Reverb decay time from BPM calculator

Non-positive tempos or beat counts are rejected with invalid_input so automation never stores a negative or infinite decay.

How to call the API and what comes back

Tempo must stay strictly greater than zero and at most one thousand BPM; the beat count must stay strictly greater than zero and at most one million. The steps array walks from the raw tempo through the beat duration, the multiply by beat count, and the conversion to seconds so you can assert intermediate values in tests. Send a JSON body with two required finite numbers: bpm, also accepted under the aliases tempo, beats_per_minute, and tempo_bpm; and beats, also accepted as num_beats, beat_count, decay_beats, or tail_beats. Missing fields, non-numeric strings, non-finite values, and out-of-range numbers return invalid_input and are never charged. On success the response echoes the rounded bpm and beats, sets beat_ms and ms_per_beat to the quarter-note duration in milliseconds, sets decay_ms and reverb_decay_ms to the same tail length in milliseconds, sets decay_seconds to that length divided by one thousand, unit to the string ms, formula to the closed relation decay_ms equals sixty thousand over bpm times beats with one beat equal to a quarter note, and message to a short English summary. Pricing is a flat $0.002 per successful request with unit item.

Practical tips, limits, and related searches

Prefer sending numbers rather than pre-formatted strings when you control the client; string numbers are accepted only when they match a strict finite numeric pattern. Common studio checkpoints are easy to memorize: one hundred twenty BPM with four beats is two thousand milliseconds; one hundred twenty-eight BPM with two beats is nine hundred thirty-seven point five milliseconds; seventy-two BPM with one beat is eight hundred thirty-three point three recurring milliseconds. Prefer this capability when you already know the project tempo and only need the tail length in milliseconds; if you need every note-value and delay preset for the same tempo, use a dedicated BPM-to-milliseconds table instead. Keep BPM inside the published range so the reciprocal beat duration stays finite in IEEE double precision on the Worker and in the browser. When teaching, pair a positive happy path with a deliberate zero or negative tempo or beat count to demonstrate the hard invalid_input path. This landing targets people searching for a reverb decay time calculator from BPM, tempo-synced reverb ms, or beats-to-decay-time tool; it is not a geometric RT60 room calculator, not a full delay-note table, not a pre-delay or wet-dry mixer, and not a real-time audio processor. Failed tasks that return invalid_input do not consume prepaid balance, which keeps exploratory scripts cheap when learners deliberately probe edge cases. Round-trip checks are straightforward: recompute sixty thousand divided by bpm, multiply by beats, and confirm it equals decay_ms within twelve-decimal rounding.