Let’s start with why provisional tax exists. It is simply a way to spread the tax amount due by the person or company over a period of time. This is to ensure that a large amount of tax is not due when the relevant assessment has been completed. Basically it is similar to Pay As You Earn (PAYE), except it is less frequent. Where PAYE is due monthly, provisional tax is due every 6 months. Straight to the point, SARS wants to ensure that they get their money while it is most likely that you still have cash.
To answer the question of who should register for provisional tax, it is any person that derives any income other than a salary. In other words any income on which PAYE is not paid. Thus if you earn a salary and for example earn rental income you should register. From the SARS website:
“Any person who receives income (or to whom income accrues) other than a salary, is a provisional taxpayer. A provisional taxpayer is defined in paragraph 1 of the Fourth Schedule of the Income Tax Act, No.58 of 1962, as any –