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Audio Cutter & Joiner

Trim, split, reorder, preview, and join multiple audio clips locally into MP3, M4A/AAC, or WAV.

View on GitHub
Local processing
About your filesFiles and content selected in this tool are processed in your browser and are not uploaded to a Browser Kitty backend.
Operation demo See the basic workflow in a short video.

About this tool

Audio Cutter & Joiner is a browser tool for keeping the useful parts of multiple audio files, arranging them in the order you want, and exporting the result as one audio file. Adjust each clip's start and end points on a waveform, split at the current playhead, remove unwanted clips, and reorder them by drag-and-drop or move buttons.

Before exporting, you can preview the complete sequence or listen only around the boundary between adjacent clips. Selected audio, waveform analysis, editing, preview, and export are processed in the browser and the source audio is not uploaded to Browser Kitty.

Good for

  • Remove silence or unwanted material from the beginning or end of a recording
  • Keep selected parts from several audio clips and join them into one file
  • Reorder lecture, interview, or voice-note clips before saving
  • Edit audio without uploading it to an online editing service

What it can do

Key capabilities available in this tool.

How to use

  1. Choose one or more audio files. On desktop, you can also add files by drag and drop.
  2. Select a clip and adjust the usable start and end range with the waveform handles or time fields.
  3. If needed, move the playhead and split the clip, then remove any unwanted pieces.
  4. Reorder clips into the final sequence by dragging them or using the move buttons.
  5. Preview the complete sequence or listen around clip boundaries before exporting.
  6. Open Export, choose MP3 / WAV or M4A/AAC when available, set the filename and bitrate as needed, then save the result.

Supported

  • Input: MP3, M4A/AAC, WAV, OGG, Opus, WebM, and other formats supported by the browser/OS audio decoder.
  • Editing: waveform trimming, time fields, split at playhead, delete, reorder, and one-level Undo for trim, split, delete, and reorder operations.
  • Preview: play the selected clip, preview the final sequence continuously, or audition the boundary between adjacent clips.
  • Output: MP3 at 128 / 192 / 256 / 320 kbps and WAV PCM 16-bit. M4A/AAC is available when the browser supports WebCodecs AAC encoding. Output is 44.1 kHz stereo.

Limitations and notes

  • Readable audio codecs depend on the browser and operating system. A familiar file extension does not guarantee that its internal codec can be decoded.
  • M4A/AAC export is available only when the browser supports WebCodecs AAC encoding. Use MP3 or WAV when it is unavailable.
  • Exports are converted to 44.1 kHz stereo regardless of the source sample rate or channel layout.
  • Long or high-bitrate audio can use substantial memory during waveform analysis and export.
  • This is not a multitrack DAW: layered mixing, recording, effects, and metadata editing are out of scope. Undo covers only the most recent supported operation.

Frequently asked questions

Are my audio files uploaded to a server?

No. Loading, waveform analysis, trimming, splitting, reordering, preview, and export run in the browser. The runtime CSP also uses connect-src 'none', with no runtime CDN, analytics, or telemetry.

Can I join several audio files into one?

Yes. Add multiple files, trim each one as needed, arrange the clips in the final order, and export them as one audio file.

Why is M4A export unavailable in my browser?

M4A/AAC export requires browser support for WebCodecs AAC encoding. When it is unavailable, the app disables M4A and directs you to MP3 or WAV instead.

Can I layer and mix audio tracks?

No. This tool arranges clips sequentially on one timeline. Simultaneous multitrack playback, mixing, and effects are out of scope.

Offline version and source code

The root-level audio-cutter-joiner.html is a self-contained single HTML file with the required code, including the MP3 encoder. It can be downloaded and opened directly in a browser, with audio loading, editing, preview, and export working without runtime external connections.

View source on GitHub

Use together

Useful next steps and companion tools, organized around the workflow.

Trim practice recordings Music Practice Kit Trim saved practice recordings from Music Practice Kit or arrange several takes into one sequence. Inspect the exported audio Media Inspector Inspect the format, codec, bitrate, sample rate, and other media details of the exported file. Prepare montage music One Second Montage Trim or arrange your own audio before using it as background music in One Second Montage.