This project aims to provide an algorithm to estimate respiratory rate from wearable photoplethysmogram (PPG) signals for use in daily life. The project consists of three parts. Firstly, updating our toolbox of respiratory rate algorithms to include the latest developments in technology. Secondly, using this toolbox to assess the performance of algorithms when used with wearable data in daily life. Thirdly, to create a recommended algorithm for use in wearables. It is our hope that this project will contribute to providing robust methods to monitor RR unobtrusively and at scale.