How to Add Music or a Voiceover to a Video

October 27, 2026

Three things people usually want

Adding sound to a video usually means one of three jobs: putting music on a silent clip, laying background music under speech, or recording a voice-over for a video that has no narration. They sound similar, but each calls for a slightly different approach, and getting the volume balance right matters more than the tool you use.

Check you have the right to use the music

Before anything else, make sure you are allowed to use the song. Most commercial music is protected by copyright. On social platforms, a video with unlicensed music can be muted, blocked or removed, and some platforms offer their own libraries of cleared music for this reason. Safer options include music you made, music with a license that allows your use, and royalty-free tracks from services whose terms you have read.

Replace the sound or mix it in

Replace swaps the original sound for the new audio entirely. Use it for a silent clip, for a video where the original sound is noisy, or when you want only music.
Mix keeps the original sound and blends the new audio under it. Use it for background music beneath speech or ambient sound you want to keep.

The add audio to video tool offers both modes, and in mix mode a slider sets the volume of the new track. The result always matches the length of the video: a shorter audio file is not looped, and a longer one is cut off at the end, so choose or prepare a track of about the right length.

Prepare the audio first

Cut the track to length with the audio trimmer, picking a part that ends in a natural place, because there are no fades.
Even out the level with the audio enhancer or adjust it with the audio volume tool if the track is much louder or quieter than your speech.
Make a voice-over with the voice recorder: record in a quiet room, close to the microphone, and save it as an audio file.

Getting the balance right

The most common mistake is music that is too loud, so that speech becomes hard to follow. As a rule, speech should always be easy to understand, and music should sit clearly under it. In mix mode start with the new track at a lower volume than the default and listen. If the original sound is too loud or too quiet, adjust it first with the video volume tool, or remove it completely with the mute video tool before adding the new audio.

Step by step: music under a talking video

Trim the video if needed with the video trimmer.
Prepare the music: trim it to about the video's length and lower its volume.
Open the add audio tool, upload the video and the music, choose mix and set the music level low.
Download, then listen to the whole result, ideally on both headphones and a phone speaker.

Step by step: a voice-over on a silent video

Watch the video once and write a short script that fits its length.
Record the narration with the voice recorder and trim the start and end.
Add it with the replace mode, since the video has no sound to keep.

What this approach does not do

This is a simple swap or blend. There is no fading, no syncing to exact moments and no multi-track editing. For a quick clip that is enough. For something that needs music to change at a specific second, you will want a full editor. Everything here runs in your browser, so your files are never uploaded to a server.

Frequently asked questions

Can I use any song I find online?

Not necessarily. Most commercial music is protected by copyright, and platforms may mute or remove videos that use it without a license. Use music you made, have a license for or that is explicitly free to use.

What happens if the music is longer than the video?

The result matches the length of the video, so the extra music is cut off at the end. A shorter track is not looped, so prepare a track of about the right length.

Which files can I use?

The video can be MP4, MOV or WebM, up to about 200 MB depending on your device, and the new audio can be an ordinary audio file such as an MP3.