Special DSP software was developed to automatically count sperm whale clicks recorded along acoustic transects, and to facilitate the calibration of these counts through automated and interactive analyses of dive cycle and range experiments. Minimum pulse width and maximum interpulse interval are used as criteria for automated click detection. In addition to these criteria, interclick intervals and click amplitudes can be used for the tracing of clicks during interactive analyses. Interactive analysis of a dive of a single whale recorded under almost ideal conditions gave the following results: The mean of all interclick intervals measured within bouts of regular clicks was 0.801 s (n=2203 intervals, cv 27.5%), the reciprocal of which corresponds to c. 1.25 clicks per second. Including 10 s between fluke-up and the first click recorded, silences between bouts of regular clicks, and a silence between the last regular click detected and two surface clicks found 3:37 min after the last regular click, the average click rate over a dive time of 42:23 min is 0.88 per second (n=2244 clicks). In several dive cycles analyzed, interclick intervals were found to oscillate periodically during bouts of regular clicks. These oscillations correlated with click amplitude.