A device (110), method and system (100) for calculating, estimating, or monitoring the blood pressure of a subject are disclosed. A first signal representing heart activity of a subject may be received. A plurality of second signals representing time-varying information on at least one pulse wave of the subject may be received from a plurality of body locations of the subject. A first feature of the first signal may be identified. For each of the plurality of second signals, a second feature may be identified. A pulse transit time based on a difference of the first feature and at least one of the second features may be computed. A blood pressure of the subject may be calculated according to a model based on the computed pulse transit time. The model may include a compensation term relating to the plurality of second signals or the second features thereof.
