How do I trim an MP3 without losing quality?

Keep the output format the same as the input and leave the lossless copy option on. The audio stream is copied rather than re-encoded, so there is no quality loss at all — the only compromise is that the cut lands on the nearest frame.

Why does adding a fade force a re-encode?

A fade changes the sample values themselves, and you cannot alter samples without decoding and re-encoding them. A stream copy passes the compressed data through untouched, which leaves no opportunity to apply a filter.

Can I extract a section of audio from a video?

Yes. Drop the video in and the audio track is trimmed and exported on its own — the video stream is discarded, so you get a clean audio file.

What bitrate should I choose for a trimmed MP3?

192 kbps is transparent enough for music on most systems and 128 kbps is fine for speech. Going above the source bitrate never recovers detail — it just makes the file bigger.

Is there a file size limit?

No fixed limit, but everything runs in your browser's memory, so very long recordings use more RAM and take longer. Files of an hour or two are comfortable on a typical machine.

Audio Trimmer

Cut a clip out of an audio file with optional fades, losslessly when the format allows and precisely when it does not.

The Audio Trimmer runs entirely in your browser. Your recording is never uploaded, stored or sent to a server.

Open the Audio Converter

关于 Audio Trimmer

Cutting audio has one subtlety that video does not. A stream copy is instant and completely lossless, but it can only cut on a frame boundary, so a trimmed MP3 may begin a few milliseconds early or late. Re-encoding lands exactly on the mark and is the only way to add a fade, at the cost of one generation of compression. This trimmer offers both and says plainly which applies, rather than choosing quietly. Seeking happens before the file is decoded, which is what keeps a cut from the middle of a long recording fast even on a large file, and everything runs on your device — a two-hour interview never leaves your machine.

功能特性

Start and end times in seconds, m:ss or h:mm:ss with milliseconds
Lossless stream copy when the output format matches the input
Fade in and fade out, measured from the trimmed clip
Export to MP3, WAV, M4A, OGG or FLAC
Bitrate control for lossy formats, with a size estimate
Reads the audio track out of a video file too
Duration filled in automatically from the file
Nothing is uploaded — audio is processed in your browser

如何使用 Audio Trimmer

Drop an audio file, or a video to take its audio
Set the start and end of the section you want
Add a fade if the cut lands mid-phrase
Trim and download the clip

示例

输入

Cut 0:10 to 0:40 from an MP3, with a 2 second fade out

输出

30 second MP3 · fade filter afade=t=out:st=28:d=2

The fade is positioned relative to the trimmed clip, not the original file.

常见错误与故障排除

The clip starts a fraction of a second before the chosen point. — That is the stream copy landing on the nearest frame boundary. Turn the lossless option off to re-encode, which cuts exactly where you asked.
The lossless option is greyed out. — A stream copy only works when the output format matches the input and no fade is applied. Change the output format to match the source, or accept the re-encode.
The trimmed file is larger than expected. — WAV and FLAC are uncompressed or lossless, so a minute of stereo WAV is about 10 MB regardless of the source. Choose MP3 or M4A and set a bitrate if size matters.

常见问题

How do I trim an MP3 without losing quality?: Keep the output format the same as the input and leave the lossless copy option on. The audio stream is copied rather than re-encoded, so there is no quality loss at all — the only compromise is that the cut lands on the nearest frame.
Why does adding a fade force a re-encode?: A fade changes the sample values themselves, and you cannot alter samples without decoding and re-encoding them. A stream copy passes the compressed data through untouched, which leaves no opportunity to apply a filter.
Can I extract a section of audio from a video?: Yes. Drop the video in and the audio track is trimmed and exported on its own — the video stream is discarded, so you get a clean audio file.
What bitrate should I choose for a trimmed MP3?: 192 kbps is transparent enough for music on most systems and 128 kbps is fine for speech. Going above the source bitrate never recovers detail — it just makes the file bigger.
Is there a file size limit?: No fixed limit, but everything runs in your browser's memory, so very long recordings use more RAM and take longer. Files of an hour or two are comfortable on a typical machine.