Systems and methods for determining a blood pressure of a subject from a photoplethysmogram are disclosed. The systems and methods include acquiring raw photoplethysmogram (PPG) data from a subject by measuring light reflected from or transmitted through a portion of the subjects body, determining a mean beat shape from the raw PPG data, and analyzing the mean beat shape to determine a blood pressure of the subject. The method can include analyzing a distinct shape of the mean beat shape to determine the blood pressure. The method can include identifying individual beats within the raw PPG data, collecting motion data and filtering the individual beats against the motion data, measuring biometric features of filtered beats, scaling individual beats in time and amplitude, and measuring additional shape features of scaled beats.