How to Trim an MP3 or WAV File in the Browser

To trim an MP3, WAV, M4A, or FLAC file, use Zro7 MP3 Cutter. Drop the file, drag handles on the waveform (or type exact timestamps), and download the trimmed segment. Lossless copy when the format allows; re-encode when frame-accuracy is needed. All in your browser.

Lossless MP3 trimming is possible

MP3 frames are typically ~26 ms long. Cutting on frame boundaries copies frames without decoding — zero quality loss. Zro7 does this by default; the cut lands at the nearest MP3 frame (within a few milliseconds of your request). For sample-accuracy (needed to remove a specific plosive or edit music down-beat), toggle re-encode mode.

Format matrix

• MP3 — lossless frame-boundary trim by default.
• WAV — sample-accurate trim, always lossless (PCM).
• M4A / AAC — frame-boundary trim losslessly; re-encode for sample accuracy.
• FLAC / OGG — decoded and re-encoded losslessly to preserve edit boundaries.

Steps

1. Open MP3 Cutter.
2. Drop the audio file. Waveform renders in a couple of seconds.
3. Drag start/end handles or type timestamps like 00:01:23.400.
4. Preview the trimmed segment.
5. Click Cut and download.

Common workflows

• Extract a 30-second sample from a song for a demo reel.
• Cut the pre-roll silence off a voice memo.
• Split a two-hour interview into speaker segments (do it repeatedly).