Compress Audio Online — Free, No Upload
Shrink a music track or a voice recording to a fraction of its size.
Drop a file here
or click to choose a file
Runs on your device Your file is processed by your own browser and is never uploaded to a server.
Short answer
An audio file can be compressed for free in a web browser without uploading it. The file is re-encoded to MP3 at a lower bitrate, which typically reduces a 320 kbps track by 60% at 128 kbps and a WAV recording by more than 90%. Folding a mono source down from stereo halves the result again. The work runs locally, so there is no length limit.
At a glance
| Accepts | MP3, WAV, M4A, AAC, FLAC, OGG |
|---|---|
| Produces | MP3 (LAME) |
| Processing | In your browser |
| Price | Free, no limits |
| Account | Not required |
Two things make an audio file bigger than it needs to be: an uncompressed format and a bitrate chosen for music when the content is speech. A WAV recording carries about 10 MB per minute; the same material at 96 kbps MP3 is under 1 MB per minute and sounds no different on a phone speaker or in a car.
128 kbps is the sensible default for general listening. Drop to 96 or 64 kbps for interviews, lectures and voice memos, where the extra bitrate is spent on frequencies the recording never contained. The mono option is the other big lever — a single-microphone recording stored in stereo is carrying two copies of the same signal.
How to use it
- 1
Add your audio file
Drop in an MP3, WAV, M4A, FLAC or OGG file. It stays on your device.
- 2
Choose a target bitrate
128 kbps suits most material. Pick 96 or 64 kbps for speech, 192 kbps for music you want to keep.
- 3
Decide on mono
Leave it as stereo for music. Fold a voice recording to mono to halve the size again.
- 4
Download the MP3
Save the compressed file. The original is untouched.
Frequently asked questions
How much smaller will the file be?
It depends on the source. A 320 kbps MP3 at 128 kbps loses about 60%. A WAV file loses over 90%, because WAV stores no compression at all. Adding the mono option halves whatever is left for a stereo source.
Does compressing audio lose quality?
Yes, MP3 is lossy. At 128 kbps and above the loss is inaudible to most listeners on most equipment. Below 96 kbps cymbals and sibilance start to sound grainy, which is why those settings are labelled for speech.
Can I compress a file that is already an MP3?
Yes, and it works, but it is a second lossy generation — quality that was already discarded cannot come back. Compress from the highest-quality original you have whenever one exists.
Is my audio uploaded to a server?
No. The compression runs inside your browser using WebAssembly. No copy of the file is transmitted, stored or seen by anyone else.
Which formats can be compressed?
MP3, WAV, M4A, AAC, FLAC, OGG, Opus and WMA can be read, as can the audio track of a video file. The output is always MP3, which plays everywhere.