BPM to note durations API

Converts a tempo in BPM to the millisecond duration of every note value (whole through thirty-second), each with straight, dotted (×1.5) and triplet (×2/3) variants — the producer's tempo-to-time table. Answers 'How long is an eighth note at 120 BPM?', 'Dotted quarter ms at 90 BPM?'.

Price$0.04per request

MethodPOST

Route/v1/music/bpm-note-duration

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

musicbpmtemponote-durationmillisecondsdawproductiontimingaudio

API URLhttps://x402.hexl.dev/v1/music/bpm-note-duration

Integration docs

Example request

{
  "bpm": 120
}

Example response

{
  "bpm": 120,
  "quarterNoteMs": 500,
  "quarterNoteHz": 2,
  "durations": {
    "whole": {
      "straightMs": 2000,
      "dottedMs": 3000,
      "tripletMs": 1333.3333
    },
    "half": {
      "straightMs": 1000,
      "dottedMs": 1500,
      "tripletMs": 666.6667
    },
    "quarter": {
      "straightMs": 500,
      "dottedMs": 750,
      "tripletMs": 333.3333
    },
    "eighth": {
      "straightMs": 250,
      "dottedMs": 375,
      "tripletMs": 166.6667
    },
    "sixteenth": {
      "straightMs": 125,
      "dottedMs": 187.5,
      "tripletMs": 83.3333
    },
    "thirty-second": {
      "straightMs": 62.5,
      "dottedMs": 93.75,
      "tripletMs": 41.6667
    }
  },
  "note": "straight = note value, dotted = ×1.5, triplet = ×2/3"
}

Input schema

{
  "type": "object",
  "required": [
    "bpm"
  ],
  "properties": {
    "bpm": {
      "type": "number",
      "examples": [
        120,
        90
      ]
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}