MultiKit

MP3 Converter: Convert WAV, M4A, FLAC, OGG or Video to MP3

  • Free
  • No sign-up
  • Runs in your browser
  • Version 1.0.2
  • Last updated 2026-11-02
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Turn almost any sound file, or the sound of a video, into an MP3 that plays on every phone, car stereo and player. Choose the bitrate, and nothing leaves your device.

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 the file onto the box, or choose it. WAV, M4A, AAC, OGG, FLAC and the common video files are accepted.
    2. MP3 is already chosen. Choose the quality: 128 kbps for speech, 192 kbps for most music, 320 kbps for the best.
    3. Press Convert and then Download. To keep only a part, type a start and an end first.

    Examples

    recording.wav, 5 minutes, to MP3 at 192 kbps
    → recording.mp3, about 7.2 MB
    The WAV was about 53 MB; 192,000 × 300 ÷ 8 is 7.2 MB.
    interview.m4a, to MP3 at 64 kbps, mono
    → About 0.5 MB per minute
    Enough for speech.
    lecture.mp4, to MP3 at 128 kbps
    → lecture.mp3 with the sound only
    The picture is left out.
    A one-hour podcast at 128 kbps
    → About 57.6 MB
    128,000 bits a second × 3,600 seconds ÷ 8. At 64 kbps it is half of that, 28.8 MB.
    A 4-minute song at 320 kbps
    → About 9.6 MB
    The size depends only on the bitrate and the length, not on the song.
    My Song.final.WAV
    → My Song.final.mp3
    Only the last extension is replaced.

    How it works

    This page is the audio converter with MP3 already chosen. The file is decoded by the WebCodecs of your browser, through the open-source Mediabunny toolkit, and encoded by 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. 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.

    Choosing a bitrate

    The bitrate is how many bits of sound are stored per second, and it is the one number that sets the size of the file. The page offers 64, 96, 128, 160, 192, 256 and 320 kbps and starts at 192.

    Bitrate One minute One hour Suits
    64 kbps 0.48 MB 28.8 MB Speech and voice notes, with mono
    128 kbps 0.96 MB 57.6 MB Podcasts, audiobooks, background music
    192 kbps 1.44 MB 86.4 MB Most music
    320 kbps 2.4 MB 144 MB The best an MP3 can give

    What converting does to the sound

    An MP3 keeps what is easiest to hear and drops the rest, so the conversion is one way: a WAV can become an MP3, but the MP3 cannot give back the detail that was removed. Starting from a lossless file such as WAV or FLAC gives the best MP3; starting from another lossy file such as M4A means the sound has been compressed twice. If you only need a quieter, smaller copy of an MP3, pick a lower bitrate, and keep the original.

    Playing it everywhere

    MP3 is the format that nearly every phone, car stereo, speaker and program plays, which is the whole reason to convert to it. If a device accepts only another format, the same screen can write M4A, OGG, WAV or FLAC, depending on your browser.

    Sources

    Frequently asked questions

    What bitrate should I use for MP3?
    128 kbps is a good size for speech and podcasts, 192 kbps is hard to tell from the original for most music, 256 to 320 kbps is for the best result. Higher means a larger file.
    Is the MP3 encoder good?
    It is LAME, the encoder most MP3 files in the world were made with, running in your browser as WebAssembly.
    Does MP3 lose quality?
    Yes: MP3 discards the parts of the sound that are hardest to hear to make the file small. At 192 kbps and above it is very hard to notice. Converting an MP3 to MP3 again loses a little more.
    Can it join several files?
    No. It converts one file at a time.
    Is my file uploaded?
    No. It is converted in your browser.
    How big will the MP3 be?
    Bitrate times length, divided by 8. A kilobit is 1,000 bits, so 192 kbps is 24,000 bytes a second, 1.44 MB a minute. A CD-quality WAV is 1,411 kbps, about 10.6 MB a minute, so an MP3 at 192 kbps is about a seventh of it.
    What does the mono option do?
    It mixes the sound down to one channel before encoding. The size still follows the bitrate and the length, so the saving comes from choosing a lower bitrate: with one channel, 64 kbps is usually clear enough for speech. Use it for speech, voice notes and recordings from a single microphone. Music loses its stereo picture.
    Why does converting an MP3 to an MP3 change the file?
    The sound is always decoded and encoded again, even when the format is the same, so the file is rewritten at the bitrate you choose. That is useful for making a smaller copy, and a little quality is lost each time, so keep the original.
    Which files can I convert?
    Common sound files and the sound of common video files: WAV, M4A, AAC, OGG, FLAC, MP4, MOV and WebM among them. What a given browser can read depends on the browser, and the page says so if it cannot read a file. Chrome and Edge read the most.
    How large can the file be?
    Up to 2 GB, because the browser holds the file while it works.

    Guides

    Version history
    • 1.0.2 — Adds a bitrate table with the size per minute and per hour, what converting does to the sound, what the mono option does, and more examples and questions.
    • 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: