Compress an Audio File

Compress audio in your browser

Pick an audio file and a target bitrate — it's re-encoded with ffmpeg, entirely in your browser, and comes out smaller. The default 96 kbps MP3 roughly halves a typical 192 kbps music file and cuts a 320 kbps one to less than a third, while staying pleasant to listen to. For voice recordings, podcasts and lectures you can go down to 64 kbps (or even 32) with little practical loss.

Worked example

A 7 MB lecture.m4a phone recording that's too big to email: upload it, set Target bitrate to 64 and leave Output format on mp3 — the result lecture-compressed.mp3 lands around 2 MB, and speech at 64 kbps still sounds clean. For a music file, stay at 96 or use 128 if you can hear artifacts.

Picking a bitrate

• 32–48 kbps — smallest files; fine for voice notes you just need to keep.
• 64 kbps — the sweet spot for speech: podcasts, lectures, interviews.
• 96 kbps (default) — casual music listening, big savings.
• 128–192 kbps — music that should stay close to the original.

The bitrate must be between 32 and 320 kbps — values outside that range are rejected rather than silently adjusted.

Limits and edge cases

• Input files up to 10 MiB; any format ffmpeg can decode works (mp3, wav, m4a, ogg, flac, and more).
• Compression is lossy and works by throwing away detail — it can't be undone, so keep the original if it matters. Re-compressing an already low-bitrate file degrades it further without saving much.
• If the source is already at or below the target bitrate, the output won't get meaningfully smaller — pick a lower bitrate instead.
• Output formats are lossy only (mp3, ogg, m4a). Converting to lossless wav/flac never shrinks a file — use the audio-convert tool for that.
• Embedded album art is dropped; it's often a surprising chunk of small files' size.

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