MP4 to MP3 Converter
Extract the audio you need from a local video, choose its time range, and save an MP3 without an upload.
- Runs in your browser — files never leave your device
- Instant — no waiting, no queue
Drop a video here, click to choose, or paste
MP4, MOV, M4V, or WebM · browser-playable files with an audio track
Your video is decoded and encoded in this browser. It is never uploaded.
How to use
- Drop a video file, click to choose it, or paste a copied video file.
- Wait for the browser to read its audio track and show the actual video length.
- Enter the Start and End times for the part you want, then choose 128, 192, or 320 kbps.
- Select Extract MP3 or press E, preview the result, and download it to your device.
What “MP4 to MP3” changes
MP4 is a container that commonly holds video plus an AAC audio track; MP3 is a separate, lossy audio format. This tool decodes the selected audio in the browser and encodes a new MP3, so the video image is not in the download and the source video is not modified. Choose 128 kbps for speech-led lectures and meetings, 192 kbps as a practical music and general-video default, or 320 kbps when file size matters less. The approximate CBR payload is bitrate × seconds ÷ 8, which is why a 60-second 128 kbps MP3 is about 960 KB before small encoder overhead.
Extract only the useful part
Set Start and End in seconds before extracting to make a short MP3 from a longer class, interview, screen recording, or personal video. The selected PCM samples are copied to an encoder worker, so the page can keep responding while it creates the file. Start at 0 and leave End at the displayed duration to extract the whole audio track. Keep the original video until you have played the MP3 and confirmed that the intended track and time range are correct.
Which videos work in a browser
The input must be a local file that the current browser can decode and that contains an audio track. MP4, M4V, MOV and WebM are offered as common file choices, but the codecs inside a container determine whether the browser can read it. Encrypted streaming downloads and videos without sound cannot be converted. This focused tool does not fetch YouTube or other video URLs: use only files you own or are allowed to convert.
Frequently asked questions
Does this MP4 to MP3 converter upload my video?
No. The selected video is decoded, sliced and MP3-encoded in the current browser on your device. Betterbit does not receive the video or the resulting MP3, and the completed file is downloaded directly by the browser.
Which MP3 bitrate should I choose for a video?
Choose 128 kbps for spoken lectures, meetings and podcasts, 192 kbps for a balanced music or general-video file, and 320 kbps when you prefer a larger MP3. At constant bitrate, 60 seconds at 128 kbps is about 960 KB and 60 seconds at 320 kbps is about 2.4 MB before small encoder overhead.
Can I extract only part of a video as MP3?
Yes. Set the Start and End time in seconds before selecting Extract MP3. For example, Start 30 and End 90 creates an MP3 from the 60-second interval between those times instead of the full video.
Why can a video fail even though its file extension is MP4?
MP4 is a container, not a guarantee of its video or audio codec. A browser must be able to decode the audio inside the file, and the file must contain an audio track. Protected streaming downloads and silent clips cannot be read as MP3 audio by this tool.
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Updated 2026-10-27