Prediction of evacuee movement is an essential component in most performance-based designs. Safe egress is assumed to be achieved if the required safe egress time (RSET) is sufficiently shorter than the available safe egress time (ASET). The app is aimed at determining the RSET by applying the PD 7974:6-2019 standard principles. The RSET calculation considers a number of variable parts to arrive at an overall estimation of escape time: detection time, alarm time, pre-movement time, evacuation time to a place of relatively safety, and a margin of safety.