A method for real-time determination of the service life of an electrochemical cell of a primary battery as a function of a determined application, the method comprising: - a step of measuring at least one value for current supplied by the electrochemical cell and at least one temperature value of the electrochemical cell in the determined application, - a total service life calculation step for calculating availability time of the electrochemical cell starting from a determined initial time, as a function of the at least one current value and the at least one temperature value measured during the measurement step, as a function of a determined value of capacity of the electrochemical cell, cut-off voltage ( Vc) for the determined application, and background current ( If) for the determined application characterized in that the total service life calculation step implements calculation of availability time of the electrochemical cell from the determined initial time using the formula C × Kp × R / (Imoy + Iad), wherein: - C corresponds to the determined value of capacity of the electrochemical cell, - Kp corresponds to a cutoff coefficient of the electrochemical cell and is a function, firstly of a maximum current value (Imax) drawn by the determined application and, secondly the cut-off voltage ( Vc) for the determined application, - Imoy corresponds to an average value of the current drawn by the determined application obtained from the one or more value(s) of the current supplied by the electrochemical cell, and including the value for background current ( If) for the determined application, - R corresponds to performance in terms of capacity of the electrochemical cell and is a function, firstly of the average value (Imoy) or the maximum value (Imax) of the current drawn by the determined application and, secondly temperature of the electrochemical cell in the determined application, - Iad corresponds to a value of the self-discharge current of the electrochemical cell and is a function, firstly of the average value of the current (Imoy) drawn by the determined application and, secondly temperature of the electrochemical cell in the determined application. - a step of measuring at least one value for current supplied by the electrochemical cell and at least one temperature value of the electrochemical cell in the determined application, - a total service life calculation step for calculating availability time of the electrochemical cell starting from a determined initial time, as a function of the at least one current value and the at least one temperature value measured during the measurement step, as a function of a determined value of capacity of the electrochemical cell, cut-off voltage ( Vc) for the determined application, and background current ( If) for the determined application - C corresponds to the determined value of capacity of the electrochemical cell, - Kp corresponds to a cutoff coefficient of the electrochemical cell and is a function, firstly of a maximum current value (Imax) drawn by the determined application and, secondly the cut-off voltage ( Vc) for the determined application, - Imoy corresponds to an average value of the current drawn by the determined application obtained from the one or more value(s) of the current supplied by the electrochemical cell, and including the value for background current ( If) for the determined application, - R corresponds to performance in terms of capacity of the electrochemical cell and is a function, firstly of the average value (Imoy) or the maximum value (Imax) of the current drawn by the determined application and, secondly temperature of the electrochemical cell in the determined application, - Iad corresponds to a value of the self-discharge current of the electrochemical cell and is a function, firstly of the average value of the current (Imoy) drawn by the determined application and, secondly temperature of the electrochemical cell in the determined application.