A method of calculating a blood pressure associated with one or more persons is provided. The method includes the following steps: (a) receiving, data points associated with at least one of a person from a database (b) calculating, global constant values for (i) one or more systolic blood pressures, (ii) one or more diastolic blood pressures, (iii) one or more pulse transit times, (iv) one or more heart rates using curve fitting techniques or regression techniques (c) obtaining, (i) reference systolic blood pressures, and (ii) reference diastolic blood pressures from the database (d) calculating, (i) a systolic offset constant, and (ii) a diastolic offset constant and (f) calculating, (i) a systolic blood pressure of the person based on the global constant values and the systolic offset constant value, and (ii) a diastolic blood pressure of the person based on the global constant values and the diastolic offset constant value.
