a method for correctly measuring the time remaining for a tape running in a tape recorder on the basis of a previously calculated remaining time even when the speed of the tape running in the tape recorder changes or runs at a high speed . the method determines whether or not a present remaining time has been calculated and based on this determination other steps are performed . other steps include determining the rotation period of a supply reel , determining whether or not the tape is running at a normal speed or whether or not the tape is running in a forward direction , whether the speed of the tape is a high speed or not , subtracting from or adding to the rotation period , a change in rotation period based on the speed and direction of the tape for every rotation of the reel to calculate a new rotation period and calculating a new remaining time by subtracting the new rotation period from or adding the new rotation period to the present remaining time determined in the first mentioned step .