Provisional tax is not a separate tax — it’s a method for paying income tax in advance on income that doesn’t have PAYE withheld. Anyone who earns more than the tax threshold from non-salary sources (sole proprietors, freelancers, landlords, investors with significant taxable interest, company directors of private companies) must register as a provisional taxpayer.
There are two compulsory payments. The first (IRP6) is due 31 August (six months into the tax year), based on at least 50% of the basic amount or estimated taxable income. The second is due by 28/29 February (year-end), and must cover at least 90% of the actual liability or 100% of the basic amount — whichever applies. Underestimating triggers a 20% penalty on the shortfall.
A voluntary third "top-up" payment can be made by 30 September (or 31 January for individuals with February year-ends) to avoid interest under section 89quat on any remaining balance. The annual ITR12 reconciles total provisional payments against actual tax owed.