Audio Trimmer

How to Trim an Audio File Online

1. Drop your audio file onto the upload area. MP3, WAV, M4A, OGG, FLAC up to 500 MB are accepted.
2. Listen to the preview player to find the start and end points of the section you want to keep.
3. Type the start and end seconds into the trim range fields. The output length is shown live.
4. Press Trim audio. The file uploads to our EU servers, FFmpeg cuts the section using stream-copy (lossless), and you download the result.
5. Both files auto-delete from our servers within 15 minutes.

Why stream-copy keeps quality intact

The trimmer uses FFmpeg's -c copy mode: the audio stream is copied byte-for-byte from the source into the output without going through the encoder. The result is sample-perfect identical to the matching range in the original file - no transcoding loss, no second-generation MP3 artifacts. The downside is that the cut snaps to the nearest keyframe of the source codec, which for MP3 means roughly 26 ms granularity. That is finer than human perception for almost every practical use case.

If you need frame-accurate cuts (down to a single sample) you would need a re-encode pass - we may add that as an option in a future version. For ringtones, podcast highlights, voice memo trimming and music sample extraction the default copy mode is the right choice.

Common use cases

• Make a ringtone. Trim a 30-second hook out of a song; iOS expects an M4A under 40 seconds.
• Highlight a podcast moment for sharing on social. Cut the 60 most quotable seconds out of a 90-minute episode.
• Clean up a voice memo by removing the awkward few seconds at the start before recording started or the dead air at the end.
• Sample music for a video edit, demo or remix.
• Cut audiobook chapters into separate files matching chapter boundaries.

How to find your start and end points

Accurate trims start with accurate timestamps. The preview player on the page shows the current position, and you can pause at the exact moment you want and click "Use playhead" to capture it into the start or end field. If you prefer, type the times directly as MM:SS - the output length updates live so you can confirm the clip is the duration you expect before pressing Trim. For a hook or chorus, scrub the slider a few seconds wide on each side first, then tighten once you have heard where the natural boundaries fall. Most music phrases begin on a downbeat, so nudging the start a fraction earlier and letting the silence trim itself sounds cleaner than cutting exactly on the first note.

Trim versus convert: which tool do you need

This trimmer keeps the output format identical to the input because stream-copy cannot change the codec while copying packets. If your goal is only to shorten a file and keep its quality, the trimmer is the right and fastest choice. If you also need to change the format - say, an M4A you want as MP3, or a WAV you want compressed to save space - run the file through the audio converter, which re-encodes and can change container and bitrate in one pass. To pull a clip out of a video soundtrack, the extract audio from video tool drops the video track and hands you the audio, which you can then trim here. To see a visual representation of where the loud and quiet sections sit before cutting, the audio waveform generator can help you eyeball the boundaries.

What stream-copy does and does not change

Because no encoder runs, stream-copy never touches the audio fidelity, the bit depth, the sample rate or the channel layout - the trimmed range is the same bytes that were in the source. What it does change is length and, marginally, the position of the very first frame, which snaps to the nearest codec boundary as described above. It also means you cannot use this mode to repair a damaged file, normalise volume, or change loudness; those require decoding and re-encoding, which is a converter job, not a trim. If the preview will not play or the duration reads 0:00, the file's metadata is unreadable and the trimmer cannot compute valid bounds - re-export the source from its original app and try again.

Privacy and limits

The accepted formats are MP3, WAV, M4A, OGG and FLAC, up to 500 MB per upload, which covers roughly ten hours of CD-quality stereo WAV or well over a hundred hours of typical MP3. Files travel over HTTPS to our EU server, FFmpeg performs the cut there, and the trimmed result is offered through a signed, time-limited download URL. Both the upload and the output are deleted within 15 minutes, and the signed link stops working at the same time. Nothing about the audio content is logged, transcribed or retained beyond that window. For files past the size cap, you can run the same operation locally with ffmpeg -ss START -to END -i input.mp3 -c copy output.mp3.