NSW: 12 months from date of death.Section 36 of the Interpretation Act 1987 states that the date on any given day shall be calculated exclusive of that day i.e. Date of death 10 March 2012, due date 11 March 2013. In general, a month usually means a calendar month, where the first day is excluded. For example if a grant were issued on 15 July, the first day of a 6 month period would be 16 January. If the last day falls on a non business day, the relevant Act usually provides for an extension to the first business day following.