About the Audio Compressor
Audio Compressor makes a sound file smaller by saving it again at a lower bitrate. Pick Smallest, Balanced or High quality, choose M4A (AAC) or OGG (Opus) and, if you like, convert to mono. The page shows the size you can expect before you start, then plays the result so you can listen. A long uncompressed WAV can shrink to a tenth of its size, while an MP3 is reduced by lowering its bitrate. Everything happens in your browser, so your recordings are never uploaded.
Updated October 2026
How to use the Audio Compressor
- 1Select an audio file (MP3, M4A, OGG, FLAC or WAV).
- 2Pick how small you want it: 48, 96 or 160 kbps. The expected size is shown.
- 3Choose M4A (AAC) or OGG (Opus), and mono if the recording is a voice.
- 4Press Compress audio.
- 5Listen to the preview and download the smaller file.
Which level to choose
The three levels are bitrates: 48, 96 and 160 kilobits per second. Higher bitrates keep more detail and make bigger files. Mono saves a further 40 percent on top of that, because there is only one channel to store.
- 48 kbps (mono): speech, lectures, audiobooks, voice notes
- 96 kbps: most music on phones and in the car
- 160 kbps: music for good headphones and speakers
Compressing WAV and FLAC
WAV stores every sample without any saving, about 10 MB for each minute of stereo CD quality sound. FLAC is lossless but still large. Both can be reduced a lot by moving to AAC or Opus. Keep the original if you may edit it again later, because each time a file is compressed it loses a little more detail.
Compressing MP3 and other lossy files
A file that is already compressed will not shrink as dramatically, and converting it again lowers the quality a bit more. Aim for a bitrate clearly below the file's current one, and listen to the result. If the file is smaller than your target already, you may not need this tool at all.
Why M4A or OGG instead of MP3
AAC and Opus are newer than MP3 and make better sounding files at the same bitrate. A 96 kbps AAC file often sounds close to a 128 kbps MP3. M4A is the safe choice for sending by message or email. OGG with Opus is excellent for voice and for websites.
Before and after
Cut away silence or unwanted parts first with Audio Trimmer or Audio Silence Remover, so you do not spend bytes on them. If you need an uncompressed copy of the result, Audio to WAV Converter does that, and Audio Joiner combines several recordings into one file before you shrink it.
Features
- Three clear quality levels with a size estimate
- M4A (AAC) or OGG (Opus) output
- Optional mono for voice recordings
- Handles MP3, M4A, AAC, OGG, Opus, FLAC and WAV
- Preview before you download
- No upload and no limits on how often you use it
Frequently asked questions
How much smaller will my file get?
The page shows an estimate from the bitrate and the length. As a guide, a 3 minute song at 96 kbps is about 2.2 MB, and an hour of speech at 48 kbps mono is about 13 MB. A WAV file shrinks the most, often to a tenth.
Does compressing reduce the quality?
Yes, a little. Lossy compression removes detail that is hard to hear. At 96 kbps most music still sounds good on phones and speakers, and 48 kbps is fine for speech. If the file is already small, compressing further may sound worse than the size saved is worth.
Can it make MP3 files?
No. This tool saves M4A (AAC) or OGG (Opus), which sound better than MP3 at the same size. M4A plays almost everywhere; OGG is smaller but a few older players cannot open it.
Will a compressed MP3 get smaller?
Yes if the new bitrate is lower than the old one. Re-compressing a 128 kbps MP3 at 160 kbps makes it bigger, not smaller, so pick a level below the original.
What does mono do?
It mixes the left and right channels into one, which cuts the bitrate needed. It suits voice recordings, lectures and podcasts, but music loses its stereo width.
Can I compress several files at once?
This page does one file at a time. Open it again for the next file; each takes only a short time.
What is kbps?
Kilobits per second: how much data is spent on each second of sound. Higher means better quality and a bigger file.
Is my audio uploaded?
No. The audio is decoded and saved again inside your browser, so voice notes, interviews and music stay on your device.