MultiKit

Audio Converter: MP3, WAV, M4A, OGG and FLAC, No Upload

  • Free
  • No sign-up
  • Runs in your browser
  • Version 1.0.3
  • Last updated 2026-11-09
Report a problem

Convert a sound file to MP3, WAV, M4A, OGG or FLAC, choose the quality, and keep only the part you want. The sound of a video file works too. It is done by your browser, so the file is never uploaded.

What this browser can make

    This depends on your browser, not on MultiKit. Chrome and Edge support the most.

    Everything you enter is processed in your browser and is never sent to a server.

    Browsers:Chrome94+Edge94+Firefox130+Safari26+Opera80+Samsung Internet17.0+BrowsersWhich formats it can read and write also depends on your browser and device; the tool shows what yours can do.

    How to use

    1. Drop an audio or video file onto the box, or choose it. The length and the format of the file are shown, and you can play it.
    2. Choose the format to convert to. For MP3, M4A and OGG choose the quality: 128 kbps is fine for speech, 192 kbps for most music, 320 kbps for the best. WAV and FLAC are lossless.
    3. To keep only a part, type the start and the end, or play the file and press Start here and End here at the moments you want.
    4. Press Convert, listen to the result and press Download.

    Examples

    A 3-minute song, converted to MP3 at 192 kbps
    → About 4.3 MB
    192,000 bits a second × 180 seconds ÷ 8.
    The same minute as WAV (CD quality)
    → About 10.6 MB per minute
    44,100 samples × 16 bits × 2 channels: WAV is not compressed.
    A recording of speech, MP3 at 64 kbps and mono
    → About 0.5 MB per minute
    64,000 bits a second × 60 seconds ÷ 8. At a set MP3 bitrate the size follows the bitrate and the length, so the low bitrate makes the file small, not the mono option. For WAV, mono does halve the file.
    A 10-minute file, start 2:00, end 3:30
    → A 90-second file
    Times can be typed as 83, 1:23.5, 01:02:03 or 1h2m3s. An empty start means the beginning, an empty end the end.
    my:video?.mov, converted to MP3
    → my_video_.mp3
    The name of the result follows the input. Characters that file names cannot hold become an underscore.

    How it works

    The file is read and decoded by the WebCodecs of your browser, through the open-source Mediabunny toolkit (MPL-2.0), and written in the format you choose. Browsers have no MP3 encoder of their own, so for MP3 the page adds LAME, the standard open-source MP3 encoder (LGPL), built as a separate WebAssembly module that runs in a web worker. LAME is credited at lame.sourceforge.io.

    The five formats

    Format Written as Quality setting
    MP3 MP3 by LAME Bitrate, 64 to 320 kbps
    M4A AAC in an MP4 file Bitrate, 64 to 320 kbps
    OGG Opus, or Vorbis if the browser cannot write Opus Bitrate, 64 to 320 kbps
    WAV 16-bit PCM, not compressed None, lossless
    FLAC FLAC None, lossless

    WAV, M4A, OGG and FLAC use the encoders of the browser when it has them, and the page checks before a conversion what this browser can make and turns off what it cannot, rather than failing later.

    Cutting a part

    The part you keep is cut at the times you type. A start of zero or an empty start means the beginning, and an empty end, or one beyond the length of the file, means the end. The length of what is kept is the end minus the start, and the speed of the conversion depends on your device.

    The time input, the part that is kept, the names of the results, the bitrates and the size per minute are tested.

    Sources

    Frequently asked questions

    Which format should I choose?
    MP3 plays everywhere. M4A (AAC) is a little better at the same size and plays on Apple and Android devices. OGG (Opus) is the most efficient. WAV and FLAC lose nothing: FLAC is smaller, WAV is accepted by every editing program.
    Which quality choices are there?
    For MP3, M4A and OGG you pick a bitrate of 64, 96, 128, 160, 192, 256 or 320 kbps. 192 is chosen at the start. WAV and FLAC have no quality setting, because they lose nothing.
    How big will the file be?
    For MP3, M4A and OGG about the bitrate times the length divided by 8: a minute is about 0.48 MB at 64 kbps, 0.96 MB at 128, 1.44 MB at 192 and 2.4 MB at 320. A minute of WAV from a stereo CD-quality source is about 10.6 MB.
    Does converting lose quality?
    Converting to MP3, M4A or OGG discards some sound to make the file small, and converting a lossy file again discards a little more. Converting to WAV or FLAC loses nothing, but it cannot bring back what an earlier MP3 already lost.
    How do I keep only a part?
    Type the start and the end, or play the file and press Start here and End here. A start after the end of the file, or an end that is not after the start, is refused with a message. An end beyond the file just means its end.
    Why is a format greyed out?
    This page uses the audio and video codecs built into your browser, so what it can read and write depends on the browser. The list under the tool shows what yours can make. Chrome and Edge support the most.
    Is my file uploaded?
    No. It is read and converted in your browser. Close the tab and nothing remains.
    How big a file can it take?
    Up to 2 GB. The result is made in the memory of the tab, so a very long recording needs a computer with enough memory.
    Can it convert the sound of a video?
    Yes. Drop the video file and choose an audio format. The picture is left out.

    Guides

    Version history
    • 1.0.3 — Adds what each of the five formats is written as, the quality choices and the size per minute, how times are typed and the part that is kept, how the result is named, and examples for them.
    • 1.0.2 — Removes the claim that the mono option makes the file smaller: at a set MP3 bitrate the size follows the bitrate and the length, so the label and the example now say so.
    • 1.0.1 — Makes the search title and description state the supported task, key formats and privacy benefit more clearly.
    • 1.0.0 — First release.

    Last updated: