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Local processing has no fixed file-size limit and depends on browser memory. Server limits: video 100 MB, other files 10 MB · Up to 5 files per batch
No registration · Free to useWhen to use this tool
Use MP3 compression to prepare an audio attachment for a size-limited message. Compression re-encodes the recording, so compare listening quality and the actual byte size before replacing your original.
Example: when to use this tool
An MP3 recording exceeds an attachment limit. Compress a copy and listen to a representative section. An already low-bitrate MP3 may not get smaller without reducing useful sound quality.
Quality and output
MP3 compression uses lossy re-encoding with the selected compression setting. It cannot improve the source and may add encoding artifacts. Listen to representative sections of the output.
How to use
- Upload a valid MP3 file.
- Choose a compression setting and start processing.
- Download the result and check it before replacing your original.
Before you download
Keep the source recording and avoid recompressing several generations. Smaller output is not guaranteed when the original MP3 already uses a low bitrate.