Change Audio Speed
Adjust playback speed.
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Speed, pitch, and how to change one without the other
Play a recording faster by simply reading its samples more quickly and the pitch rises with it — the chipmunk effect, familiar from tape played at the wrong speed. That happens because speed and pitch are the same property when you are just replaying samples at a different rate.
Time stretching separates them. Algorithms such as the phase vocoder analyse the audio in overlapping windows, then reconstruct it over a longer or shorter duration while preserving the frequency content, so a lecture can play at 1.5× and still sound like the same voice. It is not free: aggressive stretching introduces artefacts, and transients like drum hits or consonants can smear. Speech tolerates far more stretching than music does, which is why 2× podcasts sound fine and 2× music does not.
Why we built this tool
The usual reasons are getting through lectures, podcasts, and recorded meetings faster, or slowing something down to transcribe it, learn a musical passage, or catch what was said in a difficult recording.
Those recordings are frequently confidential — internal meetings, interviews, medical or legal dictation. Uploading them to a speed-changing service means handing over the whole conversation. Ours processes the audio in your browser with the Web Audio API and a WebAssembly encoder, so the recording stays on your device from start to finish. No upload, no duration cap, and no account, which also means no limit on how many files you run through it.
Tips and common mistakes
- Enable pitch preservation, or voices turn comical as the speed rises.
- Speech tolerates far more stretching than music does.
- Increase gradually — 1.25× is comfortable for most listeners, and 2× takes practice.
- Slow down rather than speed up when transcribing a difficult recording.
Quick start: using Change Audio Speed
- Load the audio file you want to adjust.
- Set the speed multiplier — try 1.25× or 1.5× before going higher.
- Enable pitch preservation so voices stay natural.
- Preview a section to check for artefacts.
- Export the adjusted file and download it.
Cut out dead air as well with Remove Silence, or trim the file first using Cut Audio.