Make an audio file smaller with this free online audio compressor. Upload a track, pick a quality, and download a compressed MP3 — and see exactly how much smaller it gets. Everything runs in your browser, with nothing uploaded and no signup.
Audio Compressor
Make an audio file smaller. Upload a track, choose a quality, and download a compressed MP3 — see exactly how much smaller it gets. Everything runs in your browser; nothing is uploaded.
Audio files get smaller by lowering the bitrate — fewer kilobits per second means a smaller file, with a gradual trade-off in quality. 128 kbps is a good balance for music; 96 or 64 kbps (especially in mono) is great for voice, podcasts and email. The size shown is the real compressed size — preview it before you download. If your file is already a low-bitrate MP3, there may be little left to save. Everything is processed on your device; nothing is uploaded.
How to compress an audio file
- Upload your file. Drag an MP3, WAV, M4A, OGG or FLAC onto the box (up to ~50 MB). It’s processed on your device.
- Choose a quality. Lower bitrates make smaller files. The tool shows the real compressed size and how much you’ve saved.
- Preview to hear the quality at that setting.
- Download the compressed MP3.
How compression works
Audio files get smaller by lowering the bitrate — the number of kilobits used per second. Fewer bits means a smaller file, with a gradual trade-off in sound quality. A one-minute clip at 128 kbps is about 0.9 MB; the same clip at 64 kbps is about half that. There’s no way to shrink audio without either lowering the bitrate or shortening the clip, so this tool focuses on the bitrate — and shows you the exact result before you download.
Which bitrate should I use?
- 320 / 256 kbps — near-transparent quality; only a small size saving over the original for most music.
- 192 kbps — very good quality, noticeably smaller.
- 128 kbps — the classic balance for music: small files, good quality.
- 96 / 64 kbps — great for voice, podcasts, audiobooks and email, where small size matters more than hi-fi.
The mono option doesn’t shrink the file on its own, but it makes low bitrates sound clearer for speech — so pair it with 64–96 kbps for voice recordings.
What you can use it for
- Email & messaging — get a file under an attachment limit.
- Podcasts & voice notes — smaller episodes that stream and download faster.
- Websites & apps — lighter audio for faster pages.
- Storage — fit more music or recordings on a device.
Free, private, and fully in your browser
All decoding and encoding happen locally with the Web Audio API — your file never leaves your browser, there is no signup, and there is no watermark. Need to change format or sample rate instead, or trim the clip first? Try the Audio Converter and Audio Cutter.
Frequently asked questions
How do I make an audio file smaller?
Upload it here and choose a lower bitrate — the tool re-encodes it to a smaller MP3 and shows the size saved. Preview to check the quality, then download.
Will compressing reduce the quality?
Lower bitrates gradually reduce quality. 128 kbps is a good balance for music; 320 kbps is near-transparent; 64 kbps is fine for voice. Preview each setting and pick the smallest that still sounds good to you.
Does converting to mono make it smaller?
Not by itself — at the same bitrate, mono and stereo files are the same size. Mono does sound clearer at low bitrates, so it’s worth turning on when you compress voice to 64–96 kbps.
My file barely got smaller — why?
If your original is already a low-bitrate MP3, there’s little left to remove. Compression saves the most on high-bitrate MP3s and uncompressed WAV files.
Does it upload my file?
No. Everything runs in your browser using the Web Audio API; your file never leaves your device.
What does it export?
A compressed MP3 at the bitrate you choose.
Is it really free?
Completely — no signup, no watermark, no limits.