About this tool
Combine a video file with a separate audio track into a single MP4 locally in your browser for free. Stream-copy video for fast export or optionally re-encode; no software install and no file uploads.
Video & Audio Merger: Combine Separate Video and Audio Files Locally into MP4
Questions & answers
How do I use Merge video & audio?
Select a video and a separate audio file. The merged result ends with the shorter input; video re-encoding is optional.
What limits should I know about?
Speed and compatibility depend on browser, codecs and memory. Prefer short inputs and save results before closing the page.
Where do my files and data go?
Your media is processed in this browser, not uploaded to this site. Save results before refreshing or closing.