Compress Audio Online Free & Private
Reduce MP3, WAV, FLAC, and M4A file sizes by up to 90%. Choose your quality level, compress in your browser — no uploads, no servers.
Drop Audio (MP3, WAV, FLAC, M4A) files here or click to browse
Up to 150MB each — unlimited files
How to Compress Audio Online
Upload Audio Files
Drop MP3, WAV, FLAC, or M4A files. You can add multiple files and compress them all in one batch.
Choose Your Bitrate
64 kbps for voice, 128 kbps for standard music, 192–320 kbps for audiophile quality. Lower = smaller file.
Download Compressed MP3
Files convert in seconds in your browser. Download individually or all at once.
Bitrate Guide: Which Quality Should You Choose?
Ideal for speech, interviews, podcasts. Noticeably lower quality for music.
Decent for casual listening. Smaller than 128kbps while retaining most musical detail.
The most common bitrate. Excellent for everyday listening — most people can't tell it from the original.
Hard to distinguish from lossless in blind tests. Great for music you care about.
The highest standard MP3 quality. Near-indistinguishable from lossless source.
100% Private
Audio files often contain personal content — recordings, music, voice memos. Nothing is transmitted. Compression runs inside your browser tab.
No Upload Wait
A 100MB WAV file would take minutes to upload. Here it compresses in seconds without any network transfer.
No Limits
Compress your entire audio library in one session. No account required, no file count limits.
Frequently Asked Questions
How does audio compression work in the browser?
Your browser decodes the audio file using the Web Audio API, extracting raw PCM (uncompressed) audio data. It then re-encodes this to MP3 at your chosen bitrate using the open-source lamejs encoder. The result is a smaller file — no server involved.
What audio formats can I compress?
You can compress MP3, WAV, FLAC, M4A, AAC, and OGG files. The output is always MP3, which offers the best compression and universal compatibility. Browser support varies: WAV and MP3 work everywhere; FLAC works in Chrome/Firefox; M4A works in Chrome/Safari.
How much can audio be compressed?
It depends heavily on the source format. WAV files see the most dramatic reduction — up to 90% smaller as a 128kbps MP3. A MP3 at 320kbps compressed to 128kbps will be 60% smaller. A 64kbps MP3 compressed further will show minimal size reduction with significant quality loss.
What bitrate should I use for my audio?
64 kbps is fine for voice-only content like podcasts, audiobooks, and voice memos. 96–128 kbps is good for general music listening. 192 kbps is high quality, hard to distinguish from lossless. 320 kbps is maximum MP3 quality, near-indistinguishable from original.
Is this safe for private audio recordings?
Yes. All processing happens inside your browser tab using JavaScript. Your audio data never leaves your device — there are no network requests made during compression.
Will compressing an already-compressed MP3 further reduce quality?
Yes. Each time you encode audio with a lossy codec like MP3, you introduce a new round of compression artifacts. If you compress an already-low-bitrate MP3, quality can drop noticeably. For best results, compress from high-bitrate or lossless sources (WAV, FLAC, high-bitrate MP3).
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