Trim, Cut and Fade Audio
Keep the part of a song or recording you want, join several, fade it in and out. MP3 and M4A lose nothing. Nothing is uploaded.
Runs entirely in your browser
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Your sound file is opened by this page and never uploaded. MP3 and M4A are cut without re-encoding, in WebAssembly, so nothing is lost.
Open a song, a voice memo or a podcast and its waveform fills the timeline, so you can see the quiet gaps and the loud parts. Drag the handles to the stretch you want, or type the times, or play it and press Start here and End here. To keep more than one stretch, the chorus twice, an interview without the ums, press Add a part; the parts are joined in order, and Play plays them that way.
Fade in and fade out over half a second to five, and turn it up or down a few decibels, which is what a ringtone or a clip for a video wants. An MP3 is cut and faded without re-encoding: its frames are kept as they are and the fades are written into each frame's own volume, the trick mp3gain uses, so not a bit of quality is lost. An M4A, including an iPhone voice memo or ringtone, is cut as it is too. WAV, OGG, FLAC and anything else your browser plays is decoded here and saved as WAV.
Nothing is uploaded. The file is opened in this tab and cut here, in WebAssembly, and the page is served with a rule that forbids it from opening a connection to anywhere.
How to use it
- Choose a sound file, or drop it on the page. It is never uploaded.
- Drag the handles on the waveform to the part to keep. Add a part to keep more than one.
- Pick a fade in, a fade out or a change of volume if you want one, and press Play to hear it.
- Press Trim and download.
Questions
Does cutting an MP3 lower its quality?
No. The MP3's frames are copied into the new file as they are, never decoded and encoded again, so it sounds exactly as it did. Even the fades and the volume change are made without re-encoding, by changing the gain each frame already carries.
How exact is the cut?
An MP3 is cut to the frame, about 26 milliseconds, which is finer than you can hear. An M4A is cut to its own frames, about 23 ms. WAV is cut to the sample.
How do I make a ringtone?
Choose the song, keep up to 30 seconds of it, add a short fade in and out, and download. Android takes the MP3 as it is. For an iPhone, start from an M4A, or save as WAV and convert it, and rename the file to .m4r before adding it in Finder or iTunes.
Why is there a moment of quiet where two MP3 parts join?
An MP3 frame can borrow a little data from the frames before it, and after a join those are different frames, which would click. The first frame of each joined part, 26 ms, is made silent instead.
Which files can it open?
MP3 and M4A (AAC) are cut as they are, at any length. WAV, OGG, Opus, FLAC and any other format your browser can play are decoded in the page and saved as WAV, which works up to a few hundred megabytes.
Is my file uploaded?
No. The page reads the file in this tab and writes the trimmed copy here; it is served with a security policy that forbids it from opening any network connection.
Your data stays on your device
Everything above runs inside your browser as WebAssembly compiled from Rust. Nothing you type is uploaded, logged or stored on a server. You can load this page once, go offline, and it still works.
This page makes no requests at all, to anywhere. That is not a promise in the copy: it is a Content-Security-Policy header your browser enforces, and connect-src on it is none. Open the network tab and watch nothing happen.