Audio Compressor
Reduce the size of an audio file by re-encoding it to MP3 or AAC at a bitrate you choose, anywhere from 64 to 320 kbps. This is the honest way to make audio smaller: you decide exactly where the quality-versus-size line falls, rather than accepting whatever a service decides for you. It is free, needs no account, and adds no watermark to your result.
Audio Compressor
Add your files. Recommended settings are ready, so you can process in one click.
PDF, Word, images, audio, video, archives and more
Up to 100 files · 250 MB · No account- 1Add files
- 2Choose an action
- 3Download or keep going
What happens to your file.
FFmpeg re-encodes the audio to MP3 or AAC at the selected bitrate, so playback speed and pitch are unaffected, and the tags and cover art are carried over. Bitrate is the setting that actually determines file size: halving it roughly halves the file. A file that is already smaller than the chosen bitrate would make it, such as a voice note at 64 kbps, is compressed at about two thirds of its own bitrate instead, and you are told if it cannot be made any smaller, so the result is never bigger than what you started with.
Where it stops: Compression is lossy and cannot be reversed, so keep the original if you may need to edit it later. Below about 96 kbps music develops audible artefacts, though speech remains perfectly clear much lower down.
Which bitrate?
| Bitrate | Good for |
|---|---|
| 320 kbps | The highest MP3 quality; hard to tell from the source |
| 256 kbps | Very good; a common choice for music |
| 192 kbps | Good quality at a reasonable size |
| 128 kbps | Acceptable for music, fine for speech; the default |
| 96 kbps | Speech and podcasts; music starts to suffer |
| 64 kbps | Speech only, and noticeably so |
Getting the smallest file that still sounds right
- Variable bitrate (VBR) gives better quality than a fixed rate at the same size, and every modern player supports it.
- Mono halves the size and is fine for speech, but it collapses a stereo music mix.
- MP3 plays everywhere, M4A (AAC) suits Apple devices, and Opus is the smallest for speech.
- The expected size is shown before you compress, so you can adjust first.
What people use it for.
Everything you need, without a paywall.
Common questions.
What bitrate should I use?
For speech, 64 to 96 kbps is clear and very small. For music, stay at 192 kbps or above. Mono speech can go lower still without any practical loss.
Can I compress without losing any quality?
Not with MP3 or AAC, which work by discarding audio. If the file must stay identical, convert to FLAC instead, which is lossless but only reduces size by roughly a third.
Will the audio play at the wrong speed?
No. Speed and pitch are unchanged; only the file size changes.
Why would a compressed file come out bigger?
Because re-encoding a file that is already small at a higher bitrate adds data. Here that cannot happen: a voice note or a low-bitrate MP3 is compressed below its own bitrate instead, and if it is already as small as it sensibly gets, you are told rather than handed a larger file.
Are the tags and album art kept?
Yes. The title, artist and album tags and the cover picture are carried over to the MP3 or M4A.
You might also need.
Convert audio files between MP3, WAV, M4A, FLAC and OGG using FFmpeg with bitrate and quality controls.
Convert M4A audio to MP3 for broad compatibility across players and devices.
Normalize perceived loudness using FFmpeg loudnorm processing for more consistent playback volume.
Inspect codec, sample rate, channels, duration, bitrate, tags and stream metadata using ffprobe.