Donaldson R F Trim & Cut Video
Keep just the part of a video you want, or cut a section out of the middle. Pick a fast cut that does not touch the picture, or a precise cut that is exact to the frame — all in your browser, nothing uploaded.
How it works
Type the start and end time of the part you want, or play the video and press Use the player’s current time at the right moments. Choose Keep to save only that part, or Remove to cut it out and join what is left before and after it.
The work is done by ffmpeg compiled to WebAssembly. That engine is about 31 MB. It is downloaded only when you press Cut video, checked against a known fingerprint, and stored in your browser, so the next time it starts at once. It runs in the background, so the page stays responsive, and you can press Cancel at any time.
Precise or fast?
Fast copies the video without decoding it, so it takes seconds and the quality is exactly the original. The catch is that a video can only be cut without re-encoding at a keyframe, a complete picture that appears every few seconds. The clip therefore starts at a keyframe near your start time, which can be up to a few seconds earlier or later, and the page tells you when the length differs from what you asked for. It is the right choice for long videos and for trimming off the beginning and end roughly.
Precise decodes the video and encodes the part you keep again (H.264 video with AAC sound in an MP4, or the same kind of file for MKV, MOV, WebM and AVI), so the cut is exact to the frame. It is slower, because a browser has to do all the work on a single processor thread: expect roughly half of real time for 720p video and a quarter of real time for 1080p, so a one-minute 1080p clip takes several minutes. The page shows an estimate. Re-encoding is very slightly lossy.
Removing a section from the middle always uses the precise method, because the two remaining pieces have to be joined smoothly.
Frequently asked questions
Is my video uploaded?
No. The only download is the conversion engine itself. Your video is opened directly from your disk and never sent anywhere.
Why does my player not show this video?
Browsers can play only some file types (MP4 with H.264 is the safest). If the preview stays black, the tool can still cut the file; the result is saved in the same kind of file.
What is the biggest video I can use?
The limit is shown at the top of the page. The finished clip is built in memory before you can save it, so on a phone or an older computer choose a smaller file if the tool reports that it ran out of memory.
Will it work with protected videos?
No. Videos protected by copy protection (DRM), such as many downloaded films or streaming-service files, cannot be read. Only use videos you have the right to use.
Related tools: Mute Video, Extract Frames from Video, Extract Audio from Video.