Audio Joiner and Merger

Audio Joiner and Merger

Join several audio files into one MP3 or WAV in your browser with drag to reorder and crossfade.

Drop audio files here or choose files

MP3, WAV, OGG, M4A, FLAC and more. Nothing is uploaded.

No files yet. Add two or more clips and they are joined in the order shown. Files are read on this device and never uploaded, so this works offline too. Up to about 2 hours in total, limited by your device's memory. Volumes are kept as they are (no normalization).

0 to 10. Replaces the gap.

How it works

  1. Add your clips. Drop audio files on the page or pick them. Each one is read on your device to show its length; nothing is uploaded.
  2. Set the order. Drag the rows or use the arrow buttons, then choose a gap or crossfade, MP3 or WAV, and a file name.
  3. Join and save. Press Join. The clips are decoded, resampled to the first file's rate, stitched and encoded in your browser. Listen, then download.

Questions, answered

Are my audio files uploaded anywhere?

No. Audio Joiner and Merger runs entirely in your browser. Your files are decoded and joined in memory on your device and never sent to a server. You can disconnect from the internet and it keeps working.

Which formats can I join?

Anything your browser can decode: MP3, WAV, OGG, Opus, and usually M4A, AAC and FLAC. Some M4A or FLAC files will not open in every browser; those rows are marked and skipped. Files may have different sample rates and channel counts: everything is converted to the first file's rate, and mono clips play on both channels.

How do the gap and crossfade work?

A gap inserts silence between clips. A crossfade overlaps the end of one clip with the start of the next and fades between them, so a 2 second crossfade makes the result about 2 seconds shorter per join. The volume of each clip is kept as it is: there is no loudness normalization, so very quiet and very loud clips stay that way.

Is there a size limit?

Only your device's memory. Joined audio is held uncompressed while it is built, so about 2 hours in total is a sensible ceiling; phones may manage less. There are no accounts, quotas or watermarks.

Is it really free? Does it work offline?

Yes and yes. It is open source under the MIT license, with no account, no limits and no ads. After your first visit a service worker caches the page so it loads without a connection, and you can install it from your browser's menu. If it saves you a paid app, you can say thanks on Ko-fi.

Was this written by AI?

Yes. Audio Joiner and Merger was generated by Claude Code from a written specification inside an automated pipeline, with a test suite that runs in a real browser. The full source is on GitHub, so you can read every line before you trust it with your files.

Built by one person, given away for free

Audio Joiner and Merger is a free alternative to paid tools like Audio Joiner at 123apps. If it earns a place in your bookmarks, a coffee keeps the updates coming.

☕ Support Or on Ko-fi