Quick answer: To compress an MP3, add it here, keep 128 kbps and press Compress MP3. A 320 kbps file shrinks by about 60 percent, to roughly 1 MB per minute. MP3s that are already 128 kbps or lower will not get smaller, and the page shows the estimated size before you start. Nothing is uploaded.
MP3s saved at 256 or 320 kbps are two to three times bigger than they need to be for speech, audiobooks or background music. Re-encode them at a lower bitrate for email, chat apps and small players.
Compress MP3 at a glance
| Price | Free, no sign-up, no watermark, no daily limit |
|---|---|
| Accepts | MP3 |
| Largest file | 1 GB per file, several files at once |
| Where it runs | In your browser: files are never uploaded |
| Works on | Any modern browser on iPhone, Android, Windows, Mac and Linux |
| Send the result | Download it, or send it free with a link or by email (up to 20 GB) |
How to compress MP3
- Choose one or more MP3 files.
- Keep 128 kbps for speech, or choose 192 kbps to keep music closer to the original.
- Compare the estimated size with the original, then press Compress MP3.
- Download the smaller MP3s.
MP3 size is set by the bitrate
An MP3's size is its bitrate times its length, whatever it contains:
| Bitrate | Per minute | One hour | Good for |
|---|---|---|---|
| 320 kbps | 2.4 MB | 144 MB | Music archives |
| 256 kbps | 1.9 MB | 115 MB | Music |
| 192 kbps | 1.4 MB | 86 MB | Music on phones and in the car |
| 128 kbps | 0.96 MB | 58 MB | Speech, podcasts, audiobooks, casual listening |
Compress once, from the best copy
Re-encoding an MP3 decodes it and encodes it again, which adds a little loss each time. Compress from the highest-quality file you have, and do it once. If you still have the original WAV or FLAC, convert that with WAV to MP3 or FLAC to MP3 instead: the result sounds better at the same size.
Other ways to make it smaller
- Cut the silence and the parts nobody needs with Trim audio.
- M4A (AAC) sounds a little better than MP3 at the same bitrate; Convert audio can write it.
- Too big even compressed? A long recording can go as a download link, free up to 20 GB.
How this compares
| This tool | Online converters (e.g. Online Audio Converter, Clideo or CloudConvert) | Desktop apps (e.g. Audacity) | |
|---|---|---|---|
| Your file is uploaded | No | Yes, to their servers | No |
| Install or account | None | Account for some features | Install needed |
| Watermark or daily limits | None | Common on free plans | Depends on the app |
Plans of other services change; check their sites. More audio tools.
Frequently asked questions
How much smaller will my MP3 get?
From 320 kbps to 128 kbps, about 60 percent smaller. From 192 kbps, about a third smaller. A 128 kbps MP3 will not shrink.
Will it sound worse?
Speech and podcasts sound the same at 128 kbps. Music loses a little sparkle in cymbals and reverb; choose 192 kbps if that matters.
Can I go below 128 kbps?
Not on this page: 128 kbps is the lowest option, because MP3 below that gets noticeably worse. For long speech recordings, trimming saves more.
Can I compress a whole album at once?
Yes. Add all the MP3s; they are compressed one after the other and can be downloaded together as a ZIP.
Is my audio uploaded?
No. It is re-encoded in your browser.
Need to send a big file?
Send files up to 20 GB with a download link or by email. Free, no account needed, original quality.
Send large files free