Change audio speed from 0.5× to 2×: slow down a lesson to follow along, or speed up a podcast or voice note to save time. Voices keep sounding natural because the pitch stays the same. It works with MP3, WAV, M4A and more. It’s free, there’s no sign-up, and your file never leaves your device.
How to change audio speed
- Tap Choose file and pick your audio file.
- Choose a speed: 0.5×, 0.75×, 1.25×, 1.5×, 1.75× or 2×. The new length is shown straight away.
- Keep Keep voices sounding natural switched on for normal-sounding speech.
- Press Change speed, listen, then download.
When to slow down or speed up audio
- Learning. Slow down language lessons, lectures or dictation to catch every word.
- Music practice. Slow a song down to learn a tricky part on your instrument.
- Podcasts and audiobooks. Speed them up to listen in less time.
- Voice notes and meetings. Get through long recordings faster.
- Videos and content. Fit narration or music to a set length.
Keep voices natural, or go for the chipmunk effect
Normally, playing audio faster makes voices sound high and squeaky, and slower makes them deep. With Keep voices sounding natural switched on, this tool changes the speed while keeping the pitch the same, so people still sound like themselves. Switch it off if you want the classic sped-up or slowed-down effect.
How it works
Changing speed without changing pitch is called time stretching. This tool uses FFmpeg, the free, open-source engine behind many professional audio apps, to stretch or squeeze your audio in your browser. Your file is processed on your own device and never uploaded.
Tips for changing speed
- Small changes sound best. 1.25× and 0.75× are hard to notice as speed changes, while still saving time or making speech easier to follow.
- For podcasts, try 1.5×. Most people can follow speech comfortably at one and a half times normal speed once they get used to it.
- For learning, try 0.75×. It gives you time to catch each word without making voices sound unnaturally slow.
- Combine with other tools. After changing the speed, tap Keep editing this file to cut it, change the volume, or save it in another format.
- Turn off pitch keeping for effects. Switch off Keep voices sounding natural for the classic chipmunk voice at 2× or a deep, slow voice at 0.5×.
The new file is a normal audio file that plays at the new speed in any app or device, so you don’t need a special player that supports playback speed controls.
You can change audio speed for any common format, including MP3, WAV, M4A, FLAC, OGG and the sound from MP4 videos. Save the result in the same format, or pick a different one under Save as. Because everything runs on your own device, even long recordings stay private, and there is no waiting in an upload queue before the speed change starts.
More free audio tools
- MP3 Cutter: Cut MP3s and make ringtones
- Audio Trimmer: Trim WAV, M4A and other recordings
- MP3 Converter: Turn WAV, M4A or FLAC files into MP3
- Audio Converter: Convert between MP3, WAV, M4A, FLAC, OGG and OPUS
- MP4 to MP3 Converter: Get the sound from an MP4 video
- Video to MP3 Converter: Extract audio from MOV, WebM and MKV videos
Change audio speed FAQ
Which speeds can I choose?
0.5×, 0.75×, 1×, 1.25×, 1.5×, 1.75× and 2×.
Will voices sound strange?
Not with Keep voices sounding natural switched on. Speech stays at its normal pitch. Very large changes, like 0.5× or 2×, can sound slightly less smooth, which is normal for any speed changer.
How long will the new file be?
The new length is shown before you start. For example, a 30-minute recording becomes 20 minutes at 1.5× and 60 minutes at 0.5×.
Is it free?
Yes. No account, no watermark and no limit on use.
Are my files uploaded?
No. Speed changes happen in your browser on your own device. Nothing is uploaded or stored.
To keep only part of a recording, use the audio trimmer first. To make a sped-up file louder, try the volume tool.
You must be logged in to post a comment.