Compress audio online
Drop in a file in any audio format and it is re-encoded to a smaller size right in your browser. No software to install.
Select the files you want to compress or convert and upload them here.
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Supported compression and conversion formats:
JPEG, JPG, PNG, GIF, WEBP, MP3, TIFF, TIF, BMP, DIB, RLE, JP2, JPF, JPG2, JPX, J2K, JPC, MJ2, OGG, OGV, SPX, WAV, 3GP, AAC, M4A, M4B, OPUS, OGA, MP4, AVI, MKV, MKA, SVG, EXR, RAW, ARW, SRF, SR2, CRW, CR2, CR3, DNG, DCR, KDC, ERF, 3FR, MEF, MRW, NEF, NRW, ORF, PEF, RAF, RWL, RW2, SRW, X3F, PDF, JXL.
What actually determines the size
Audio size is bitrate — how many kilobits go into every second of sound. Multiply bitrate by duration and you get the file size to within a couple of percent: 320 kbps is about 2.4 MB per minute, 128 kbps about 0.96 MB, 64 kbps about 0.48 MB.
So compressing audio means re-encoding it at a lower bitrate. The codec throws away what the ear does not register anyway: quiet sounds masked by loud ones, frequencies above hearing, the difference between channels. Up to a point this is inaudible; past it you start hearing the familiar swirl on cymbals and sibilants.
Music and speech need different numbers
Music wants 128–192 kbps in stereo — below that cymbals and high frequencies fall apart. Speech — a lecture, an interview, a voice memo — is perfectly clear at 32–64 kbps in mono, which makes the file roughly ten times lighter. Picking by content rather than by habit is the whole trick.
What you give up
The honest answer to "compress audio without losing quality" is that you cannot. MP3, AAC, OGG and OPUS all discard data permanently. Truly lossless means a ZIP archive, and on music that buys you 3–5%.
The second rule: never compress twice. Each pass stacks its artefacts on top of the previous ones, and the file degrades far faster than a single pass straight down to the bitrate you need. Keep the original, compress a copy for the job at hand.
| Bitrate | Per minute | Per hour | Good for |
|---|---|---|---|
| 320 kbps | 2.4 MB | 137 MB | music, no compromises |
| 192 kbps | 1.4 MB | 82 MB | music for headphones and speakers |
| 128 kbps | 0.96 MB | 55 MB | background, car, messengers |
| 64 kbps, mono | 0.48 MB | 27 MB | lecture, interview, podcast |
| 32 kbps, mono | 0.24 MB | 14 MB | voice memo, audiobook |
By format
Common questions
How do I compress audio to a specific size?
Divide the target size by the duration. A 40-minute recording under a 25 MB limit fits at 80 kbps; under an 8 MB limit it needs about 25 kbps, which means mono and audible degradation. Pick the nearest value from the table above.
How do I compress audio without losing quality?
Only by archiving it, which buys 3–5% on audio. Everything else is a trade-off: at 192 kbps the difference is inaudible on normal headphones, at 128 kbps it shows on complex music, and speech stays clear even at 32 kbps.
What bitrate should I use for voice?
32–64 kbps in mono. Speech occupies a narrow band and does not need stereo: a two-hour lecture at 48 kbps weighs about 40 MB instead of 200 MB at 192 kbps.
Can I compress several files at once?
Yes. Upload them together or as a ZIP archive — the archive is unpacked automatically, every file is processed, and the result comes back as an archive.