Trim and cut audio files
Cut MP3, WAV, M4A, FLAC and OGG files with a dual-handle slider, exact timecodes, optional fades and a lossless copy mode. No upload.
- Runs in your browser
- Files are never uploaded
- Free, no account
First use downloads the 10 MB video engine from this site. After that it is cached and works offline. It is WebAssembly served from onthisdevice.com — no third-party CDN — and your file is still processed entirely on your own device.
How to trim an audio file
- Drop in an MP3, WAV, M4A, FLAC, OGG or Opus file. It loads into a player immediately.
- Drag the two handles to the section you want to keep, or play the track and press Set here to capture the playhead position.
- Type exact timecodes —
0:45,1:23.75,1:02:30— when you need to be precise to the hundredth of a second. - Keep Lossless mode unless you want a fade or a different output format.
- Press Trim audio, check the preview, and download.
Lossless trimming, and where its limits are
In copy mode the encoded audio is passed straight through: no decode, no re-encode, no generation loss. The one caveat is that compressed audio is stored in frames, so a cut lands on the nearest frame boundary rather than the exact sample.
| Format | Frame length | Worst-case cut error |
|---|---|---|
| MP3 at 44.1 kHz | 1152 samples | ≈ 26 ms |
| AAC (M4A) | 1024 samples | ≈ 23 ms |
| Opus | 20 ms default | ≈ 20 ms |
| WAV / FLAC | Sample accurate | None |
Twenty-something milliseconds is roughly a fiftieth of a second — inaudible in speech and music alike. It only matters when you are cutting to a beat grid, in which case re-encode mode gives you a sample-exact edit.
Fades
A fade rewrites the samples themselves, so it cannot be done with a stream copy. Setting a fade length switches the tool to re-encoding automatically and tells you it has. A 0.5-1 second fade in and out removes the click you otherwise get when a cut lands mid-waveform, and is worth adding to almost any clip taken from the middle of a recording.
Making a ringtone or an alert sound
- Trim the section you want — 20-30 seconds is the usual maximum for a ringtone.
- Add a short fade out so it does not end abruptly if it plays to the end.
- Convert to the format your phone wants: Android happily takes MP3, iPhone wants M4A (an M4R is simply an AAC file renamed).
- Copy it to the device — no account, no upload, and the original recording never leaves your computer.
Why there is no waveform
Drawing a waveform requires decoding the whole file to PCM before you can touch anything, which on a two-hour recording means a long wait and a great deal of memory — on a phone it may not finish at all. This tool takes the opposite approach: the browser's own player gives you instant scrubbing, and the "Set here" buttons transfer the playhead into the start or end field to the hundredth of a second. You get precision without the wait.
Questions
Is the cut lossless?
In copy mode, yes — the encoded samples are copied straight through with no decode/encode cycle. MP3 cuts snap to the nearest frame boundary, which is about 26 milliseconds, so the difference is inaudible.
How do I add a fade in or fade out?
Open "Fade in / fade out" and set a length in seconds. Fades change the samples, so the tool switches to re-encoding automatically and tells you it has done so.
Can I make a phone ringtone with this?
Yes. Trim the section you want, then convert it with the audio converter if your phone needs M4A or a specific bitrate. Everything stays on your device, so private recordings never leave it.
Why can I not see a waveform?
Drawing a waveform means decoding the entire file up front, which is slow for long recordings. Instead you get an audio player, a precise dual-handle slider and a "Set here" button that copies the playhead position into either field.