Independently adjust the speed and pitch of any audio file in your browser using real-time time-stretching. Slow a track down without changing its key, or transpose it to a new key without changing its tempo. Files stay on your device, nothing is uploaded.

How to use it

  1. Drag and drop an audio file onto the tool or click to browse (MP3, WAV, FLAC, OGG, and other common formats; max 150 MB, max 30 minutes).
  2. Use the speed slider to set a value between 0.25x and 3x (default is 1x, original speed).
  3. Use the pitch slider to shift between -12 and +12 semitones (default is 0, original pitch; ±12 semitones = one full octave).
  4. Click Preview to hear the result immediately, if you adjust the slider while audio is playing, it restarts at the new setting automatically.
  5. Once satisfied, choose WAV or MP3 and click download to save the full rendered file.

FAQ

Are speed and pitch truly independent, or does changing one affect the other? They are fully independent. The tool uses a time-stretching algorithm (SoundTouch) so you can slow audio down without lowering the pitch, or raise the pitch without speeding up the tempo.

How far can I push the settings before quality degrades? Speed changes between 0.7x and 1.5x tend to sound natural; below 0.5x you may notice a watery or phasey quality, and above 2x speech can become hard to understand. For pitch, the tool supports the full range of ±12 semitones (one octave), but shifts within ±4 semitones tend to sound the most transparent, larger shifts are fully usable but may introduce audible artifacts depending on the source material.

Does the real-time preview match the downloaded file exactly? It should for most files. For very long files or unusual formats, it is worth listening to the download from start to finish to confirm the result matches the preview.

What file size and duration limits apply? Maximum 150 MB and 30 minutes. Files larger or longer than that cannot be loaded.