Otolaryngologists are increasingly performing thyroid surgery and are responsible for optimising parathyroid function postoperatively. The aim of this study was to establish an evidence-based algorithm for the management of postoperative calcium levels and to try and answer some relevant postoperative management issues. These include the following: (1) What is the risk of hypocalcaemia both temporary and permanent? (2) When should calcium replacement be commenced and in what form? (3) What is the best method for calcium replacement without suppressing a recovering parathyroid? (4) How to identify recovering parathyroid function if the patient is already on calcium replacement? A systematic review of the literature was carried out supported by a retrospective analysis of postoperative calcium levels obtained from clinical records of patients undergoing thyroidectomy under our care (n = 167). We present an evidence based, user-friendly algorithm for the management of the serum calcium in patients undergoing thyroid surgery.