Audio Trimmer

Cutting audio in your browser, losslessly and privately

An audio trimmer lets you keep just the part of a clip you care about — the chorus of a song, a single quote from an interview, or the usable take from a long recording. This one runs entirely as a web page, so your file is never uploaded. You load it, pick a start and end, and download a clean cut, all on your own device.

How browser-based trimming works

When you choose a file, the Web Audio API decodes it into raw audio samples in memory. To trim, the tool copies only the samples between your chosen start and end times into a new buffer using an OfflineAudioContext, then writes that buffer out as a WAV file. Because it is copying existing samples rather than re-encoding them, the cut is lossless and sample-accurate — the kept audio is bit-for-bit identical to the original.

Why the export is WAV

There is an asymmetry built into browsers: they can read MP3 and AAC but cannot write them, because the encoders are patent-encumbered and simply are not shipped. Exporting WAV sidesteps that by writing the samples out raw — the result is bit-perfect against the kept region, with no second generation of lossy compression stacked on your source. The cost is bytes: expect a WAV several times larger than the MP3 you fed in. If size matters more than fidelity for the final file, transcode the WAV to MP3 once at the very end of your edit.

Setting accurate start and end points

Play the file first and watch the timecode to find your in and out points, then type them into the start and end fields. Decimals are allowed, so 8.5 means eight and a half seconds. The end field displays the total duration so you never overshoot. If you want a clip that starts at the very beginning, leave start at 0.

Common uses

• Ringtones and alerts. Cut a few seconds out of a song for a custom tone.
• Podcast and interview edits. Pull a single answer or remove dead air from the ends.
• Sample prep. Isolate a loop or one-shot before importing into a DAW.
• Cleaning recordings. Drop the silence or fumbling before and after your take.

Editing unreleased audio without leaking it

The clips that most need trimming are often the ones you can least afford to hand around: a track that has not dropped yet, a session bounce covered by an NDA, interview tape with a named source. Because decoding and cutting both happen in an OfflineAudioContext inside this tab — and that buffer is freed the instant you leave the page — there is no upload step where the material could be copied or cached. You get a clean cut without your master ever sitting on someone else's disk.

Related media tools

• Audio Recorder — capture a fresh take, then bring it straight here to top and tail.
• Text to Speech — generate a spoken line, capture it, then trim it to length.
• Video Mute — for video, the audio-removal counterpart to this audio cutter.