Add Music to Video Online Free - Add Audio to Any Clip

By the team at VidHaul

A clip often feels empty without sound. A holiday video, a product demo or a birthday reel comes alive once a song plays behind it. This page lets you add music to video in a few clicks, without installing an editing app and without uploading your files. You can add audio to video of any kind: a song as background music, a clean track in place of wind and traffic noise, or a voice-over you recorded for a screen recording. Choose the video, choose the music or audio, decide whether to replace or mix the original sound, and download. It is a free way to add music to video online, with no watermark and no sign-up, on Android, iPhone or a computer.

How does adding music to a video work?

The tool decodes the sound of your music file into plain audio samples in your browser. With Mix chosen, it also decodes the video’s own sound. Then it builds a new sound track with the Web Audio API that is exactly as long as the video: the music starts at the first second, is multiplied by the Music volume you picked, repeats if Repeat music is ticked, and, when mixing, is added on top of the original sound, which stays at its normal level. This track is encoded as AAC at 128 kbps (Opus for WebM) and packed with the video picture into one file.

A worked example, computed from these settings: Music volume 50% multiplies the music by 0.5, which is 6 dB quieter. For a 60-second clip, the new sound track takes 128 x 60 / 8 = 960 KB, about 1 MB, whatever the length of your song. If a 3-minute song goes on a 45-second video, only the first 45 seconds of the song are used. If a 20-second jingle goes on that video with Repeat ticked, it plays 2.25 times: twice in full and then the first 5 seconds again.

How to add music to a video, step by step

1. Choose the video. Click the box at the top or drag the video onto it. You will see its name, size and a small preview. Use Change file to pick another.
2. Choose the music or audio. Next to Music or audio, press Choose file. MP3, M4A, WAV, OGG and OPUS work, and you can even pick another video to use its sound.
3. Choose the Sound option. Replace original sound is selected first. Switch to Mix with original sound to keep the voices.
4. Set the Music volume. 100% is the default. For background music under speech, 50% or 25% is usually better.
5. Repeat or not. Repeat music to fill the video is ticked. Untick it if the music should play once.
6. Press Start, then Download. A progress bar with Cancel shows how far it is. The file is saved with a name like holiday-music.mp4. To save as MOV, MKV or WebM, open More options before pressing Start.

If you press Start without a music file, the page asks you to choose one first.

Replace the sound or mix it with the music?

• Replace original sound removes the old audio completely, so only your music or voice-over is heard. Use it for wind noise, traffic, a silent screen recording, a slideshow, or any clip where the original sound does not matter.
• Mix with original sound keeps the voices and sounds of the clip and plays the music with them. This is the usual way to add background music to a vlog, a family video or a talk where people speak. If the video has no sound track at all, Mix gives the same result as Replace.

In Mix mode, the original sound always stays at its normal level. Only the music is turned up or down, with Music volume.

How to add background music to a video without losing the voices

The Music volume options are simple percentages, but your ears hear loudness in decibels. This chart shows how much quieter each setting makes the music:

For speech with music behind it, start with Mix and 25%. If the music is too faint, try 50%. 75% and 100% suit clips where the music is the point and nobody is talking. Mixing loud music at 100% with a loud original sound can add up to more than the maximum level, which sounds harsh or distorted; lower the music if that happens.

When the song and the video are different lengths

Your video always keeps its original length. The music is fitted to it, and the table shows every case:

The music always starts at the first second of the video and begins with the first second of the song. Want the chorus instead of the intro? Cut the song first with the MP3 cutter, then use the cut file here. For a soft start and end on the music, cut it with the ringtone maker (Fade in & out, any length) and use that file.

How to add music to video on iPhone

Open this page in Safari or Chrome. Tap the video box and pick the clip from Photos or Files. Then tap Choose file next to Music or audio and pick a song saved in the Files app. Press Start and save the result; it goes to Downloads in the Files app, and from there you can save it to Photos. Songs inside streaming apps are protected and are not available as normal files, so you need a music file you actually have on the phone, such as a track you bought as a download, your own recording or royalty-free music.

How to add audio to video on Android or a computer

On Android, open the page in Chrome and pick both files from your storage: videos are usually in DCIM or Movies, songs in Music or Downloads. On a computer, drag the video onto the box and use Choose file for the music. Phones are slower than laptops, and everything happens in the device’s memory, so very long or very large videos (over about 1.5 GB) are better done on a computer.

How to add recorded audio or a voice-over to a video

Record your voice with your phone’s voice recorder or a computer microphone. Choose the video here, then choose your recording as the music file. Pick Replace for a clean voice-over on a screen recording or slideshow, or Mix at 100% if you want the original sound under your voice. Your recording starts at the very beginning of the video, so leave a short pause at the start of the recording if you need one. Untick Repeat so a short recording does not play twice.

How to add music to YouTube, Instagram or TikTok videos

Make the video with music here, download it and then upload the finished file to the platform like any other video. MP4 is the safest format for all of them. If the video is meant for Reels, Shorts or TikTok and is not vertical yet, use the video cropper or resize video afterwards. Platforms run their own copyright checks: a video with a commercial song you do not have rights to may be muted or blocked. Music you made yourself or royalty-free tracks avoid that.

Add music to video app or online?

Full editing apps can do much more, but for one song on one clip they can be slow to learn, ask you to sign up, or add a watermark unless you pay. This page has nothing to install and adds no watermark. An editing app is still the better choice if you need music to start halfway through the video, several music tracks, or a volume that changes over time; this tool does not do those things.

How accurate is add music to video?

The new sound track is built to the exact length of the video, so the music never makes the video longer or shorter. The Music volume is applied exactly as stated (0.25, 0.5, 0.75 or 1.0 times the music). Limits to know:

• The music always starts at 0 seconds. There is no offset or position setting.
• There is no automatic fade at the end or ducking when people speak; the music level stays the same throughout.
• Repeats join the end of the song straight to its beginning, so a song with a long fade-out or silence at the end will have a gap at each repeat.
• The sound is re-encoded at 128 kbps, which is fine for phones, laptops and social media, but not a lossless copy of the music file.
• When the video is already H.264 and you save as MP4, MOV or MKV, the picture is usually passed through as it is; other videos are re-encoded, which takes longer.
• Videos with unusual codecs may not open in your browser; the page then shows an error.

Why this tool is different

Many online tools that add audio to a video first upload both files to a server. VidHaul combines them in your browser. The music is decoded and mixed with the Web Audio API on your device, the new sound is encoded with the browser’s own encoder (WebCodecs), and the picture is written into the new file there too. Your clips and recordings never leave your phone or computer, and there is no upload wait for big videos.

The controls are few and exact: two sound modes, four volume steps, one repeat switch and four output formats. That makes the result predictable. You can check the claims on this page yourself: the video length shown after processing matches the original, and the Before and After sizes show what changed.

What we measure

After each video the page shows the size before and after, with a Copy summary button. The numbers on this page (decibel values, sound track size, which part of the song is used) are computed from the settings in the tool’s code, not from a lab test, and we say so in each place. We have not published a speed test because speed depends mostly on your device and your video. We do not see your files, and we do not collect statistics about the videos or songs you use, because nothing is uploaded.

Sources

• MDN: GainNode (how the music volume is applied)
• MDN: AudioBufferSourceNode loop (how Repeat music works)
• MDN: OfflineAudioContext (building the new sound track in the browser)
• MDN: WebCodecs API (the browser video and audio encoders)
• YouTube Help: Recommended upload encoding settings (MP4 with AAC audio)

Only use music and videos you own or have the right to use. Platforms may mute or block videos that contain copyrighted songs.