How to compress an audio file and reduce its size
Add your file
Drop in an MP3, WAV, M4A or OGG file. It's decoded on your device; nothing is uploaded.
Choose a level
Pick a compression level. Lower bitrates and mono make the file smaller — ideal for voice, email attachments and messaging apps.
Download
See the new file size, then download your smaller MP3 file. The original on your device is never changed.
How audio compression reduces file size
The size of an audio file mainly comes from its bitrate — how many kilobits of data are used per second of sound. A lower bitrate stores less detail, which makes the file smaller. For music, 128 kbps is a good balance most people can't distinguish from the original; for spoken word like podcasts, audiobooks or voice memos, 64 kbps or even lower is usually plenty. You can shrink a file even further by converting stereo to mono (halves the channels) and by lowering the sample rate, both of which are especially effective for voice recordings where high-fidelity stereo isn't needed. This tool re-encodes your audio to MP3, the most widely supported compressed format, so the result plays everywhere.
When to compress an audio file
You'll reach for an audio compressor whenever a file is too large for where it needs to go. Common cases: an email attachment that bounces back for exceeding a size limit, a voice recording or podcast episode that's slow to upload, a song you want to fit more of onto a device with limited storage, or a WAV export from recording software that's far bigger than it needs to be. Compressing an MP3 file to a lower bitrate, reducing an MP3's size for messaging, or converting a large WAV to a compact MP3 all solve the same problem — a smaller file that's quicker to send and store. For music, a moderate level keeps the sound clean; for a spoken-word file like a lecture or interview, you can compress a song or voice recording much harder and still keep it perfectly listenable.
Why is the output always MP3?
MP3 is a compressed format, so it's dramatically smaller than the original — that's the whole point of a compressor. If you need a WAV file instead, use the Audio Converter, which can save any audio as WAV or MP3.
Is my file uploaded anywhere?
No. Compression happens entirely in your browser using the Web Audio API. Your file never leaves your device, which makes it faster and completely private.
How do I make an audio file smaller for email or WhatsApp?
Choose a stronger compression level — 96 or 64 kbps — and, for voice, switch to mono. The size card shows the new size instantly, so you can dial it in to fit an attachment limit before downloading.
Will compressing reduce the audio quality?
Some detail is removed to shrink the file — that's how compression works. At moderate levels the difference is hard to hear, especially for speech. Lower bitrates trade more quality for a smaller size, so pick the level that fits your needs.
What's the smallest I can make a voice recording?
For spoken word, combining a low bitrate (48–64 kbps) with mono and a 16–22 kHz sample rate produces a very small file that still sounds clear. These settings aren't suitable for music, but they're ideal for podcasts, lectures and voice notes.
Can I compress a WAV file?
Yes. WAV files are uncompressed and often very large, so converting one to a compressed MP3 typically produces a dramatic size reduction with little audible difference.
Does this change the original file?
No. The tool creates a new compressed copy for you to download; the original file on your device stays exactly as it was.