Compress audio
Get a recording under a size limit without sending it anywhere.
- Runs on your device — the file is never sent anywhere
- No sign-up, no watermarks, no daily quotas
- Free, with no limit on how often you use it
How it works
Audio gets compressed for one of two reasons: an upload form has a limit, or a long recording has become unwieldy. Both are size problems, and uploading the oversized file to fix it is the slowest possible route.
What bitrate actually means
Bitrate is how much data each second of sound is allowed. 192 kbps is near-indistinguishable from a CD for most listeners. 128 kbps is the long-standing default and is transparent enough for casual listening. 64 kbps is noticeably worse for music but perfectly clear for speech, and halves the file again.
Mono halves it again
A stereo recording carries two channels. Interviews, voice memos, lectures and phone recordings almost never use the stereo image for anything, so mixing down to mono removes half the data with no practical loss. For music, keep stereo.
Already-compressed audio
If a file is already at or below the bitrate you pick, compressing it again makes it no smaller and only degrades it. The tool tells you when that happens rather than handing back a worse file without comment.
What you get back
An MP3, which is the safest format for compatibility. If you need a different format, use the audio converter afterwards.
Compress audio — questions
How much smaller will it get?
Roughly proportional to the bitrate change. Going from 320 to 128 kbps is about a 60% reduction; adding mono roughly halves it again.
Which bitrate should I choose?
128 kbps for music, 64 kbps for speech. Drop to 32 kbps only if a hard limit forces it.
Does it lose quality?
Yes — that is how compression works. The defaults are chosen so the loss is hard to notice.
Is my file uploaded?
No. Everything runs in your browser.