Add audio or music to a video online for free. Replace the original soundtrack or mix a new track in — no upload, no signup, runs entirely in your browser.

Our free online add-audio-to-video tool lets you add a new audio track to any video directly in your browser — with no upload to any server and no watermarks added to the result. Replace the original soundtrack with a music track, mix a voiceover with the existing audio, or attach a soundtrack to a silent video. Everything runs locally using WebAssembly-powered FFmpeg, so both your video and audio files stay completely private on your device.

Whether you’re a content creator adding background music to a vlog, a marketer overlaying narration on a product demo, or a social media user pairing a trending song with a clip, this browser-based tool handles it in seconds with no software installation and no account required.

How to Add Audio to a Video Online for Free

Adding audio to your video takes just a few steps:

Upload your video — Drag and drop an MP4, MOV, AVI, WebM, or MKV file, or click to browse.
Upload your audio — Drop an MP3, WAV, AAC, OGG, FLAC, or M4A file you want to add.
Choose the audio mode — Pick “Replace” to discard the original audio, or “Mix” to combine both tracks.
Add audio and download — Click Add Audio to Video and save the result directly to your device.

Key Features

Free and Unlimited — Add audio to as many videos as you need with no daily limits or subscription fees.
No Upload Required — All processing happens locally in your browser. Your files never touch a remote server.
Replace or Mix — Overwrite the original soundtrack entirely, or mix the new audio with the existing track.
Trim to Video Length — Optionally stop the output as soon as the video ends, so a long audio track doesn’t add a black-screen tail.
Multiple Audio Formats — Accepts MP3, WAV, AAC, OGG, FLAC, and M4A audio inputs.
Multiple Video Formats — Works with MP4, MOV, AVI, WebM, and MKV input files.
No Watermarks — The output video is completely clean with no added branding.
Mobile-Friendly — Works in Safari on iOS and Chrome on Android.

Replace vs. Mix Mode

Mode	What it does	Best for
Replace	Discards the original audio and uses only the new track	Adding music to a silent video, swapping an unwanted soundtrack
Mix	Combines the original audio with the new track	Adding background music while keeping speech or narration

Note: Mix mode requires the video to already have an audio track. If your video is silent, use Replace mode instead.

Why Choose Our Free Add-Audio Tool?

True local processing — No uploads, no server-side handling. Both your video and audio files stay on your machine.
No registration — No account, no email, no payment required.
No watermarks — The result is yours, clean and unbranded.
Fast and private — Because nothing is uploaded, processing starts instantly and your media stays private.

Common Use Cases

Background music for vlogs — Add a license-free music track to a vlog before publishing to YouTube or TikTok
Voiceover narration — Record a narration track and pair it with a product demo or tutorial video
Social media clips — Pair a trending song with a short clip for Instagram Reels, TikTok, or YouTube Shorts
Silent video soundtracks — Add a soundtrack to a silent video recorded with a DSLR or action camera
Presentation audio — Attach a recorded commentary to a slide-recording video for async presentations
Replacing unwanted audio — Swap an audio track with distracting background noise for a clean music bed

Frequently Asked Questions

Can I add music to a video without uploading it?

Yes — our tool runs entirely in your browser using WebAssembly. You select a video and an audio file from your device, and all processing happens locally. Nothing is ever uploaded to a server.

What audio formats can I add?

You can upload MP3, WAV, AAC, OGG, FLAC, and M4A audio files. The audio is re-encoded to AAC inside the output video for broad compatibility.

Will the original audio be removed?

Only if you choose “Replace” mode. In “Mix” mode, the original audio is combined with the new track so both play at the same time.

What does “Trim audio to video length” do?

When enabled, the output stops as soon as the video ends (using FFmpeg’s -shortest flag). This prevents a long audio track from producing a black-screen tail after the video finishes.

Does adding audio re-encode the video?

No — the video stream is copied without re-encoding (-c:v copy), so video quality is preserved and processing is fast. Only the audio track is re-encoded to AAC.

Extract Audio — Pull the audio track out of a video as a separate file
Mute Video — Remove the audio track from a video entirely
Video Volume — Adjust the volume level of an existing audio track
Video Trimmer — Trim your video before adding a new audio track

Free Online Add Audio to Video Tool