Audio Editor

Trim, adjust and export using the menu bar above

Drop an audio file here

or click to browse — MP3, WAV, OGG, FLAC, AAC, M4A

Tip: use File menu or drag a file to get started

How to use the Audio Editor

  1. Load audio via the drop zone above, File → Open, Load from URL, or record directly from your microphone.
  2. Drag the Trim Start / Trim End sliders to select the section you want to keep.
  3. Adjust Volume, or open the Effects menu for gain, fades, EQ, noise reduction, and more.
  4. Use Edit → Undo/Redo at any point to step back through your changes.
  5. Export your result from the Quick Export buttons or File → Export as MP3, WAV, OGG, AAC, or FLAC.

Everything runs locally in your browser — no files are uploaded to a server.

How This Calculator Works

The CompelKit audio editor runs entirely in your browser using ffmpeg.wasm, so your files are never uploaded to a server. You can load an audio file, trim it to a region, apply effects (fade, normalize, speed, volume, EQ), and export to MP3, WAV, OGG, AAC, or FLAC. Editing is non-destructive: trims and effect settings are stored as parameters and applied during export, so you can adjust and re-export without quality loss from repeated re-encoding of the source. Multitrack mixing lets you layer two clips and balance their levels before export.

The Mathematical Formula & Logic

Trim region is encoded as a start time and end time (in seconds).

Export pipeline = ffmpeg filter chain applied to the source: trim → effects (fade, volume, atempo) → encoder (libmp3lame, pcm_s16le, libvorbis, aac, flac). Output file size follows the bitrate formula: (Bitrate × Duration) / 8 / 1024 MB.

Worked Step-by-Step Example

Trim a 3:00 clip to the first 2:30 by setting the end marker to 2 minutes 30 seconds, then export to MP3 at 128 kbps. The exported file is 2:30 long and about (128 × 150) / 8 / 1024 ≈ 2.34 MB — no upload, no server round-trip, the entire operation runs locally in your browser.

Frequently Asked Questions

Yes. All processing uses ffmpeg.wasm compiled to WebAssembly and runs locally in your browser tab. Your audio files are never uploaded to a server, so they stay on your device throughout editing and export.

Import supports MP3, WAV, FLAC, AAC, M4A, OGG, Opus, AIFF, and more. Export to MP3, WAV, OGG, AAC, or FLAC. WAV and FLAC are lossless; MP3, OGG, and AAC are compressed and let you choose a bitrate to balance quality and size.

No. Trims are stored as a region (start and end time) and applied once during export, so the source buffer isn't re-encoded until the final export. Repeated adjustments and re-exports don't compound quality loss the way repeatedly re-saving a lossy file would.

Disclaimer: CompelKit tools and calculators are provided for educational and estimation purposes only and do not constitute certified legal, financial, or tax advice.

Read the full guide: A Browser-Based Audio Editor Explained →
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