Cents between frequencies API

Computes the interval in cents, semitones and octaves between two frequencies using the canonical 1200·log2 ratio — the unit microtuning and intonation work depends on. Answers 'How many cents between 440 and 523.25 Hz?', 'Is this interval a true octave?'.

Price$0.02per request

MethodPOST

Route/v1/music/cents-between

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

musiccentsfrequencyintervalintonationmicrotuningratiosemitonesaudio

API URLhttps://x402.hexl.dev/v1/music/cents-between

Integration docs

Example request

{
  "f1": 440,
  "f2": 523.2511
}

Example response

{
  "f1": 440,
  "f2": 523.2511,
  "ratio": 1.18920705,
  "cents": 299.9999,
  "semitones": 2.999999,
  "octaves": 0.25,
  "direction": "f2 is higher",
  "formula": "cents = 1200 · log2(f2/f1)"
}

Input schema

{
  "type": "object",
  "required": [
    "f1",
    "f2"
  ],
  "properties": {
    "f1": {
      "type": "number",
      "examples": [
        440
      ]
    },
    "f2": {
      "type": "number",
      "examples": [
        523.2511
      ]
    }
  }
}

Output schema

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