Audio Trimmer

How to use it

1. Choose an audio file in the box above.
2. Drag the blue handles on the waveform, or type Start and End in seconds.
3. Set Fade in and Fade out if you want the cut to begin and end softly, then press Preview selection to listen.
4. Press a Save button: WAV for the widest support, or Opus or AAC for a smaller file.

The output formats

WAV stores uncompressed PCM audio at 16 or 24 bits per sample, which every program can open. Opus, in an Ogg file with the .opus extension, is a compressed format that keeps speech and music clear at small sizes; the browser's own encoder makes it at 48 kHz. AAC-LC, in an ADTS stream with the .aac extension, is another compressed format; the browser encodes it at a rate the AAC standard allows.

Why this page does not write MP3

Browsers have no built-in MP3 encoder, and the open MP3 encoders, such as LAME, are licensed under the LGPL, which this site does not bundle. The page therefore writes WAV, Opus or AAC. The name of this tool includes MP3 because many people search for it; the files it makes are not MP3, and Opus or AAC give smaller files than WAV.

Fades and the cut

The selection is cut sample by sample at the file's own sample rate. A fade in and a fade out are straight-line ramps at the two ends of the cut. Each fade is limited to half of the selection, so the two never overlap. Preview plays the cut with its fades, so you hear what you will save.

Frequently asked questions