U-01

CONVERT

As a rough guide, files over 1GB are more likely to fail due to device memory limits.
READOUT
— — —

Manual

  1. What CONVERT does

    CONVERT changes the format of an audio file. It can export to WAV, MP3, FLAC, AAC (M4A) and OGG — everything you need to convert wav to mp3 online, or convert flac to mp3, for free. It can also extract just the audio from a video file such as MP4, MOV or WebM (the picture is never included in the output).

    On the input side it accepts a wide range of formats that ffmpeg can read, including WAV, MP3, FLAC, AAC, M4A, OGG, OPUS, AIFF and WMA, plus video files such as MP4, MOV, WebM, MKV and AVI.

  2. How to use it

    (1) Drag and drop a file onto the drop zone, or click it to choose one (multiple files are supported). (2) Pick an output format. For MP3, AAC (M4A) and OGG you can also choose a bitrate (128 / 192 / 256 / 320kbps — higher means better quality and a larger file). (3) Optionally set a sample rate (keep as-is, 44.1kHz, or 48kHz). (4) Press the convert button; each file gets its own progress bar, and a download button appears once it finishes.

    There's no limit on how many files you can select at once. Multiple files are processed one after another, each with its own download button.

  3. Supported formats & bitrate cheat sheet

    Sample rate can be set to keep as-is, 44.1kHz, or 48kHz. On the input side it accepts WAV, MP3, FLAC, AAC, M4A, OGG, OPUS, AIFF and WMA, plus video files like MP4, MOV, WebM, MKV and AVI.

    Output formatExtensionBitrate optionsNotes
    MP3.mp3128 / 192 / 256 / 320kbpsLossy. The most widely compatible choice
    WAV.wav— (uncompressed)Lossless. Large file size
    FLAC.flac— (lossless compression)Lossless with a smaller file than WAV
    AAC (M4A).m4a128 / 192 / 256 / 320kbpsLossy. Plays well across Apple devices
    OGG.ogg128 / 192 / 256 / 320kbpsLossy, Vorbis codec

  4. Use case: turn a recorded meeting into an MP3

    Voice recorders and video-call apps often save WAV files that are too large to email or share in chat. Convert the output format to MP3 at around 128kbps and you'll keep the recording easy to follow while cutting the file size down a lot — a common way to convert wav to mp3 for sharing.

  5. Use case: extract audio from video

    Drop an MP4, MOV, WebM, MKV or AVI file onto the drop zone and CONVERT automatically strips the video stream, writing out just the audio in whichever format you choose (MP3 / WAV / FLAC / AAC (M4A) / OGG). If the video has more than one audio track, the first one is used.

    This tool only extracts audio — it doesn't export video. It's handy for pulling a podcast-ready audio track out of a lecture recording or webinar (an mp4 to mp3 style conversion).

  6. How it works: in-browser processing and privacy

    The conversion happens entirely inside your browser, using a WebAssembly build of ffmpeg. There is no upload step; once it finishes, the result downloads straight to your device.

    The first conversion has to load the conversion engine itself (about 30MB) once, which can take a moment. After that, the page keeps working offline as long as it stays open.

  7. A note on audio quality

    MP3, AAC (M4A) and OGG are lossy formats, so the result can never sound better than the source. Converting an already low-bitrate file to a higher bitrate won't undo the original quality loss. For lossless results, choose WAV or FLAC.

  8. Limits and troubleshooting

    Everything runs in your device's memory, so very large files (as a rough guide, over 1GB) may fail to convert if your device runs out of memory. For long recordings or high-resolution audio, consider splitting the file first.

  9. FAQ

    Are my files uploaded anywhere?
    No. Conversion happens entirely in your browser; files are never sent to a server.
    Do I need an internet connection?
    Only the first time, to download the conversion engine (about 30MB). After that, you can keep converting offline as long as the page stays open.
    Why did my conversion fail?
    The file may be corrupted or in an unsupported format, or it may simply be too large for your device's available memory. Try splitting the file, or re-exporting it in a different format first.
    Which audio track does it use from a video file?
    The first audio track in the file. If a video has multiple language tracks or a commentary track, only the first one is used.
    What happens to the picture when I convert a video?
    It's discarded. CONVERT is an audio-extraction tool, so the output is always an audio file (MP3, WAV, FLAC, AAC/M4A or OGG) — never a video.
    Which video containers are supported?
    MP4, MOV, WebM, MKV, AVI, M4V and most other containers that ffmpeg can read.