Generate a metronome click track specification from BPM and bars

Provide the tempo in beats per minute, a time signature such as 4/4 or 6/8, and the desired duration in whole bars. The result lists every click from time zero, identifies its bar and beat, and marks the first beat of each bar as accented. Use the structured output to schedule sounds, drive animation, prepare practice tools, or test beat-aware software with repeatable timing data.

Describe the musical grid

Enter a positive BPM value, a time signature in numerator/denominator form, and a positive whole number of bars. BPM measures the beat unit named by the denominator, so 120 BPM in 4/4 means quarter-note beats arrive every half second, while 120 BPM in 6/8 means eighth-note beats arrive every half second. The numerator determines how many clicks belong to each bar. The generator starts the first click at timestamp zero because playback systems normally schedule the opening downbeat at the beginning of their timeline. It then advances by exactly sixty divided by BPM seconds for every later click. This definition avoids hidden count-ins, swing, subdivisions, or audio latency. If a session needs those features, it can transform or offset the returned schedule explicitly. Keeping the input small and musical also makes the result useful across browser audio, native audio engines, video timelines, test fixtures, and notation applications without tying it to a particular sample rate or sound file.

Read timestamps and accents

Each click record contains a one-based global index, a one-based bar number, a one-based beat number, a timestamp in seconds, and an accented flag. The first beat of every bar has accented set to true; all remaining beats are false. This gives a renderer enough information to choose a stronger click sample for downbeats while using a normal sample elsewhere. Timestamps are rounded to nine decimal places so JSON output stays stable while retaining sub-microsecond precision for ordinary musical tempos. The summary also reports the click interval, total duration, click count, beats per bar, and beat unit. Total duration describes the complete requested span through the end of the final beat interval, not merely the timestamp of the final click. For example, a one-bar 4/4 track at 120 BPM contains clicks at 0, 0.5, 1, and 1.5 seconds, while its complete duration is 2 seconds. That distinction helps prevent clipped final beats when allocating an audio or animation timeline.

Schedule the specification safely

Treat the result as a timing specification rather than rendered audio. A Web Audio application can add its playback start time to every timestamp and schedule an accent buffer or regular buffer according to the flag. A digital audio workstation script can convert seconds to its own timeline units, and a test suite can compare expected transport events without depending on speakers or media codecs. The function is deterministic: identical inputs always produce identical JSON, and it does not use the network, the current clock, or random values. Invalid tempos are rejected, including zero, negative values, missing values, infinities, and nonnumeric text. Signatures must contain a numerator from 1 through 32 and a conventional power-of-two denominator from 1 through 32. Bars must be a positive integer, and the completed schedule is limited to 10,000 clicks to keep responses practical. Because timestamps are relative to zero, application latency and device compensation remain the caller’s responsibility; add those offsets only when the final playback environment is known.