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01Audio & Voice toolAudio or transcript
Audio Compressor
Shrink audio files by re-encoding to a lower bitrate.
100% FreeRuns instantlyNo watermark
- 1Choose toolOpen the Vootkit workspace.
- 2Add inputProvide the content or settings.
- 3ProcessLet the browser do the work.
Private by designProcessed on your device where possible.
Works on any deviceDesktop, tablet and mobile browsers.
No installationOpen the page and start working.
Always free coreUse the free plan for everyday tasks.
How to use Audio Compressor
Provide the content or settings.
02Let the browser do the work.
03Copy, download or continue.
04Your files stay private
Your work is processed locally in your browser where possible and is never added to a Vootkit upload library.
Learn more about privacyA one-hour recording at full quality is far too large to email and far larger than speech needs. Speech in particular compresses extremely well, because most of what a high bitrate preserves is detail the human voice never produced.
What Audio Compressor does
Re-encodes audio at a lower bitrate to reduce file size, producing MP3 output.
How much you can cut depends entirely on the content. Speech survives aggressive compression; music does not.
Rough guidance
| Speech, mono | 64 kbps is usually plenty |
|---|---|
| Speech, stereo | 96 kbps |
| Music, acceptable | 128 kbps |
| Music, good | 192 kbps and above |
| Rough size | 1 MB per minute at 128 kbps |
| <strong>Already compressed?</strong> | <strong>Re-encoding loses quality again</strong> |
| Output | MP3 |
| Runs | In your browser — never uploaded |
Detailed steps
- Add the file.
- Choose a bitrate appropriate to the content, not to the file size you want.
- Listen to the result before deleting the original.
Worth knowing
Speech and music need completely different bitrates, and treating them the same wastes space or ruins the audio. A podcast at 64 kbps mono sounds fine and is a quarter the size of the same recording at 256; music at 64 kbps sounds obviously damaged. Identify what you have before choosing a number.
Frequently Asked Questions
What bitrate should I use?
64 kbps mono for speech, 128 for acceptable music, 192 or above for music you care about. The gap is large because speech occupies a narrow frequency range and music does not.
Can I compress an already-compressed file?
You can, and it loses quality again — lossy encoding is not idempotent. If you have the original, compress that instead of the compressed copy.
Why does my music sound hollow?
The bitrate is too low, or it has been through more than one lossy encode. The characteristic swirly, underwater quality on cymbals is the signature of an over-compressed or re-encoded file.
Is my audio uploaded?
No — it is processed in your browser. That matters for the recordings people most often need to shrink: interviews, lecture captures, therapy or medical notes, and voice memos that were never meant to leave the device they were recorded on.
Is Audio Compressor free?
Yes. The Vootkit free plan includes 5 tool runs a day. Upgrade to Vootkit Pro for unlimited daily use, an ad-free workspace and saved workflows.
Are my files uploaded?
No. Audio Compressor runs entirely in your browser — your file is processed on your own device and never sent to a server. There is nothing for us to store or delete.
Do I need to install anything?
No. Audio Compressor works in any modern browser on desktop, tablet or phone. Open the page and start.
How often can I use it? Is there a daily limit?
On the free plan you get 5 tool runs a day. When you reach the limit you'll see a prompt to upgrade, and it resets the next day. Vootkit Pro removes the cap entirely for unlimited daily use.
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This tool processes everything locally in your browser. You can disconnect from the internet after the page loads and it will still work.