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Audio Joiner

  • Free, no sign-up
  • Runs in your browser
  • Works on mobile
How it works. Add two or more audio files, put them in the order you want, choose how to join them, and save one file. The files stay on your device.

How to join audio files

  1. Drop two or more audio files on the box above. You can add more later.
  2. Use the up and down arrows to set the order. The cross removes a file.
  3. Under Between files, choose Join directly, Add silence or Crossfade.
  4. Pick a format and press the join button.
  5. Download the combined file.

Between files

ChoiceWhat it does
Join directlyThe next file starts the moment the last one ends.
Add silenceInserts 0.5, 1, 2 or 3 seconds of silence between files.
CrossfadeThe end of one file fades out while the next fades in. The total gets shorter by the overlap.

Tips

  • Files with different sample rates or channel counts are matched for you.
  • For music mixes a 1 to 3 second crossfade sounds smooth. For podcast parts, a short silence works better.
  • Check the total length shown above the join button before you save.
  • Save as WAV if you will edit the result again.

Limits

All files are decoded in memory at once, so joining many long recordings needs a lot of memory. The tool does not match the loudness of different files. We tested desktop Chrome only.

Privacy

Your audio never leaves your device. There is no upload, no account and no watermark.

FAQ

How do I merge MP3 files into one?

Drop all the MP3 files, order them with the arrows, choose Join directly, pick MP3 as the format, and press join.

Can I join different formats?

Yes. You can mix MP3, WAV, M4A and other formats your browser can read. The output uses the format you choose.

Will there be a gap between files?

Not with Join directly. In our test, a 3 second and a 2 second file joined to exactly 5 seconds.

What does crossfade do to the length?

The files overlap, so the result is shorter. A 3 second and a 2 second file with a 1 second crossfade came out at 4 seconds.

Can I change the order after adding files?

Yes. Use the up and down arrows next to each file. Your format and gap settings stay as they are.

Are my files uploaded?

No. Everything runs in your browser.

About this tool. Built and tested by the ToolsRiver team, November 2026. We tested it in desktop Chrome with generated WAV files. Joining 3 and 2 second files gave 5, 6 (with 1 second of silence) and 4 seconds (with a 1 second crossfade). We also joined a 44.1 kHz file with a 22.05 kHz file and saved the result as OGG. It runs on Mediabunny by Vanilagy (Mozilla Public License 2.0), with its MP3 encoder add-on, loaded from the jsDelivr CDN. Found a file it handles badly? Tell us on the Contact page. More audio tools: Audio Converter, Audio Cutter, Voice Recorder.

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