MP4 to MP3 Converter
Convert MP4 to MP3 on your device. Extract audio with selectable MP3 bitrate. Preview and download the result without uploading your video.
Up to 100 MB. The conversion engine downloads on first use (~31 MB).
How to convert MP4 to MP3
Choose or drop a MP4 file, select an audio bitrate and click Convert. The page downloads its conversion engine on first use, shows progress and then processes the file on your device. Preview the result and download it.
The input is limited to 100 MB. Conversion may take longer than the media duration, particularly on phones. Cancel stops the engine and frees its working memory; you can select a smaller file or retry afterward.
What the conversion changes
MP4 is a container that can hold video and audio. This tool extracts the first audio track and encodes it as MP3 at 128, 192 or 320 kbps. The video track is omitted. If the input has no audio track, conversion fails with a clear error.
A higher output bitrate cannot restore quality already lost in the original audio. MP3 is lossy, and re-encoding may increase the file size without improving the sound. This page does not download media from a URL.
Engine download, privacy and failures
The page uses the single-threaded FFmpeg WebAssembly engine. Its version-pinned JavaScript and WebAssembly files are downloaded from jsDelivr when conversion starts. Your selected media stays on this device and is not uploaded to the CDN.
Processing needs memory for the compressed input, decoded media and output. Browser memory pressure, unsupported codecs or a missing required track can cause failure even for a file below 100 MB. A conversion is stopped after five minutes; use a smaller clip or a desktop encoder for larger jobs.
Questions & answers
Will renaming the file extension work?
No. Renaming does not change the encoded streams. This tool performs an actual conversion and checks the encoder exit status before offering a download.
Why does the first conversion load slowly?
The conversion engine is about 31 MB and is loaded only when needed. The status displays download progress; browser caching can help subsequent visits.
Can I cancel or convert offline?
You can cancel an active conversion. The engine must be downloaded before processing; this page does not promise offline availability across new visits.