MP3 Compressor
Reduce the size of MP3 files — and turn WAV, M4A, FLAC or video soundtracks into compact MP3s. Pick a quality, a bitrate or the maximum file size you need. Everything happens in your browser, so even private recordings never leave your device.
- No upload
- Target file size
- A/B compare
- Free, no limits
Drop audio files here
or
You can also paste with Ctrl+V (⌘+V on Mac) or drop a whole folder.
MP3 · WAV · M4A · AAC · FLAC · OGG · OPUS · MP4 / MOV video
Your files are processed on your device and are never uploaded.
This tool needs a recent browser with WebAssembly and Web Workers: Chrome, Edge, Firefox, Safari or Samsung Internet. Please update your browser or try another one.
Done — your files are ready
You changed the settings — click the button again to update the result.
How to compress an MP3 file
Three steps — most files are done in seconds.
- 1
Add your audio
Drop MP3, WAV, M4A, FLAC, OGG or video files onto the page — one or hundreds.
- 2
Pick a size or quality
Choose a preset like 128 kbps, set a bitrate or enter the maximum file size you need.
- 3
Compress & download
Listen to the result, compare it with the original and download each file or a ZIP.
Smaller MP3s that still sound great
A real LAME MP3 encoder — running privately on your device.
Target file size
Need it under 10 MB for an email or 25 MB for Discord? Enter the limit and the best possible bitrate is chosen for each file.
Presets or exact bitrate
One click for 256, 192, 128, 96, 64 or 32 kbps — or choose any bitrate, constant or variable.
Hear the difference
Switch between original and compressed version at the same position before you download.
Perfect for voice
Podcasts, lectures and voice memos shrink up to 90 % at 48–64 kbps mono with clear speech.
Tags stay intact
Title, artist, album, track number and cover art are copied to the compressed file.
Batch processing
Compress up to 100 files at once, see the size of each one in advance and download a ZIP.
100 % private
Your audio is processed in your browser and never uploaded to a server.
Free, no watermark
No sign-up, no watermark, no daily limits, no installation.
How MP3 compression works — and which bitrate to choose
The size of an MP3 file depends almost entirely on its bitrate and its length: a 4-minute song at 320 kbps is about 9.6 MB, at 128 kbps about 3.8 MB and at 64 kbps about 1.9 MB. Compressing an MP3 means re-encoding it at a lower bitrate — the encoder removes details that are hardest to hear.
For music, 128 kbps is a good balance that most people can’t tell apart from the original on phone speakers or earbuds. Choose 192 kbps or more for headphones and good speakers. Speech needs far less: 64 kbps mono sounds clear and makes podcasts and voice memos tiny.
With Target size you don’t need to calculate anything: the tool divides the size limit by the duration of each file and picks the highest bitrate that fits. Re-compressing a file that is already at a low bitrate cannot improve its quality — if the result would be bigger, the original is kept.
MP3 size per minute of audio
| Bitrate | Size per minute | Best for |
|---|---|---|
| 320 kbps | 2.4 MB | Archiving, DJ sets |
| 192 kbps | 1.4 MB | Music on good headphones |
| 128 kbps | 0.96 MB | Music on phones, sharing |
| 96 kbps | 0.72 MB | Background music, previews |
| 64 kbps mono | 0.48 MB | Podcasts, audiobooks, lectures |
| 32 kbps mono | 0.24 MB | Voice memos, very small files |
Tips
- Remove silence at the start, end or in pauses first with the Silence Remover — shorter files are smaller files.
- Cut out only the part you need with the Audio Cutter.
- Want a different format such as M4A or OGG? Use the Audio Converter.
- Uneven volume across files? Fix it with the Volume Normalizer before compressing.
Frequently asked questions
Can’t find your answer? Contact us — we reply quickly.
How do I reduce the size of an MP3 file?
Drop the file onto this page, choose a lower bitrate (for example 128 kbps) or enter a target size, and click “Compress MP3”. Download the smaller file when it’s ready.
Will compressing an MP3 reduce the quality?
Lowering the bitrate removes some detail, but at 128 kbps or more most listeners hear no difference. Use the A/B compare button to check before you download.
How can I make an MP3 smaller than 10 MB (or any limit)?
Switch the mode to “Target size”, enter 10 MB and compress. The tool picks the best bitrate that keeps every file under the limit.
Are my files uploaded to a server?
No. The MP3 encoder runs inside your browser, so your audio never leaves your device. You can even disconnect from the internet after the page has loaded.
Can I compress WAV, M4A or FLAC files too?
Yes. Any audio your browser can read — WAV, M4A, AAC, FLAC, OGG, Opus and the soundtrack of MP4 or MOV videos — is converted to a compressed MP3.
Are ID3 tags and album art kept?
Yes, title, artist, album, genre, track number and cover art are copied by default. Turn off “Keep tags & cover art” under More options to remove them.
What is the difference between CBR and VBR?
Constant bitrate (CBR) uses the same number of bits every second; variable bitrate (VBR) uses more for complex passages and less for simple ones, which usually gives smaller files at the same quality. CBR is the most compatible choice.
Is there a file size or number limit?
No artificial limits. You can add up to 100 files per batch; very long files are only limited by your device’s memory.
More free audio tools
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