How to merge audio files into one track
Merging audio means joining several files end to end so they play as one continuous track. It is the everyday job behind stitching podcast segments, combining voice notes, or assembling a set — and it takes seconds in the browser.
What does merging audio actually do?
Merging (also called concatenating) places files one after another on a single timeline: file A plays, then file B begins where A ended, then C, and so on. This is different from mixing, which layers tracks *on top of* each other to play at the same time. If you want a voiceover over background music, that is mixing; if you want part 1 followed by part 2, that is merging — and merging is what this guide covers.
When do you need to merge audio?
- Podcasts — stitch an intro, the interview, and an outro into one episode.
- Voice notes — combine several recordings into a single shareable file.
- Music — join tracks into a continuous mix or a single long file for a playlist.
- Audiobooks / lectures — assemble chapters or sessions recorded separately.
- Language learning — concatenate phrase clips into one practice track.
How to merge audio files, step by step
- Open the merge audio tool. On first use it loads the ~10 MB engine once, then reuses it.
- Add your files by dropping them in. Order matters — they play top to bottom, so add them in sequence.
- Remove or re-add any file if the order is wrong.
- Click merge. The tool joins them and re-encodes to a single MP3, then offers it for download.
Can you merge different formats together?
Yes. Because each file is decoded to raw audio before being joined, you can merge an MP3, a WAV and an M4A into one track without converting them first. The output is a single MP3. If your files have different sample rates or channel counts, the tool resamples them to match so there are no clicks or speed changes at the joins.
| You want to… | Use |
|---|---|
| Play files one after another | Merge (this guide) |
| Layer music under a voiceover | A mixing/DAW app (not a merge) |
| Cut one file into pieces | Split audio |
| Keep only a section of a file | Trim audio |
How do you add a gap between clips?
A straight merge butts each file directly against the next with no silence. If you want a breath between segments — common between podcast chapters — trim a short silent clip and insert it, or add a moment of silence to the end of each part with an audio editor before merging. For most spoken-word joins, a clean cut sounds natural because the recordings already end on a pause.
Is anything uploaded when I merge?
No. The merge happens entirely in your browser using ffmpeg compiled to WebAssembly. Your recordings — which are often private interviews or personal notes — never leave your device. Open DevTools → Network while you merge and you will see no upload request. You can also disconnect from the internet after the page loads and it keeps working.
Frequently asked questions
How many files can I merge at once?
As many as your device’s memory allows. There is no server-imposed limit because there is no server. Very large or numerous files use more memory, so on a phone keep the total reasonable.
Will merging reduce the quality?
The output is re-encoded to MP3, so there is one round of compression. At 192 kbps or higher the difference is very hard to hear. If you need lossless joins, work with WAV inputs and a lossless editor.
Can I reorder files after adding them?
Remove a file and add it again in the right place. Files always merge in the order they appear in the list, top to bottom.
Do the files need to be the same format?
No. You can mix MP3, WAV, M4A and others. They are decoded and joined into one MP3 regardless of the input formats.
Can I merge audio from videos?
Extract each video’s audio first with video to MP3, then merge the resulting MP3s.
What if there is a click at the join?
Clicks usually come from clips that were cut mid-waveform. Trim each clip to end on a zero-crossing or a natural pause, or add a tiny fade with fade in/out before merging.