Replace the audio in a video
Swap a video's sound for a song, a voice-over or any recording. The picture stays as it is. It runs on your own computer, so nothing is uploaded.
- Never uploaded
- No size limit
- No watermark
- Free
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Quick answer: To replace the audio in a video, drop the video and the new sound file into the tool at the top of this page, choose what happens if they are different lengths, and press "Replace the sound". The video's own sound is swapped for the new one and the picture is kept. It happens in your browser, so the files are never uploaded. It is free, with no sign-up and no watermark.
Updated
How it works
- Drop the video and the soundTogether or one after the other: the video, and an MP3, M4A, WAV or other sound file.
- Choose how they fitIf the lengths differ, repeat a short sound or cut a long one, add silence, or end with the shorter.
- Replace and downloadYou get an MP4 with the new sound and the same picture.
When the sound and the video are different lengths
- Fit the video: repeat a short sound, cut a long one. A 30-second loop of music runs on until the video ends; a long song is cut off where the video ends.
- Fit the video: silence after a short sound. The sound plays once, then the video carries on in silence.
- End when the shorter one ends. The result is as long as the shorter of the two.
A voice-over or a soundtrack
Record the voice-over on your phone, save it as an audio file and drop it here with the video. For music, use a track you have the right to use: the tool does not check that. To keep the original sound and add a track on top, you need a video editor, because this tool swaps the sound instead of mixing it.
Removing the sound instead
If you only want the video without sound, remove the audio and you are done. To save a video's own sound as a file first, use video to MP3.
Measured, not promised
Timed on 21 Oct 2026 in Chrome on a 2019 Intel MacBook (an older laptop) with a one-minute 720p clip with spoken sound. Newer computers are faster; real files vary. More results.
Why your video never leaves your computer
Your video is processed by your own computer, inside this tab, and never uploaded. That is why there is no size limit and no watermark. How it works.
Questions
Can I keep the original sound and add music?
No. This tool swaps the sound. To mix two sounds together you need a video editor.
Which sound files work?
MP3, M4A, WAV, FLAC, OGG and more.
Does the picture change?
The picture is copied as it is where possible, so it looks the same.
Is my video uploaded?
No. It is processed inside this browser tab and saved straight back to your computer.