Add Audio to Video Free — Replace Sound Track Online
Add music or audio to video online for free. Replace the sound track of any MP4, MOV, AVI video. Private browser processing.
Access and pricing
Supported tools include 5 free on-device uses per day, shared across eligible tools. On compatible devices, guest access needs no sign-in. Signed-in users also get 5 daily eligible on-device uses. AI and cloud processing use credits separately.
New accounts can claim 20 welcome credits once. Eligible offers in MiOffice can earn up to 80 reward credits; offer conditions apply.
Starter costs $6.99/month and includes 250 credits at each paid renewal plus unlimited eligible local processing. Unused credits roll over. The $2.99 Day Pass covers 24 hours of eligible local processing; AI and cloud credits are separate.
Compare tools using a representative file and inspect the export. Check supported formats, device compatibility, processing location and the displayed cost before starting. This article is published by MiOffice; consider its recommendations with that affiliation in mind.
Access and pricing updated October 30, 2026. This editorial update does not indicate a new test run.
Adding custom audio to video is essential for content creators. Replace noisy original audio with clean voiceover, add background music to silent screen recordings, or swap the soundtrack entirely. With 5,700 monthly searches, this is a frequent need that usually requires downloading editing software.
MiOffice adds audio to video in your browser using FFmpeg WebAssembly. Upload a video and an audio file, click process, and download. No software install, no server upload.
How to Add Audio to Video
- 1
Open the Add Audio Tool
Go to the add audio to video tool.
- 2
Upload Video + Audio
Upload your video file (MP4, MOV, AVI, WebM, MKV) and your audio file (MP3, WAV, M4A, AAC, OGG, FLAC).
- 3
Download Combined Video
Click process. Your video with the new audio track downloads as MP4.
Common Workflows
| Scenario | Video Source | Audio Source |
|---|---|---|
| Tutorial voiceover | Screen recording (muted) | Recorded narration (MP3) |
| Music video | Filmed footage | Music track (MP3/WAV) |
| Social media reel | B-roll clips | Trending audio (M4A) |
| Presentation | Slide recording | Background music (MP3) |
Related Workflow
- --Want to remove audio first? Use Mute Video to strip the original audio.
- --Need to extract audio from another video? Use Video to MP3.
- --Trim your audio to the right length with MP3 Cutter.
- --Normalize volume levels with Audio Normalizer.
Privacy
Both your video and audio files are processed locally in your browser. No files are uploaded to any server. FFmpeg WebAssembly handles the entire operation on your device.
Process Your Video Now
MiOffice AI is an AI-powered digital workspace studio. Create, edit, convert, compress, collaborate, and share — video, audio, images, documents, scanning, notes, screen sharing, and file transfer. the full MiOffice catalog, all in one place.
Frequently Asked Questions
How do I add audio to a video?
What if the audio is longer than the video?
What if the audio is shorter than the video?
Can I keep the original audio and add music on top?
Jay Padimala
CEO & Founder
Jay Padimala is CEO and Founder of MiOffice, a product of JSVV SOLS LLC.
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