You want to get through a two-hour lecture before lunch, or you are trying to learn a guitar solo that flies past too fast to follow. Both come down to the same thing: changing how fast the audio plays without ruining it. The speed changer does it in your browser, and it can hold the pitch steady so faster does not mean squeaky.
The short version: load the file, drag the speed slider, and export. Here is how to get it right.
How do I speed up or slow down audio?
Add your file, then move the speed slider. Past 1x the track plays faster and the file gets shorter; below 1x it plays slower and runs longer. Presets like 0.75x and 1.5x are one tap away for the common cases.
- Add a file. Drop in an MP3, WAV, OGG or M4A to see its waveform.
- Set the speed. Drag the slider or pick a preset, and decide whether to keep the pitch.
- Export. Preview the change, then save it as MP3 or WAV.
Should I keep the pitch?
This is the one choice that matters, and it depends on what you are doing.
- Keep pitch on. Voices and music stay at their normal tone while only the speed changes. This is what you want for lectures, audiobooks and podcasts at 1.25x or 1.5x, and for slowing music down to learn a part without it dropping into a different key.
- Keep pitch off. Faster also sounds higher, slower sounds lower, like an old tape machine. This is the right call when you actually want that effect for a sound design or comedy clip.
For almost all “I just want to listen faster” or “let me hear that riff slower” jobs, leave keep-pitch on.
Good speeds to start from
- Lectures and audiobooks: 1.25x is comfortable for most people; 1.5x once your ear adjusts. Past 2x, words start to blur.
- Learning music: 0.75x keeps the feel while giving you time to follow; 0.5x for a tricky run you want to nail note by note.
- Tightening a recording: small nudges like 1.1x can shave time off a podcast without anyone noticing.
A note on quality
Changing speed does not add noise or artefacts on its own. The only quality question is the export format. WAV stays lossless, which is the choice if the clip is heading into more editing. MP3 re-encodes at a high bitrate, with a change that is minimal and usually inaudible, and gives a smaller file that is fine for listening and sharing.
Why it stays on your device
The whole thing runs on your own machine. Your file is read locally, sped up or slowed down in the browser, and saved back to your computer, with nothing uploaded. That keeps private recordings private and removes any upload-size limit, so a long lecture processes the same as a short clip, with no watermark and no paywall.
When the speed feels right, open the speed changer and export. If you also want to nudge the key rather than the tempo, the pitch shifter moves the pitch while leaving the timing alone.