How to use the Audio Speed Changer
- Drop an audio file into the box, or click choose a file. Videos work too.
- Drag the Speed slider, or click a preset like 0.75× or 1.5×.
- Leave Keep the pitch ticked for natural voices. Untick it for the classic sped-up or slowed-down sound.
- Listen to the result, then click Download.
Keep the pitch, or not?
Playing a record faster also makes it higher, like a chipmunk. With Keep the pitch ticked, the audio is time-stretched instead: it gets faster or slower but voices and notes stay where they were. That's what you want for lectures, podcasts and practising music. Untick it for the "sped up" and "slowed" versions of songs popular on TikTok, where the pitch moves with the speed.
Popular speeds
- 0.5× to 0.75×: learning a fast guitar solo, dance routine or language lesson.
- 1.25× to 1.5×: lectures, audiobooks and voice notes, saving a quarter to a third of the time.
- 2×: skimming long recordings.
The tool also changes pitch by semitones, adjusts volume, and can reverse audio, all at once. MP3s are made with LAME, the open-source MP3 encoder.
Frequently asked questions
Does slowing down affect the quality?
Small changes sound natural. Very slow speeds with the pitch kept can sound slightly smeared, which is normal for time-stretching.
Can I speed up a WhatsApp voice note?
Yes. Save the voice note to your device, then open it here.
Can I change speed and pitch separately?
Yes. Set the speed, keep the pitch ticked, then use the Pitch slider.
Are my files uploaded?
No. Everything happens in your browser.