The Government issues treasury bonds at a discount from par at either a zero or a fixed coupon rate for periods extending beyond one year. It makes fixed interest payments to the investor semi-annually. At maturity, the investor receives the face value amount.

This calculator works out the total interest return to an investor after deducting withholding tax at the standard 15% rate. The National Treasury from time to time issues tax-exempt infrastructure bonds and long term bonds at preferential taxation rates. The calculator allows for a change in the withholding tax rate.