Is this audio compressor free to use?

Yes, completely free — no account, no subscription, no hidden fees. Open the page and compress as many files as you like.

Is my audio file uploaded to a server? Is it safe?

No upload, ever. The entire compression runs inside your browser using ffmpeg.wasm. Your audio file never leaves your device and is never accessible to any server or third party.

Which bitrate should I choose?

For voice, podcasts, and audiobooks 64-96 kbps is usually enough. For music you want to preserve quality, 128 kbps is a good balance. Use 192 kbps or higher only when quality is more important than file size.

How much smaller will my file be after compression?

It depends on the original bitrate. Compressing a 320 kbps MP3 down to 128 kbps cuts the file to about 40% of its original size. Going from 128 kbps to 64 kbps halves the size again. The result will always be smaller than the source when you pick a lower bitrate.

Does it work on mobile?

Yes. The tool runs in any modern browser, including Chrome and Safari on Android and iOS. Processing time may be slightly longer on mobile devices due to slower CPU performance compared to desktop.

🗜️ Audio Compressor — Reduce MP3 Size, Free & Private

Reduce your audio or MP3 file size instantly by selecting a lower bitrate — everything runs client-side in your browser using ffmpeg.wasm, so your audio is never uploaded and stays completely private. Free, no sign-up required, and works offline once the page loads.

Choose an audio file

Bitrate (quality)

Private by design. This tool runs entirely in your browser — nothing you enter is uploaded or stored, and it works offline.

About

This audio compressor uses ffmpeg.wasm — a WebAssembly port of the industry-standard FFmpeg library — to re-encode your audio file at a lower bitrate entirely inside your browser. Lower bitrates produce smaller files; a 128 kbps MP3 is roughly half the size of a 320 kbps original while remaining perfectly listenable for most uses. Because processing happens 100% client-side, your audio file never leaves your device, is never stored on any server, and is not accessible to anyone else. The tool supports common audio formats including MP3, AAC, OGG, WAV, and FLAC, and outputs a compressed MP3 file ready to download.

How to use

Click "Choose File" and select the audio or MP3 file you want to compress from your device.
Pick a target bitrate from the dropdown — lower values (e.g. 64 kbps) give a smaller file; higher values (e.g. 192 kbps) preserve more quality.
Click "Compress" and wait a few seconds while ffmpeg.wasm re-encodes the audio in your browser.
Click "Download" to save the compressed MP3 file to your device.

FAQ

Is this audio compressor free to use?: Yes, completely free — no account, no subscription, no hidden fees. Open the page and compress as many files as you like.
Is my audio file uploaded to a server? Is it safe?: No upload, ever. The entire compression runs inside your browser using ffmpeg.wasm. Your audio file never leaves your device and is never accessible to any server or third party.
Which bitrate should I choose?: For voice, podcasts, and audiobooks 64-96 kbps is usually enough. For music you want to preserve quality, 128 kbps is a good balance. Use 192 kbps or higher only when quality is more important than file size.
How much smaller will my file be after compression?: It depends on the original bitrate. Compressing a 320 kbps MP3 down to 128 kbps cuts the file to about 40% of its original size. Going from 128 kbps to 64 kbps halves the size again. The result will always be smaller than the source when you pick a lower bitrate.
Does it work on mobile?: Yes. The tool runs in any modern browser, including Chrome and Safari on Android and iOS. Processing time may be slightly longer on mobile devices due to slower CPU performance compared to desktop.