Free Online Audio Size Reducer
Shrink audio files by re-encoding — smaller MB, same song.
Drag & drop your audio file here
or
Max file size: 100 MB · MP3, WAV, FLAC, OGG
Original
beats per minute
musical key
Lower bitrates mean smaller files. 64 kbps is fine for voice; music wants 128 kbps or more.
Mono mixes both channels into one - ideal for voice recordings and podcasts.
Note: this is a file-size reducer - it re-encodes your audio at a lower bitrate so the file takes less space. It is not the same as the Compressor tool, which is a dynamics processor that evens out loud and quiet passages. Different name, different job.
Upload a file to see the estimated output size.
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Result
How it works
The Audio Size Reducer shrinks your audio files by re-encoding them: pick a lower MP3 bitrate (down to 64 kbps), optionally downmix to mono, and watch the result line tell you exactly how much smaller the file got - "Original: 8.4 MB → New: 1.1 MB (87% smaller)". It is built for sharing: email attachments, messaging apps and uploads with strict size caps.
A quick disambiguation, because the name invites it: this tool changes file size, not dynamics. The separate Compressor tool is a dynamics processor that evens out loud and quiet passages; this one re-encodes at fewer kilobits per second so the file takes less space. The live size estimate updates as you change the format or the mono checkbox, so you always know what you are getting before you download.
Everything runs client-side: decoding, the optional mono downmix and MP3/WAV encoding all happen in your browser tab, so your files never leave your device and nothing is uploaded anywhere.
Frequently asked questions
Is this the same as the Compressor tool?
No - and the similar name is confusing, so let's be explicit. The Compressor is a dynamics processor: it evens out loud and quiet parts of the sound. This Size Reducer is a file-size shrinker: it re-encodes your audio at a lower bitrate (and optionally mono) so the downloaded file takes less disk space. One changes how it sounds moment to moment; the other changes how many megabytes it is.
How much quality do I lose?
It depends on the bitrate you pick. 192 kbps MP3 is transparent for most listeners; 128 kbps is a good compact choice for music; 64 kbps is noticeably crunchy on music but perfectly fine for voice notes and podcasts. WAV 16-bit is lossless - it will not shrink the file at all, and is listed for completeness.
When should I use the mono option?
For anything voice-first: podcasts, interviews, voice memos, audiobooks. Mono roughly halves the file size again on top of the bitrate savings, and voices lose nothing meaningful in mono. Keep stereo for music.
Is there a file size limit? Is it private?
Files up to 100MB are supported. Re-encoding runs entirely in your browser - your audio never leaves your device.