RaahUPSC · Audio Tools
Compress Audio
Reduce the size of an audio file by choosing a lower bitrate. Every input, whatever its format, is re-encoded to a constant-bitrate MP3, which plays almost everywhere.
✓ No upload · ✓ No sign-up · ✓ No watermark
How to use Compress Audio
- Add one or more files: MP3, WAV, M4A, AAC, OGG, FLAC, Opus or WMA.
- Pick a Bitrate: 192, 128, 96 (default), 64 or 32 kbps (voice).
- Click Convert; the output is always MP3.
- Compare the size shown on each download button with your original, then save the MP3s or the ZIP.
Choosing the right bitrate
File size depends almost entirely on bitrate × duration. At 96 kbps a minute of audio is about 0.7 MB; at 64 kbps about 0.5 MB; at 32 kbps roughly a quarter of a megabyte. The tool runs libmp3lame with -b:a at the bitrate you select, so the final size is predictable before you start.
128 kbps suits music, 64–96 kbps is fine for lectures and podcasts, and 32 kbps is meant only for speech, for example when an application portal or email limit forces a tiny file. Picking a bitrate higher than the source's will make the file bigger, not smaller.
Limitations
- Output is always MP3; the original format is not kept.
- Sample rate and channels are not reduced, so 32 kbps stereo music will sound noticeably poor.
- Each re-encode of an already lossy file costs some quality.
Frequently asked questions
Which bitrate should I choose for a voice recording?
64 kbps is usually clear; 32 kbps works for speech when size matters most.
Why did my file get bigger?
Your source was already encoded below the bitrate you picked. Choose a lower option.
Can I compress WAV directly?
Yes. WAV, FLAC, M4A and the other listed formats are all accepted and come out as MP3.
Does compression happen on a server?
No, your browser does the encoding with FFmpeg WebAssembly, so the file stays with you.