Compress & Convert audio.
Shrink or convert audio locally — MP3, FLAC, OGG and more.
Drop audio files here
or browse your files
Paste with ⌘V · or drop files anywhere on the page
Files never leave your device. Everything runs in your browser, nothing touches a server — tools you've used even work offline.
Compress audio files or convert them between MP3, M4A, WAV, FLAC, OGG, OPUS and WEBA — everything encodes in your browser, and nothing is uploaded. Drop any audio file, or a video to have its audio track extracted, then pick a format and a bitrate or a target size. Free, with no ads and no length limits.
Before / after
Original — 4.7 MB
Compressed — 2.4 MB
Original
4.7 MB
Compressed
2.4 MB
Saved
−50%
Real result, not a mock-up: this 2:27 track went through the Compress Audio tool — LAME, the canonical MP3 encoder, at 128 kbps — and dropped from 4.7 MB to 2.4 MB. Both players hold the actual files, byte for byte. Press play and try to hear the difference — on most speakers you can't, and that's the point.
Music by The Mountain on Pixabay.
How it works
- Drop files anywhere on the page, click to browse, or paste with ⌘V.
- Pick a quality or preset — or set an exact target size and let the tool find it.
- Compress, compare before/after, and download — individually or as a ZIP.
Bitrate guide
Audio bitrate is a straight rate — kilobits per second times duration is the file size, no surprises. 192 kbps MP3 sounds identical to the original for most music on most gear; voice tolerates far less. When in doubt, convert once at 192 and compare it against the source with your own ears.
| Use | Bitrate |
|---|---|
| Voice memos & podcasts | 96 kbps |
| Music, casual listening | 192 kbps |
| Music, near-archival | 256–320 kbps |
MP3, M4A, OGG, FLAC or WAV?
MP3 plays absolutely everywhere and is the safe default. M4A (AAC) sounds slightly better at the same bitrate and suits Apple ecosystems. OGG squeezes best at low bitrates but some players still shrug at it — OPUS and WEBA write the same modern Opus audio under the names voice apps and web players expect. WAV is uncompressed — a format for editing, not sharing, at roughly 10 MB per minute of stereo; FLAC packs the same samples losslessly into about half that. Starting from a video instead? MP4 to MP3 pulls the audio track out directly.
Target size from duration
Because audio bitrate is constant, target-size mode can be exact: it divides your cap by the duration and picks the bitrate that fits, between 32 and 320 kbps. A 40-minute recording into 25 MB works out around 80 kbps — fine for speech, rough for music — and the math tells you honestly what’s possible.
Under the hood
Each format gets the encoder desktop audio tools actually ship: LAME for MP3, FFmpeg’s AAC encoder for M4A, libFLAC for FLAC — all compiled to WebAssembly — while Opus uses WebCodecs, the encoder already built into your browser. The pipeline is orchestrated by mediabunny, so whether you convert a recording or pull a track out of a video, everything encodes on your device.
Frequently asked questions
Which bitrate should I pick?
192 kbps MP3 sounds identical to the original for most music; 128 is fine for casual listening; 96 and below suit voice recordings and podcasts. M4A and OGG sound better than MP3 at the same bitrate, so they can go lower.
Can I turn a video into an MP3?
Yes — drop an MP4 or MOV straight onto this tab. The audio track is extracted and re-encoded to the format you picked; the video track is discarded.
Why is WAV so large?
WAV stores raw uncompressed samples — roughly 10 MB per stereo minute. Use it when a tool insists on WAV input or for editing; FLAC keeps it lossless at about half the size, and MP3/M4A/OGG sound identical at a tenth of it.
Is it private?
Yes. The audio is decoded and re-encoded entirely in your browser — recordings never leave your device, and the server does nothing but deliver this page. Voice memos, interviews, demos: none of it is uploaded anywhere. Want proof? Run one file through, switch your connection off, and run another — it still works.