Online Audio Cutter,
trim and export with precision.

Field guide

How browser-based audio trimming works.

Traditional audio editing requires downloading a desktop application, importing a file, and navigating a complex interface before making a single cut. Browser-based audio editing using the Web Audio API eliminates all of that: your file is decoded entirely on your device, the waveform is rendered from raw PCM data, and the export is computed locally without any file ever touching a server.

This tool renders the cut using an OfflineAudioContext— a non-realtime rendering pipeline that processes your audio as fast as your CPU allows. For a 30-second clip from a 3-minute file, the rendering completes in under a second on modern hardware.

Using the waveform handles

The waveform visualizer shows the amplitude envelope of your audio across time. Two coloured markers overlay the waveform:

• The cyan "S" handle marks where your clip starts. Drag it right to trim silence or unwanted content from the beginning.
• The orange "E" handle marks where your clip ends. Drag it left to remove a fade-out, applause, or trailing silence from the end.

Both handles are draggable directly on the waveform canvas. You can also set precise values using the numeric inputs and sliders below the waveform. The two inputs enforce a minimum selection of 50 milliseconds and cannot cross each other.

Click-to-seek playback

Clicking anywhere on the waveform that is not a handle immediately moves the playhead to that position. If audio is already playing, it resumes from the new position. This lets you audition a specific section of a long track without scrubbing through it in real time, which is especially useful for finding an exact edit point in a speech recording or podcast.

Playback is confined to the selected range. The audio automatically stops when the playhead reaches the end handle, so you can loop your audition by pressing play again. The playhead returns to the selection start when you click the reset button.

WAV vs MP3: which format to choose

Both formats are supported for export. The right choice depends on how you intend to use the clip:

• WAV (lossless) preserves every sample exactly as it appears in the decoded audio. File sizes are larger (roughly 10 MB per minute for stereo 44.1 kHz audio), but there is no re-encoding quality loss. Use WAV when the clip will be edited further, used in a professional production, or imported into a DAW.
• MP3 (192 kbps) applies perceptual compression that discards audio information below the threshold of human perception. File sizes are roughly 1.4 MB per minute, making MP3 appropriate for web distribution, podcast segments, voice messages, ringtones, and any use case where file size matters more than absolute quality. 192 kbps is the standard high-quality setting used by most music streaming services.

How the MP3 export works

MP3 encoding in the browser is not natively supported by the Web Audio API, which outputs only raw PCM data. This tool uses LameJS, a JavaScript port of the LAME MP3 encoder, loaded on demand from a CDN the first time you request an MP3 download. Subsequent MP3 exports on the same page use the cached encoder with no additional network request.

The encoding process is: render the selection to PCM viaOfflineAudioContext, convert Float32 PCM samples to signed 16-bit integers, then feed 1152-sample chunks (one MPEG audio frame) through the LAME encoder. The resulting MP3 data chunks are concatenated into a Blob and downloaded directly from memory.

Privacy

Your audio file is never uploaded anywhere. All decoding, waveform rendering, trimming, and encoding happens entirely within your browser using the Web Audio API and the File API. Clearing your browser tab removes every trace of the audio from memory.