Add Background Music to Video Online Free
Add background music or audio to a video online for free. Place music, voiceover, or sound effects on the timeline in your browser. No upload, no watermark.
Short answer: Yes—use NanoPix Add Audio to put music on a video online for free. Add background tracks, voiceovers, or sound effects, place each clip on the video timeline, and export. No upload to any server, no watermark, completely free.
How to add background music in 3 steps
- Open Add Audio and import your video file (MP4, MOV, MKV, WebM, AVI supported).
- Import your audio file (MP3, AAC, WAV, M4A, FLAC supported).
- Trim the audio source range, position the clip on the video timeline, choose whether to keep the video's original sound, and click Export.
The waveform shows the source range used by each audio clip, while the program timeline shows where it plays in the video. You can add up to 12 clips and preview a selected range before export.
Original audio options
- Leave Keep original video audio off to replace the video's soundtrack with the added clips.
- Turn it on to retain the original soundtrack and mix it with the added clips.
- Preview the result before export to confirm that the clip timing matches the picture.
Timing controls
- Program in/out — choose where the clip starts and ends on the video timeline
- Source in/out — trim the portion of the imported audio file that is used
- Timeline handles — drag the clip to adjust its placement and duration visually
- Multiple clips — add music, narration, and effects as separate clips and position each independently
Supported file formats
| Media type | Supported formats |
|---|---|
| Video | MP4, MOV, MKV, WebM, AVI |
| Audio | MP3, AAC, WAV, FLAC, M4A |
Practical use cases
- Social media videos — add trending background music for engagement
- Presentations — enhance screen recordings with gentle background tracks
- Home videos — overlay sentimental music for atmosphere
- Fitness videos — add energetic tracks to workout recordings
- Product demos — background music makes demos feel more polished
Related tools
- Trim video — cut your video to the right length before adding audio
- Audio Merge — combine multiple audio tracks into one before overlaying
- Overlay PiP — add picture-in-picture along with audio
FAQ
Can I replace the original video audio entirely?
Yes. Leave Keep original video audio unchecked. The output will contain the added audio clips instead of the video's original soundtrack.
Will adding background music increase the file size?
Yes, because the video must be re-encoded with the new audio track. The increase depends on the audio bitrate and duration—typically 1–5 MB extra for a standard-length video.
Can I add multiple audio tracks at once?
Yes. You can add up to 12 audio clips, trim each source range, and place every clip independently on the video timeline.
Can I fade the background music in and out?
Not currently. Trim and position the audio clip in NanoPix, or apply fades in an audio editor before importing it.
Is it safe to add audio to videos online?
Yes. All processing runs locally in your browser. No files are uploaded to any server.
Do I need an account to use the audio mixer?
No. NanoPix is free and requires no registration. All features are available immediately.