Trim an Audio File

Trim audio in your browser

Pick an audio file, set a start and end time in seconds, and choose what to do with that selection: keep extracts just the selection (the classic ringtone cut), remove deletes it and joins what's left (drop an ad break or a cough from a recording). Leave End empty to trim to the end of the track — set only Start to 15 and you've dropped the first 15 seconds. The trim runs entirely in your browser with ffmpeg compiled to WebAssembly, so your audio is never uploaded to a server.

Worked example

Cut a 30-second ringtone out of a song: upload the song, set Start to 15, End to 45, leave Mode on keep and Format on mp3, and tick Fade edges so the clip doesn't start or end with a click. The result is a 30-second mp3 (192 kbps) named like the original with a -trimmed.mp3 suffix. To instead delete seconds 15–45 from the song and keep the rest, switch Mode to remove. To cut a rambling intro off a recording, set Start to where the good part begins and leave End empty.

Modes

• keep — output is exactly the [start, end] selection, sample-accurate.
• remove — output is everything except the selection. With an explicit end, the cut lands on the nearest audio frame (roughly 20–40 ms), which is inaudible for most edits; with End empty (delete-to-the-end), the cut is sample-accurate.

Formats

• MP3 — lossy at 192 kbps; small and playable everywhere (the default).
• WAV — lossless 16-bit PCM; largest, ideal for further editing.
• OGG — lossy Vorbis at 192 kbps; open format, good quality per byte.
• FLAC — lossless and compressed; smaller than WAV, still a perfect copy.
• M4A — AAC in an mp4 container; good quality at small sizes.

Limits and edge cases

• Input files up to 10 MiB; anything ffmpeg can decode works (mp3, wav, flac, m4a/aac, ogg, opus, and most video containers' audio tracks).
• The audio is always re-encoded (the trim filters require it), so keep with the same format still writes a fresh 192 kbps mp3 rather than a bit-exact copy.
• Fade edges applies up to a 0.5 s fade-in and fade-out inside the kept selection (shorter on clips under 2 s so the fades never overlap). With End empty the length isn't known up front, so both fades are a flat 0.15 s — enough to kill clicks, but a kept remainder shorter than ~0.3 s will still come out strongly attenuated; give very short clips an explicit end. Fade only works with keep mode — in remove mode the output length isn't known up front, so the option reports an error instead of silently doing nothing.
• End empty (or 0) means "to the end of the track"; otherwise end must be greater than start. Times beyond the file's real length are clamped by ffmpeg to the end of the audio.
• Start 0 with an empty End selects the whole file — that's nothing to trim, so the tool asks you to set a start and/or end instead of silently re-encoding.

FAQ