Convert MP4 to MP3 Online — Free, No Upload

Extract the audio track of any video as a high-quality MP3, privately on your device.

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Extract the audio from any video

Lectures, interviews, voice memos recorded as video, music in a screen recording — sometimes you only need the sound. This tool strips the video track and saves the audio as a high-quality MP3 that plays everywhere.

It accepts MP4, WebM, MOV, MKV and AVI files, and the conversion runs entirely in your browser using WebAssembly — your video is never uploaded anywhere, which matters for private recordings and meetings.

How it works (and what to expect)

Drop a video above and press Extract. The first use downloads the conversion engine (about 31 MB, cached afterwards), then audio is extracted at roughly real-time speed — a 3-minute video takes on the order of a minute. For very long recordings, trim the video first and extract just the part you need.

Unlike most online converters, FileLark never uploads your files to a server. The conversion runs entirely inside your browser using modern web technology, which means it works offline once the page has loaded, there are no file size queues or daily upload limits, and your images can never be stored, scanned, or leaked — they simply never leave your device.

Audio quality

The MP3 is encoded at a high variable bitrate (roughly 190 kbps), which is transparent for speech and very good for music. Remember that extraction can never sound better than the source — a video with compressed 96 kbps audio yields an MP3 of that same underlying quality.

Frequently asked questions

How do I convert MP4 to MP3?

Drop your video into the box above and press Extract audio. The MP3 is created in your browser and downloads when done. MP4, WebM, MOV, MKV and AVI inputs are supported.

Is this tool really free?

Yes — completely free, with no sign-up, no watermarks, and no daily limits. The site is supported by ads, and because conversions run in your browser rather than on our servers, there are no processing costs to pass on to you.

Are my files uploaded to a server?

No. All conversion happens locally in your browser using the Canvas API and WebAssembly. Your files never leave your device, which makes this tool safe for private photos and confidential documents.

Why does the first conversion take a moment to start?

The conversion engine (ffmpeg compiled to WebAssembly, ~31 MB) downloads on first use and is cached by your browser afterwards. This is what makes fully private, in-browser conversion possible.

What audio quality do I get?

A high-quality variable-bitrate MP3 (~190 kbps) — transparent for speech and podcasts, very good for music. The output can never exceed the quality of the audio inside your video.

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