Reduce your audio file's size while keeping it clear enough for everyday listening. Works instantly in your browser — no upload, no account needed.
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Choose Audio FileMP3, WAV, OGG, M4A · Max 30MB
Good balance for music and general use.
Compressing your audio... this can take a moment for longer files.
This tool reduces an audio file's size by re-encoding it as MP3 at a lower bitrate, with a choice of compression levels. The result is a smaller file that's faster to upload, attach to emails, or store, while remaining clear enough for typical listening.
Compression happens entirely in your browser using the Web Audio API and a JavaScript MP3 encoder — your audio is never uploaded to a server.
For speech and podcasts, 64-96kbps often produces a significant size reduction while remaining perfectly clear, since speech doesn't require the same frequency range as music. For music, 128kbps is a reasonable balance of size and quality for casual listening, while 192kbps preserves more detail for closer listening. The right choice depends on how much the file needs to shrink versus how much quality matters for your use case — you can always try a setting, check the resulting size, and adjust if needed.
The size reduction depends on your original file's format and bitrate compared to your chosen output bitrate. A WAV file converted to 128kbps MP3 can shrink by roughly 80-90%, since WAV is uncompressed. An already-compressed MP3 re-encoded at a lower bitrate than its original will also shrink, though by a smaller percentage, and re-encoding an already-compressed file can introduce some additional quality loss compared to compressing directly from an uncompressed source.
Bitrate measures how much data is used to represent each second of audio — higher bitrates mean more data per second, which generally allows for more accurate reproduction of the original sound, at the cost of larger files. Below a certain bitrate, compression algorithms have to make increasingly aggressive simplifications to fit the audio into less data, which can result in audible artefacts — a slight "underwater" or muffled quality, loss of high-frequency detail, or distortion during complex passages. Where exactly this becomes noticeable depends on the content: spoken word, which occupies a relatively narrow frequency range, tolerates much lower bitrates before sounding compromised compared to music with wide dynamic range, multiple instruments, or high-frequency detail like cymbals.
Different destinations for your compressed audio have different practical constraints worth considering. For email attachments, checking your email provider's attachment size limit (commonly 25MB, though this varies) and compressing to comfortably fit within it — with some margin, since email services sometimes add overhead to attachments — avoids the frustration of a bounced email. For messaging apps, most have generous enough limits that moderate compression (128kbps) rarely causes issues, but very long voice recordings can still add up. For long-term archival of recordings where you might want to revisit the original quality later, it's worth considering keeping an uncompressed or lightly-compressed master copy separately, and only compressing copies intended for sharing or casual listening — since compression, especially at lower bitrates, isn't reversible to recover the original quality.
If you need to trim the file to a shorter section before or after compressing, use Audio Trimmer. For converting between formats without necessarily reducing size, see Audio Converter.
At the higher compression levels (64-96kbps), speech generally remains clear, while music may show some loss of detail. Higher bitrates like 128-192kbps preserve more quality for music while still reducing size.
The compressed file is output as MP3, which is widely compatible and significantly smaller than uncompressed formats.
Yes, though re-encoding at a lower bitrate than the original can introduce some additional quality loss compared to compressing from an uncompressed source.
Files up to 30MB are supported, with the practical limit also depending on your device's available memory.
No, compression happens entirely within your browser.