Compress MP3

Shrink an MP3 by re-encoding it at a lower bitrate — in your browser.

Select an audio file

Re-encode an MP3 at a lower bitrate to shrink it — pick the bitrate below. Runs in your browser.

点击选择，或将文件拖到此处

如何 Compress MP3

1
Add your MP3
Drop in the file you want smaller.
2
Pick a bitrate
128 kbps for voice, 192 for a good default — lower bitrate, smaller file.
3
Compress and download
Click Compress; it's re-encoded in your browser.

How much smaller will it be?+

It depends on the original bitrate. Going from 320 to 128 kbps roughly halves the file; the tool shows the before/after size.

Is quality lost?+

Yes — re-encoding an MP3 at a lower bitrate discards more detail. 192 kbps is a good balance; 128 is fine for speech.

Is my file uploaded?+

No. It's decoded and re-encoded in your browser with a JavaScript LAME port.

Can I set a target size?+

Not directly here — pick the bitrate. Lower bitrate, smaller file.

你们会把我的文件上传到服务器吗？+

不会——这里的每个工具都完全在你的设备上处理文件，不会向服务器上传任何内容。唯一的例外是 AI 工具，它们会把提取的文本（而非文件本身）发送给 Claude 来完成工作。

有文件大小限制吗？+

我们没有人为设置限制，但由于处理过程在你的浏览器中进行，非常大的文件（超过 500MB 或 1000 页）会受到你设备内存的限制，而非我们的限制。