Free Online Add Audio to Video
Replace the audio track in any video, or add music to a silent clip. Upload your video and an audio file, choose how to handle length differences, and download. Everything runs in your browser. Your files never leave your device.
Drop your video here or click to browse
MP4, WebM, MOV, AVI, MKVHow to add or replace audio in a video
Frequently asked questions
Will the original audio be removed?
Yes — the original audio track is completely replaced by the new one. If you want to mix the new audio with the original (rather than replace it), you would need a full video editor. This tool is designed for replacement, not mixing.
What if my audio is longer than the video?
The audio is automatically trimmed to match the video length. Only the portion of the audio that fits within the video duration will be used. If you want to use a specific section of a longer audio file, trim it first using a free audio editor before uploading here.
What if my audio is shorter than the video?
You have three options: Loop audio repeats the audio track seamlessly until the video ends — ideal for background music. Trim video shortens the video to match the audio length. End with silence plays the audio once and leaves the remainder of the video silent.
Is my video or audio uploaded to a server?
No — everything runs locally in your browser using WebAssembly (FFmpeg.wasm). Neither your video nor your audio ever leaves your device. No data is stored or transmitted anywhere.
Can I add audio to a video that has no sound?
Yes — this tool works equally well on silent videos. Upload the video and an audio file and it will be combined. There’s no requirement for the original video to have an audio track.
Which browsers are supported?
The Add Audio to Video tool works in any modern browser supporting WebAssembly and SharedArrayBuffer: Chrome 92+, Edge 92+, Firefox 90+, and Safari 15.2+.
