Loona Audio Speed Changer - Speed Up or Slow Down Audio Online Free
A lecture that drags, a podcast you want to finish sooner, a guitar riff you need to slow down to learn - this tool changes the tempo of any audio file. Move the slider, hear the result at the new speed right away, and download it as a WAV file.
How to change the speed of an audio file
- Click the box above or drag your audio file into it - MP3, WAV, M4A and OGG all work.
- Move the speed slider (or type an exact value) between 0.25x and 3x. The new duration updates as you drag.
- Press "Play at This Speed" to hear the result - voices will sound higher at faster speeds and lower at slower speeds.
- Click "Download WAV at This Speed" and the re-rendered audio saves to your device.
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Frequently Asked Questions
Is the Audio Speed Changer free?
Yes. It is completely free with no sign-up, no watermark and no limit imposed by us on how many files you process.
Are my audio files uploaded to a server?
No. Your file is decoded and re-rendered 100% inside your browser with the Web Audio API. It never leaves your device.
Does changing the speed change the pitch?
Yes - honestly, it does. This tool works like speeding up or slowing down a record: at 2x speed voices sound higher and smaller, at 0.5x they sound lower and deeper. If you need the tempo changed with the pitch kept the same, that requires a different technique (time-stretching) which this simple tool does not do.
Which formats can I use?
Any format your browser can decode - MP3, WAV, M4A and OGG in all modern browsers. The result downloads as a standard WAV file that plays everywhere.
How much can I change the speed?
From 0.25x (four times slower) to 3x (three times faster). A 4-minute song becomes 1 minute 20 seconds at 3x, or 16 minutes at 0.25x.
How it works
Your file is opened right inside your browser and decoded into raw sound samples with the Web Audio API - nothing is uploaded to any server. When you export, the samples are played back into an offline renderer at your chosen playback rate, which produces a shorter or longer recording, and that result is saved as a WAV file.
Worked example
You have a 60-minute recorded lecture and a one-hour commute. You load the file, set the speed to 1.5x, and the new duration shows 40 minutes. You preview a few seconds to check the voice is still easy to follow, then download the WAV - the whole lecture now fits into 40 minutes of listening.
Because speed and pitch are linked in this method, a 2x voice sounds noticeably higher. For lectures, podcasts and practice audio that is usually a fair trade; for music you may prefer smaller changes like 1.1x or 0.9x.
More questions
Why is the downloaded file bigger than my MP3?
The export is WAV, the uncompressed format your browser can create natively. WAV keeps the audio exactly as rendered, but the files are larger than MP3. Any standard converter can turn the WAV into MP3 afterwards if you need it smaller.
Can I speed up a very long lecture?
Yes, but very long files depend on your device memory, because the whole file is decoded and re-rendered in the browser. Most lectures, songs and voice notes work fine.
What speed is best for studying?
Many students use 1.25x-1.5x for lectures they have already heard once, and 0.75x for difficult passages or language learning. There is no rule - use whatever your ears follow comfortably.
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