A device configured to monitor blood pressure includes an audio sensor, an optical sensor, and a processing device. The audio sensor is configured to generate an audio data signal representing a heartbeat of a subject over time. The optical sensor is configured to generate an optical data signal representing blood volume within a blood vessel of the subject over time. The processing device is configured to calculate a pulse wave transit time (PWTT) based on the audio data signal and the optical data signal. The processing device is also configured to calculate a blood pressure of the subject based on the PWTT.
