Audio Joiner
Merge several audio files into one continuous track, in the order you choose, with optional gaps and loudness matching.
Convert with this tool
or choose a file from your device — it is processed in this tab and never uploaded
Accepted: MP3, WAV, FLAC, M4A/AAC, OGG, Opus — up to 30 files
Files stay on your device. There is no upload, no queue and no watermark, so a conversion works even with the network switched off after the page has loaded.
Supported formats & processing
| Accepted input | MP3, WAV, FLAC, M4A/AAC, OGG, Opus — up to 30 files |
|---|---|
| Produced output | One MP3, WAV, FLAC or M4A containing all the files in order |
| Processing | Web Audio API + canvas + native JavaScript encoders |
| Upload required | No — the file is read locally and never transmitted |
How to use this tool
- Add two or more filesDrag them in together or add them one at a time. The list order is the join order.
- Reorder by removing and re-addingRemove a file from the list and add it again to move it to the end.
- Set the gap between tracksZero for a continuous mix, or one to three seconds for audiobook chapters.
- Leave loudness matching onPeak normalisation keeps the levels consistent across the join.
- Convert and listenThe preview player lets you check the seams before downloading.
About this tool
Joining audio comes up constantly: combining chapters of an audiobook, stitching a live set together, merging several takes into one file, or appending an intro to a recording. The tricky part is not the concatenation, it is making the joins sound natural.
This tool decodes every file to PCM, optionally inserts silence between them, and concatenates sample-accurately so there is no click at the seams. Loudness matching normalises the peak across the whole result, which is what stops one track from being noticeably quieter than its neighbour.
Features
- Sample-accurate concatenation with no clicks at the joins
- Up to 30 files in a single job
- Optional silence between tracks, set to a tenth of a second
- Peak normalisation across the whole result for consistent loudness
- Output as MP3, WAV, FLAC or M4A
- Original files are only read, never modified
Frequently asked questions
What is the join order?
The order shown in the file list. To change it, remove a file and add it again — it will be appended to the end.
Can I join files with different sample rates?
Yes. Everything is decoded and re-rendered at a single rate, so mixed sources combine cleanly. The rate used is reported in the result card.
Why is there a small pause between tracks?
Check the gap setting — a value above zero inserts silence deliberately. MP3 files also carry encoder padding at the start and end of each file, which can add a few milliseconds.
Is there a total length limit?
The limit is device memory. Roughly an hour of stereo audio at 44.1 kHz uses about 600 MB of RAM during processing, which is comfortable on a desktop and borderline on an older phone.