Compress audio
Make an audio file smaller by re-encoding it, with the quality you choose.
Drop a file to start
Runs in your browser. Nothing is uploaded.
A recording that arrived as a WAV is carrying every sample uncompressed, which is roughly ten megabytes a minute in stereo. Almost nothing needs that: a lecture, an interview, a voice memo or a podcast episode sounds the same at a tenth of the size, and the tenth is the one that fits in an email or uploads before the meeting ends.
The quality setting is words rather than a bitrate number, because a bitrate means something different in every codec — 128 kbps is thin for MP3 and generous for Opus. Medium is the setting most files want, high is for music you will listen to properly, and low is for speech where the point is the words.
Which format matters more than the dial. Opus is the best of them at any given size and every current browser plays it; MP3 is the one that plays in a car from 2009. The panel shows what the batch weighed before and after, so the trade is a number rather than a hope, and nothing is uploaded to find out — the encoding happens on your own machine.
Step by step
- 1Drop in the files.
- 2Pick a format and how much quality to keep.
- 3Press Convert, then download.
Questions
How much smaller will my file get?
A stereo WAV usually drops by about 90% at medium quality. An MP3 that is already compressed will shrink much less, and re-compressing it costs quality — start from the original if you still have it.
Which format should I pick?
Opus for anything played in a browser or an app: it sounds better than MP3 at the same size. MP3 when it has to play on old hardware. Both are here.
Does compressing twice make it worse?
Yes. Every lossy pass throws away detail permanently, and a second pass throws away more. Keep your original.
Is my audio uploaded?
No. The file is decoded and re-encoded inside this tab using your browser’s own codecs, which is also why it keeps working with the network off.