Audio Trimmer
Set in and out points on a waveform and export just that clip, without re-encoding when the format is unchanged.
What is Audio Trimmer?
A waveform-based audio cutter for trimming ringtones, podcast segments, samples and voice memos. You set an in point and an out point on the waveform and export the slice.
How it works
The file is decoded locally with the Web Audio API to draw an accurate waveform envelope and give exact timings. The export then runs through the bundled ffmpeg engine: keeping the original MP3, WAV, OGG or M4A format copies the audio frames without re-encoding, while choosing a different format re-encodes only the selected range.
- Load your file. Drag a file onto the drop zone or pick one from your device. It is read locally by the browser and never uploaded.
- Set the options. Adjust the handles, format, quality or threshold controls — the preview updates as you change them.
- Process and download. Run the tool, then download the result. Compare the reported before/after size for compressors and converters.
Examples
A 42 MB podcast episode → 9 MB MP3
Trim the intro, normalise to −16 LUFS, and export at 96 kbps mono — a typical interview lands around a fifth of the original size.
A phone video with the wrong orientation
Rotate 90° and the width/height swap in the output, so it plays upright in every player instead of relying on metadata flags.
Common mistakes
Expecting instant encoders
Video encoding runs in single-threaded WebAssembly, so a clip takes roughly its own length (or a little longer) to re-encode. Stream-copy operations are near-instant by comparison.
Re-encoding when a copy would do
Trimming, removing audio and joining same-codec clips can copy streams without re-encoding — pick the copy option when it is offered to avoid any quality loss.
Ignoring the first-load download
The media engine is about 31 MB and is fetched on first use, then cached. The first conversion on a connection is slower than every later one.
Frequently asked questions
Does trimming reduce audio quality?
Not when you keep the original format — the clip is copied at the frame level with no re-encode. Converting to a different format does re-encode, which is why the tool tells you which mode it used.
Can I trim without loading the 31 MB engine?
Yes for WAV: if the source is already WAV and you keep WAV, the cut happens in the browser's audio graph. The wasm engine is only fetched for the formats it has to encode.
How accurate are the cut points?
Re-encoding is sample-accurate. Stream copy can only cut on a frame boundary, so an MP3 clip may include a few milliseconds of the neighbouring audio.