MP3 Compressor
This MP3 compressor makes audio small enough to attach, send or keep. Free and unlimited, no sign-up, and the file is processed on your own device.
Your file is converted in your browser and never uploaded to our servers.
How to Compress MP3 Files Here
- 1
Add the audio file
Choose an MP3, or a WAV, M4A, AAC, OGG or FLAC file. The MP3 compressor accepts all of them and always returns an MP3.
- 2
Pick 64, 96 or 128 kbps
96 kbps is preselected and suits podcasts and everyday listening. Go to 64 kbps for voice notes, or 128 kbps for music.
- 3
Press Compress MP3 and check the numbers
The result shows the original size, the new size and the percentage saved. The download is named like song-compressed.mp3, so the original keeps its name.
Why This MP3 File Compressor
Savings we measured
In our test, the MP3 compressor made a 192 kbps file 67% smaller at 64 kbps, 50% smaller at 96 and 33% smaller at 128. You see your own figure the moment the file is done.
Nothing leaves your device
This MP3 compressor is FFmpeg built for WebAssembly, running inside the browser tab. Your recording is read from disk and never sent to a server.
No caps on use
No account, no daily allowance and no paid tier for bigger files. Compress one file, then the next, as often as you need.
Any audio in, MP3 out
WAV, FLAC and M4A files are accepted too. That makes this page a quick WAV compressor when a recorder or DAW leaves you with a file too big to share.
Which Bitrate to Pick When You Compress MP3
Savings come from running our MP3 compressor on a 192 kbps test file. Minutes per 10 MB are worked out from the bitrate, so treat them as approximate.
| 64 kbps | 96 kbps (default) | 128 kbps | |
|---|---|---|---|
| Best for | Speech, voice notes | Podcasts, general use | Music |
| Smaller than a 192 kbps MP3 | 67% (measured) | 50% (measured) | 33% (measured) |
| A 30 MB file at 192 kbps becomes | About 10 MB | About 15 MB | About 20 MB |
| Audio per 10 MB | About 20 min | About 14 min | About 10 min |
| What you may notice | Duller highs; fine for talk | Slight softness on music | Fewest artifacts of the three |
When You Need to Compress an Audio File
People reach for an MP3 compressor when they hit a limit: an upload field, a chat app, a page budget or a full phone.
Upload forms with a size cap
Job applications, course portals and contest entries often reject audio over a set size. Drop the bitrate until the file clears it.
Messaging apps
Many apps and sites cap uploads, so a long recording can simply be refused. A 64 kbps voice memo is a fraction of the size and still easy to follow.
Audio on a website
A lighter MP3 starts playing sooner for visitors and costs less hosting bandwidth. 96 kbps is a sensible level for spoken audio on a page.
A phone that is full
Lectures, sermons and audiobook rips you only listen to once take far less room at 64 kbps than as 192 kbps or 320 kbps rips.
Meeting and interview recordings
Long talks are mostly voice. By the bitrate math, an hour at 64 kbps is about 29 MB, small enough for a shared folder or a team chat.
Lesson audio for students
Recorded lessons and pronunciation drills at 64 or 96 kbps download quickly on mobile data and play in any browser.
Compressing Audio Size Is Not the Compressor Effect
Compress means two different things in audio. In mixing, a compressor is an effect that narrows the gap between loud and quiet parts. It changes how a track sounds, not how many megabytes it takes. This page does not do that.
An MP3 compressor in the file-size sense re-encodes the audio at a lower bitrate. The LAME encoder spends fewer bits per second and drops detail the ear is least likely to miss, so the file shrinks and some quality goes with it.
Zipping is a third thing. MP3 data is already compressed, so putting it in a ZIP archive barely changes its size. Lowering the bitrate is what actually makes an MP3 smaller.
Mistakes That Waste an MP3 Compressor Run
Mistake: Compressing an MP3 that is already 64 or 96 kbps to the same level.
Do this instead: Pick a bitrate below the file's current one. At or above it, the output stays about the same size or grows, and you only lose quality.
Mistake: Running the same file through again and again.
Do this instead: Every lossy pass adds artifacts. Start from the original and choose the lower bitrate once.
Mistake: Using 64 kbps for songs you care about.
Do this instead: Cymbals and reverb tails turn swishy at low rates. Keep music at 128 kbps.
Mistake: Overwriting the original with the smaller copy.
Do this instead: The MP3 compressor saves a separate -compressed.mp3 file. Keep the source for the day you need full quality.
Mistake: Zipping the MP3 to get under a limit.
Do this instead: A ZIP of an MP3 is nearly as large as the MP3. Re-encode at a lower bitrate instead.
Privacy, Cost and Honest Limits
Processed in your browser
The first time you use the MP3 compressor, the page downloads the converter once, about 9 MB, and the browser caches it. The audio itself never goes to our host or to anyone else.
Free, with no limit on files
There are no plans or upgrades. Every option on this page is available without signing up.
What it can't do
One file at a time, three fixed bitrates, no target-size slider and no mono switch, so stereo stays stereo. Very large files may fail on a phone with little memory; use a computer for those.