Add Audio to Video
Upload a video and an audio file, then merge them together. Replace the original audio or mix them. No install, no signup.
What this page helps with
If you want to add music or a voiceover to a video without Premiere or CapCut, replace the soundtrack on a video, mute a video and add new audio, add royalty-free music to a reel to avoid copyright or merge an audio file with a video file online, use this tool above. No login, no app install, no watermark.
Replace or mix audio on any video without installing editing software. Upload your video and audio files, merge them in your browser, and download the result as MP4. Swap background music, add voiceover narration, overlay sound effects, or mute the original audio. Supports MP4, MOV, WebM, MP3, WAV, AAC, and more. Free, fast, no signup required.
Click to upload or drag and drop
Max 500 MB
Click to upload or drag and drop
Max 500 MB
How to Add Audio to a Video
- 1Upload your video file (MP4, MOV, WebM, up to 500 MB).
- 2Upload your audio file (MP3, WAV, AAC, M4A).
- 3Choose whether to replace the original audio or mix both together.
- 4Click “Merge Audio & Video” and wait for processing.
- 5Preview the result and download your new video.
Need a video to work with? Download one with our Reel Downloader. Need the audio from a reel? Try Audio Extractor.
People Also Ask
Frequently Asked Questions
What video formats are supported?
We support MP4, MOV, WebM, AVI, and MKV video files up to 500 MB.
What audio formats are supported?
We support MP3, WAV, AAC, M4A, OGG, and WebM audio files.
What's the difference between Replace and Mix mode?
Replace mode removes the original audio from the video and adds the new audio. Mix mode overlays the new audio on top of the original, so you hear both.
What if my audio is longer than the video?
The output will match the duration of the shorter file. Extra audio will be trimmed automatically.
Is there a file size limit?
Yes, both video and audio files can be up to 500 MB each.
How long does processing take?
It depends on the file size. Most short clips are processed in under 30 seconds. Larger files may take a few minutes.
How do I replace the music on a video without Premiere Pro or CapCut?
Upload your video above, upload your new audio track, select 'Replace' mode, and click merge. ReelTools handles the audio swap entirely in your browser — no desktop editing software needed.
Can I add a voiceover to a downloaded reel?
Yes. Download the reel using our reel downloader, record your voiceover as an MP3 or WAV, then upload both files here. Use 'Replace' mode for voice-only or 'Mix' mode to keep the original audio underneath.
Can I swap reel audio with royalty-free music to avoid copyright?
Absolutely. Download the reel, then use this tool to replace its audio with royalty-free music. The result is a clean video with your chosen soundtrack, safe to post without copyright strikes.
How do I mute a video and add a new soundtrack?
Upload your video and a silent audio file (or any new track), then select 'Replace' mode. This strips the original audio and adds your new file. To fully mute without adding new audio, use Replace mode with a short silent MP3.
Does this work on mobile browsers?
Yes. The tool works in Safari, Chrome, Firefox, and any other mobile browser on iPhone or Android. Upload, merge, and download directly on your phone.
How do I put a voiceover on a video I already have?
Upload your video and your voiceover as an MP3 or WAV file above. Choose Replace to swap the original audio, or Mix to keep both. No Premiere or CapCut needed.
Can I mix two audio tracks with a video (keep original + add new)?
Yes. Select Mix mode when merging. The new audio is overlaid on the original so you hear both. Use Replace mode if you want only the new track.
How do I merge an audio file with a video file online?
Upload the video and the audio file above, choose Replace or Mix, and click Merge Audio & Video. The result downloads as MP4 — no software to install.