How to Add Music to a Video in Your Browser, Free

To add music to a video, load the video and the music file into an add-audio tool, choose whether the song replaces the original sound or mixes over it, set the music volume as a percentage, keep MP4 as the output and click Add audio. The picture is copied without re-encoding, so quality stays the same and the export is quick.

Music changes how a clip feels more than any filter. A silent product demo looks unfinished, a clip with wind noise sounds amateur, and a tutorial with a quiet bed of music under the voice holds attention longer. The good news is that you do not need a timeline editor for any of this. If all you want is one track under one video, a browser tool does the job in a minute.

Free toolAdd Audio to VideoAdd music or voiceovers to your video, adjust track volume, or replace existing sound completely in your browser without uploading your files to any server.Open the tool

Decide first: replace or mix?

Before you open any tool, answer one question: should anyone still hear the original sound?

• Replace throws away the original audio and uses only your music file. Pick it for clips with wind, traffic or background chatter, product b-roll, time-lapses and slideshows made from photos.
• Mix keeps the original audio and lays the music underneath. Pick it for talking-head videos, tutorials, unboxings with commentary and anything where the voice carries information.

How to add music to a video step by step

The steps use the Add Audio to Video tool, which processes both files inside your browser.

1. Open the tool page. The first time, your browser downloads a video engine of about 30 MB once; afterwards it loads from cache and even works offline.
2. Drop your video into the first area. MP4, WebM, MOV, MKV, AVI, FLV and 3GP files are accepted.
3. Drop the music into the Audio to add area. MP3, WAV, M4A, AAC, OGG, FLAC and Opus all work.
4. Under How to add it, choose Replace the existing audio or Mix over the existing audio.
5. Type a value in Volume (%). This controls the added music: 100 leaves it unchanged, 50 halves it, 200 doubles it.
6. Keep Output format on MP4 when your source is an MP4 or an iPhone MOV. Because the picture is copied rather than re-encoded, matching a common container avoids errors.
7. Click Add audio, wait for the progress bar, preview the result and download it.

Free toolAdd Audio to VideoAdd music or voiceovers to your video, adjust track volume, or replace existing sound completely in your browser without uploading your files to any server.Open the tool

Recommended music volume for each situation

The Volume field only affects the music you add, so the right number depends on the mode and on what else is in the soundtrack.

Situation	Mode	Suggested music volume	Why
Silent slideshow or b-roll	Replace	100 percent	Nothing to compete with
Noisy outdoor footage	Replace	80 to 100 percent	Removes the noise entirely
Voiceover or talking head	Mix	20 to 30 percent	Speech stays clear
Unboxing with light commentary	Mix	30 to 50 percent	Music is felt, voice still leads
Music file recorded too quietly	Replace	120 to 150 percent	Lifts a low-level recording

These are starting points, not rules. Loudness differs a lot between songs, so always listen to the preview on both a phone speaker and headphones.

What happens to your files

Knowing what the tool does explains the results you get. The video stream is copied bit for bit into the new file, which is why the export is fast and the picture looks identical to the original. The soundtrack is encoded as AAC at 192 kbps, the audio format that MP4 players expect.

The length of the output follows the shorter stream. In Replace mode, if your song is 40 seconds and the video is 60 seconds, the result is 40 seconds long. If the song is longer than the video, the music is simply cut when the picture ends. In Mix mode the timing follows the original soundtrack, so the video keeps its full length. If the video has no audio track at all, Mix falls back to Replace automatically.

Mixing two sources can also change the overall level, so the original voice may sound a little quieter than before. Preview the file and adjust the music volume until the balance feels right.

Prepare the music before you add it

A few minutes of preparation makes the difference between an obviously pasted-on track and something that sounds edited.

• Trim the song to the part you want. Most tracks have a slow intro. Cut straight to the section that matches the energy of the video with an audio cutter.
• Add a fade-out. The music stops abruptly when the video ends. A two to three second fade on the music file makes the ending feel intentional.
• Match the length. For Replace mode, make sure the track is at least as long as the clip.
• Check the license. Royalty-free libraries and tracks licensed for commercial use are the safe choice for product and ad videos.

If the video itself will not load, the container or codec is usually the cause. Screen recordings often arrive as WebM; the guide to converting WebM to MP4 locally in the browser or the WebM to MP4 Converter fixes that first. Footage from game capture and some cameras comes as MKV, covered in the MKV to MP4 conversion guide. For every other format, the MP4 Video Converter produces H.264 files that work well here, and our guide on how to convert video files for any device or platform explains why that combination is the safest.

Finished file too large for a marketplace or email? Run it through the Video Compressor with a target size. Check the current upload limits on Shopify, Etsy, eBay or Amazon, since they differ and change over time.

Common mistakes

• Using Mix on noisy footage, which keeps the wind or traffic under your music; switch to Replace when the original sound adds nothing.
• Leaving music at 100 percent under a voiceover, which buries the speech on phone speakers; set the volume to 20 to 30 percent and listen again.
• Adding a song shorter than the video in Replace mode, which cuts the end of the clip; loop or extend the track first so it covers the full length.
• Choosing WebM output for an MP4 source, which can fail because the H.264 picture is copied, not converted; keep MP4 output, or convert the video first if you really need WebM.
• Skipping the fade-out, which makes the music stop mid-bar at the last frame; fade the final seconds of the music file before adding it.
• Using commercial songs without a license, which gets videos muted or blocked on many platforms; pick royalty-free or properly licensed tracks.

Frequently asked questions

Will adding music reduce the quality of my video? No, the picture quality stays exactly the same. The video stream is copied into the new file without re-encoding; only the soundtrack is encoded, as AAC audio at 192 kbps.

What volume should background music have under a voice? Start with the music at 20 to 30 percent in Mix mode. Speech stays clear at that level on phone speakers; raise it only if the music disappears completely on headphones.

What happens if the song is shorter than the video? In Replace mode the output ends when the song ends, so the end of the video is cut. Use a track at least as long as the clip, or join two copies of the song with an audio joiner before adding it.

Can I use any popular song in my product video? No, not without a license. Commercial songs are protected by copyright, and platforms can mute, block or claim videos that use them, so choose royalty-free music or tracks whose license covers commercial use.

Put the soundtrack on in a minute

Adding music to a video comes down to one decision and one number: replace or mix, and how loud the music should be. Prepare the track so it is long enough and fades out, keep the output as MP4, and let the tool copy your picture untouched. Open Add Audio to Video, drop in both files and download the finished clip without uploading anything.