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Audio compressor

Developer tools

Smaller audio, same listening

Re-encode WAV, MP3, M4A or FLAC to MP3, AAC or Opus at a bitrate you choose, with the new size shown before you save.

Drop audio files or browseWAV, MP3, M4A, AAC, FLAC, OGG or WebM — encoded in your browser, nothing uploaded
Presets

    About this tool

    The one media type that was missing

    Podcast episodes, voice notes and site audio are routinely exported far larger than they need to be — a WAV is ten times an MP3, and a 320 kbps MP3 of speech is four times what speech needs. This decodes your audio in the browser and re-encodes it to MP3 (plays everywhere), AAC in M4A (Apple’s default) or Opus (best quality per byte), at a bitrate you choose, optionally to mono. The estimated size updates as you change settings.

    • Free, no sign-up
    • Runs in your browser
    • Nothing uploaded

    Three codecs

    MP3 for compatibility, AAC for Apple and video, Opus for the best quality per byte at low bitrates.

    Size first

    Bitrate × duration decides the size; you see the estimate before encoding, and the exact size after.

    Speech presets

    Voice sounds clean at 48–64 kbps mono. One click sets it.

    Step by step

    How to compress an audio file

    1. Add your audio

      Drop WAV, MP3, M4A, AAC, FLAC, OGG or WebM audio — one file or several.

    2. Choose codec and bitrate

      MP3 for anywhere, AAC for Apple, Opus for smallest. Pick a bitrate, or a preset for speech or music.

    3. Download

      Encode, play the result to check it, and download.

    Get the most out of it

    Tips for the best results

    • Speech needs little64 kbps mono is clear for podcasts and voice notes.
    • Music needs more128–192 kbps stereo AAC or MP3 is transparent for most listeners.
    • Do not re-compress twiceEach lossy encode loses a little; start from the best source you have.
    • Mono halves itIf the recording is a single voice, mono costs nothing audible.

    Keep going

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    Questions

    Questions about this tool

    Everything here runs in your browser — nothing you add is uploaded. More in the general FAQ.

    How do I reduce an MP3 file size?

    Re-encode it at a lower bitrate: drop it here, choose MP3 and a bitrate such as 96 or 128 kbps (64 kbps mono for speech), and download. The size estimate shows the result before you encode.

    What bitrate should I use?

    Speech: 48–64 kbps mono. Music: 128–192 kbps stereo. Opus sounds noticeably better than MP3 at the same low bitrate.

    Which format is smallest?

    Opus, at any given quality, followed by AAC and then MP3. MP3 remains the most compatible.

    Can I convert WAV to MP3?

    Yes — drop the WAV and choose MP3. A WAV is uncompressed, so the MP3 is typically 85–95% smaller.

    Is my audio uploaded?

    No. Decoding and encoding run in your browser.