Change Audio Speed
Choose an audio file and a speed from half to triple, then download the faster or slower version as MP3 or WAV.
- Runs in your browser
- Free to use
About this tool
Change Audio Speed re-renders an audio file at 0.5× to 3× speed in your browser: slow a passage down to transcribe or learn it, or speed up a lecture to get through it faster. The result is encoded as MP3 or WAV with a player to check it.
Related: Audio Cutter, Audio Loop.
How to use it — quick steps
- 01
Add the audio file
Drop a WAV, MP3 or M4A file on the dashed area or choose it; a new file replaces the previous one.
- 02
Pick the speed
From 0.5× (half speed) to 3×; 1.25× and 1.5× are the usual choices for lectures and podcasts.
- 03
Press "Change speed"
The file is re-rendered at the new rate in your browser; play it and download it as MP3 or WAV.
Key features of this tool
Six speeds
Half speed for transcription practice up to triple speed for skimming; the duration changes accordingly.
MP3 or WAV output
MP3 at 128-320 kbps (encoded with LAME in the browser) or lossless WAV.
Processed on your device
Decoding, processing and encoding run in your browser with the Web Audio API; audio files are never uploaded.
Frequently asked questions
Does the pitch change?
Yes: like a tape, faster playback raises the pitch and slower lowers it. Pitch-preserving time stretching is on the roadmap.
How long does the result last?
Duration divided by the speed: a 60-minute lecture at 1.5× becomes 40 minutes.
Are my files or data uploaded?
No. The tool is plain JavaScript that runs in your browser; the files or data you provide here are never uploaded to our servers.