Change audio speed
Listen to a lecture at 1.5×, slow down a fast-talking passage, bring a song down to practice tempo. With preserve pitch on, voices don't turn squeaky or deep.
Free · no sign-up · your file is processed in your browser and never sent to a server
No file handy? Try it with a 20-second Turkish meeting recording.
Other pages for this tool
How to use
- Choose your fileDrop an MP3, WAV, M4A, OGG or FLAC file.
- Set the speedDrag the slider or use the arrow keys in 0.05 steps. The new duration appears right below; listen to the first 10 seconds to try it.
- Apply and downloadPress "Apply", listen to the result and download it in the format you choose.
One tool, three controls
| Control | What changes | What stays the same |
|---|---|---|
| Speed (preserve pitch on) | Duration | How high or low the voice sounds |
| Speed (preserve pitch off) | Duration and pitch together, like tape | — |
| Pitch | How high or low the voice sounds (semitones) | Duration |
| Volume | Loudness (dB); a limiter prevents clipping | Duration and pitch |
Which speed for what?
- 1.25–1.5×: Lectures, podcasts and audiobooks; most listeners follow comfortably at this speed.
- 0.75–0.9×: Language learning, dictation, taking notes on a fast passage.
- 0.5×: Instrument practice; hearing a passage note by note.
- 2× and above: Skimming a long recording to find a section.
How is the pitch preserved?
The tool splits the audio into short, overlapping pieces and re-arranges them at the points where the waveforms match best (the WSOLA method). The duration changes while the pitch stays the same. At extreme speeds (below 0.5× or above 2.5×) you may hear a slight echo or warble; that's the natural limit of the method.
Privacy: your file never leaves your device
Everything happens in your browser. Your file is not sent to Voiser's servers or stored anywhere, and it's cleared from memory when you close the tab. That's also why the tool stays fast on a slow connection.
Common questions
Does speeding up make the voice squeaky?
Not with "Preserve pitch" on; the voice keeps its tone. Turn it off and the pitch rises too, like a sped-up tape.
What speed range is supported?
From 0.25× to 4× in 0.05 steps. The most natural results are between 0.75× and 1.5×.
How is the new duration calculated?
New duration = old duration ÷ speed. For example, a 30-minute lecture at 1.5× becomes 20 minutes.
Does it change the speed of a video?
No, this tool works with audio only. You can get a video's audio first with extract audio from video.
Related tools
- Pitch changerRaise or lower the pitch of audio in semitone steps.
- Volume boosterMake quiet recordings louder, or normalize them, without clipping.
- Silence removerAutomatically find and remove long silences in a recording.
- MP3 cutter and audio trimmerSelect any part of an audio file on the waveform and cut it out.
- Voice changerApply effects like robot, echo, telephone and radio to a recording.
Voice your script at exactly the pace you want.
In the Text to Speech studio, speed, pitch and emphasis can be set for each sentence. Start with a free account.