Compress audio
Re-encode at a lower bitrate for a smaller file.
This runs in your browser. Nothing is uploaded. Longer clips take longer here than they would on a fast server — that is the trade-off for not sending the file.
About Compress audio
Re-encodes audio at a lower MP3 bitrate in your browser so the file shrinks without being uploaded to a compressor.
A 32-bit float voice recording does not need to be 80 MB to send to a producer who asked for ‘the MP3.’ Pick 64, 96, 128, or 192 kbps. The page runs lame at that bitrate. 64 kbps speech is ugly and small. 192 kbps is what I would actually listen to. 96 is the default because this tool is named compress.
This is not a magic “same quality, 10% of the bytes” slider. You are throwing away information on purpose. If the source is already 96 kbps MP3, encoding again makes it worse, not smaller in a useful way. Convert from the WAV instead.
Same wasm core as everything else in Video and Audio. First visit still pays the 30 MB encoder tax, then it should stay cached.
If the result sounds crunchy, go up a bitrate or stop transcoding a file that was already a 64 kbps voice memo. Garbage in stays garbage, just smaller.
How to use Compress audio
- 1Drop the audio.
- 2Pick a bitrate.
- 3Click Compress, then Download and check the size.
What it won't do
- MP3 output only.
- No VBR picker, listed CBR values only.
Common questions
Which bitrate should I pick for speech?
96 kbps mono-ish speech is usually enough. Music wants 192 or a format that is not MP3. If you are unsure, start at 128 and look at the bytes.
Can I set a target file size in megabytes?
Not on the audio page. Bitrate times duration is the size. Do the arithmetic, or use the video compressor’s target field if you actually have a video.
Does this normalize loudness too?
No. Compress is bitrate. Normalize is loudnorm. Run them as two passes if you need both, normalize first if you care how the compressor hears the peaks.
Related tools
Why this one doesn't upload your file
There is no server to upload to. This page is a static file, and the work happens in your browser using the same graphics and WebAssembly code that renders every other site you visit. Your file is read from disk into memory, processed, and handed back as a download. Once the page has loaded you can disconnect from the network entirely and it keeps working. The longer explanation