National Insurance Manual

Class 2 National Insurance contributions: general information: contribution week

Regulations 1(2) and 155 of the Social Security (Contributions) Regulations 2001 (SI 2001 No 1004)

A self-employed earner is only liable to pay Class 2 NICs if the earner’s relevant profits are of or above the small profits threshold. In such circumstances, Class 2 NICs are due for the relevant tax year at the weekly flat rate in respect of each contribution week or part of a week that a person is self-employed.

A ‘contribution week’ is defined as a period of 7 days beginning with midnight between Saturday and Sunday. The first day of the contribution week is Sunday and Saturday is the last. The first week of the contribution year starts on the first Sunday after 5 April. Some contribution years will include 53 contribution weeks.


The first contribution week of the 2016 to 2017 tax year starts on Sunday, 10 April 2016 and the last contribution week of that year ends on Saturday, 8 April 2017.