Video Trimmer

Video Trimmer

Cut the part of a video you need. Use fast, keyframe-aligned trimming that keeps the original quality, or an exact re-encoded cut for WebM videos — all processed on your device.

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1. Video file

Local · not uploaded

Drop a video here

or click to browse

MP4 · WEBM · UP TO 500 MB

Processing uses the bundled open-source libav.js engine (FFmpeg libraries, LGPL-2.1), loaded from this site only. Licences and source code.

2. Clip & mode

Fast or accurate

Trim mode

About this tool

About Video Trimmer

Video Trimmer cuts MP4 and WebM videos in your browser. Fast mode copies the original video and audio without re-encoding, starting at the nearest keyframe at or before your chosen start, so quality is unchanged. Accurate mode, for WebM files with VP8 or VP9 video, decodes and re-encodes the exact range to VP8 and Opus. Both modes use libav.js, an open-source WebAssembly build of FFmpeg’s libraries loaded from this site.

Trimming a clip for sharing or removing a long intro should not require uploading a private video. Video compression only allows clean starts at keyframes, so fast trimming is quick and lossless but may start a little early; exact cuts require re-encoding, which is slower and reduces quality slightly. The tool shows exactly which mode does what, and its file-size, resolution and duration limits keep the browser from running out of memory.

How to use

Step by step

  1. Drop an MP4 or WebM video onto the upload area.
  2. Check the preview, length, dimensions, codecs and file size.
  3. Set the start and end with the handles, exact times or the playback position.
  4. Choose Fast (keyframe-aligned, no re-encoding) or Accurate (re-encoded, WebM VP8/VP9 only).
  5. Read the note showing where the clip will actually start, then press Trim video.
  6. Watch the trimmed clip and download it.
Key features

What it offers

  • Fast keyframe-aligned trimming of MP4 and WebM without re-encoding
  • Accurate re-encoded trimming for WebM VP8/VP9 with Opus or no audio
  • Shows the keyframe a fast trim will start from before you trim
  • Range handles, exact time fields and playback-position buttons
  • Keeps the audio track (copied in fast mode, re-encoded as Opus in accurate mode)
  • Preview of the trimmed result before download
  • Clear limits for file size, resolution and clip length
  • Runs locally in a worker — nothing is uploaded
Best practices

Tips for best results

  • Use Fast mode whenever a slightly earlier start is acceptable — it keeps full quality.
  • Use Accurate mode only for short WebM clips that must start on an exact frame.
  • Leave a little extra at the start when keyframes are far apart.
  • Check the result’s first and last seconds before sharing it.
  • Keep the original video until you are happy with the clip.
Benefits

Why people use it

Lossless option

Fast mode keeps the original quality.

Exact option

Accurate mode cuts WebM precisely.

Private

Videos never leave your device.

Transparent

Keyframe positions and limits are shown.

FAQ

Common questions

Fast mode copies the original video and audio without re-encoding, so quality is unchanged and it is quick — but the clip must start at a keyframe, so it may begin slightly before your chosen start (the tool shows the exact time). Accurate mode decodes and re-encodes the exact range, so it starts exactly where you choose, but is slower and slightly reduces quality.
Fast mode: MP4 and WebM files (the original codecs, such as H.264 or VP9, are copied unchanged). Accurate mode: WebM files with VP8 or VP9 video and Opus or no audio; the output is WebM with VP8 video and Opus audio. MOV, MKV, AVI and accurate MP4 trimming are not supported.
No. The video is read and trimmed in your browser by a bundled open-source engine (libav.js, FFmpeg libraries compiled to WebAssembly) loaded from this website.
Yes. Fast mode copies the audio track as it is. Accurate mode re-encodes Opus audio; WebM files with other audio codecs cannot use accurate mode.
Compressed video can only start cleanly at a keyframe. Fast mode uses the last keyframe at or before your start time; the tool shows which keyframe will be used before you trim.
Fast mode: files up to 500 MB. Accurate mode: files up to 200 MB, videos up to 1280 × 720 pixels and clips up to 60 seconds, because re-encoding in the browser is slow and memory-intensive.
The preview uses your browser’s own player. If your browser cannot play a codec, you can still trim the file in Fast mode.

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Private by design

This runs entirely in your browser

No file or text you enter here is uploaded. Encoding and decoding happen on your device using native browser APIs — close the tab and nothing remains on a server.

Install Toolisco Add it to your device for offline, one-tap access.