Online MP3 Compressor
A free MP3 compressor that shrinks a track by re-encoding it at a lower bitrate — handy when a file is too big to email, your phone is short on storage, or you just want a faster upload. Choose a target bitrate and see the estimated size before you commit. It runs in your browser: nothing to install, no account to create.
Drop your MP3 file here
or click to browse
.mp3, .wav, .aac supported64 kbps
Smallest file
Voice notes, audiobooks
128 kbps
Good balance
Casual music listening
192 kbps
Recommended
Music quality streaming
Bitrate is the main size-and-quality lever
An MP3’s size is set almost entirely by its bitrate — the number of kilobits per second the file spends describing the sound. A three-minute song at 320 kbps is about four times the size of the same song at 80 kbps, because it is storing four times as much detail per second. Compressing an MP3 means re-encoding it at a lower bitrate, which is why the file gets smaller and why the estimate above changes as you move between settings.
The right number depends on what you are listening to. Music benefits from a higher bitrate because there is more going on; speech survives at a much lower one because a voice is simple by comparison. Use this guide as a starting point:
| Bitrate | Quality & size | Best for |
|---|---|---|
| 320 kbps | Best quality, largest file | Music you want to keep at full fidelity |
| 192 kbps | Balanced, noticeably smaller | Everyday music where size matters a little |
| 128 kbps | Small file, decent for casual listening | Sharing, phone storage, background music |
| 64 kbps | Smallest, audible quality drop on music | Voice notes, audiobooks, lectures |
A simple rule: never set the bitrate higher than the original. If a file is already 128 kbps, re-encoding it to 320 kbps only makes it bigger without adding any detail back — the missing information is gone for good.
When to compress — and when to leave a file alone
Compress when…
- ✓ The file is too big for an email attachment
- ✓ Your phone or drive is running low on space
- ✓ You want a faster upload or quicker sharing
- ✓ It is speech, where a low bitrate is barely noticeable
Keep the original when…
- ✗ It is a master or archival copy you may need later
- ✗ You care about critical, high-fidelity listening
- ✗ The file is already at a low bitrate
- ✗ Storage and bandwidth simply are not a problem
One honest limitation
Compression re-encodes the audio, so a little quality is always lost — you cannot shrink an MP3 without giving up some fidelity. Compressing a file that is already at a low bitrate is the worst case: it stacks a second round of loss on the first, and the result can sound muddy or watery. When there is any chance you will want the full-quality version again, keep the original and compress a copy.
Free, and no account needed
There is no signup, no watermark and no cap on how many files you compress. Choose a file, pick a bitrate, preview the estimated size, and download the smaller MP3 — that is the whole flow.
Last updated: July 2026
Frequently Asked Questions
Everything you need to know