MP3 compressor that works on any device: make MP3 and other audio files smaller for email, messages, uploads and storage. Pick Small file, Balanced or High quality, see the new size before you start, then download. It’s free, there’s no sign-up, and your file never leaves your device.
How to use the MP3 compressor
- Tap Choose file and pick your MP3 or other audio file.
- Choose Small file, Balanced or High quality. The original size, the new size and the saving are shown straight away.
- Press Compress audio.
- Listen to the result to check the quality, then press Download MP3.
Which setting should I choose?
- Small file (64 kbps MP3). The smallest files. Great for speech, voice notes, lectures and audiobooks.
- Balanced (128 kbps MP3). Half the size of most music files with quality that sounds fine on phones and in the car.
- High quality (192 kbps MP3). For music you care about, while still saving space on large files.
Under Advanced settings you can choose the exact bitrate, save as M4A, OGG or OPUS instead of MP3, and switch to mono. Mono sounds noticeably better for voice recordings at small sizes, because all the data goes into one channel instead of two.
Why use this MP3 compressor?
Large audio files get rejected by email, take ages to send in messages, and fill up phones. This MP3 compressor shows you exactly how much smaller your file will be before you press the button, and it warns you if your file is already compressed so far that a setting won’t help. It works on WAV, M4A, FLAC and other formats too, turning them into compact MP3s.
How the MP3 compressor works
Audio file size depends mostly on the bitrate: how much data is used for each second of sound. This tool uses FFmpeg, the free, open-source engine behind many professional audio apps, to re-save your audio at a lower bitrate. It runs inside your browser, so your file is compressed on your own device and is never uploaded.
Tips for compressing audio
- Start with Balanced. It halves the size of most music files and sounds fine on phones, laptops and in the car. Only drop to Small file if you need to.
- Use Small file and mono for speech. Voice recordings, lectures and audiobooks sound clear at 64 kbps in mono, and the files are tiny.
- Compress once, from the best copy. Each time audio is compressed a little detail is lost, so always start from your original, highest-quality file rather than an already compressed one.
- Check email limits. Many email services reject attachments over about 20 to 25 MB. An hour of speech on Small file is around 30 MB, so trim long recordings first with the cutter.
- Listen before you download. The player on the result lets you check the quality in a few seconds.
For very long recordings, a computer is faster than a phone, but both give exactly the same result. The MP3 compressor never adds watermarks, intros or ads to your audio.
More free audio tools
- MP3 Cutter: Cut MP3s and make ringtones
- Audio Trimmer: Trim WAV, M4A and other recordings
- MP3 Converter: Turn WAV, M4A or FLAC files into MP3
- Audio Converter: Convert between MP3, WAV, M4A, FLAC, OGG and OPUS
- MP4 to MP3 Converter: Get the sound from an MP4 video
- Video to MP3 Converter: Extract audio from MOV, WebM and MKV videos
MP3 compressor FAQ
How much smaller will my file be?
It depends on your original file. A typical 320 kbps song becomes about 60% smaller on Balanced and 80% smaller on Small file. WAV files often become 90% smaller or more. The exact saving is shown before you compress.
Will compressing lower the quality?
Some detail is removed to make the file smaller. On Balanced and High quality most people can’t hear a difference on a phone or in the car. Listen to the result before downloading and choose a higher setting if needed.
Can I compress WAV, M4A or FLAC files?
Yes. Any audio format the tool can open can be compressed, and the result is saved as MP3 unless you choose another format in Advanced settings.
Is this MP3 compressor free?
Yes. There’s no account, no watermark and no limit on how many files you compress.
Are my files uploaded?
No. Compression happens in your browser on your own device. Nothing is uploaded or stored.
Need to remove part of the file first? Use the MP3 cutter to trim it, or the audio converter to change its format.
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