How to trim a video
- Drop an MP4, MOV or WebM on the box above — up to 2 GB.
- Play or drag the preview to where the good part starts and click Set start from player. Do the same for the end. Or type both times in seconds.
- Choose Exact (frame-accurate, re-encoded) or Fast (lossless, cut on the nearest key frame).
- Click Trim video, check the result next to the original, and download the MP4.
Exact or Fast?
A compressed video is stored as occasional complete pictures — key frames — with the frames in between described as changes from them. A cut that starts between two key frames can’t simply copy the data, because the first frames would be missing the picture they depend on.
Fast sidesteps that by starting at the key frame just before your chosen time and copying everything untouched. Nothing is re-encoded, so quality is identical and it finishes almost instantly — but the clip can begin a little early. macOS screen recordings have a key frame about every second, so the difference is at most about one second; our test iPhone video had one every 1.07 seconds.
Exact re-encodes the part you keep, so it starts and ends on exactly the frames you picked. It takes about as long as the clip itself on a laptop, and because the result is freshly encoded at a sensible bitrate, it is usually far smaller than the original too.
Measured on a real screen recording
Keeping 30 seconds (0:30–1:00) of a 148-second, 73 MB macOS screen recording, in Chrome:
| Mode | Time | Result | Length |
|---|---|---|---|
| Fast (lossless) | 0.3 s | 26.5 MB, original quality | 30.000 s |
| Exact | 22 s | 2.2 MB, re-encoded at high quality | 30.000 s |
Both came out exactly 30 seconds long here because the recording happened to have key frames on whole seconds. With other videos, Fast may keep up to a second extra at the start. In WebKit — the engine behind Safari — both modes worked, but Exact left out the audio of our iPhone test clip; the tool warns when that happens and Fast keeps the sound.
Trimming a Zoom, Teams or Meet recording
Meeting recordings usually open with a minute of people joining and end with goodbyes. Load the MP4, jump the preview to the first real sentence, set the start, jump near the end, set the end, and use Fast: meeting video is already heavily compressed, so a lossless cut is quick and keeps the audio exactly as it was. If you then need a smaller file for email, run the result through the Video Compressor.
What this tool doesn’t do
- Remove a section from the middle. It keeps one range. For a middle cut, trim twice and keep both halves, or use a timeline editor.
- Change the sound only. To drop the audio entirely, use Remove Audio from Video.
- Make a GIF. For a short looping clip, use Video to GIF, which has its own start and end controls.
Other ways to trim on a Mac
QuickTime Player can trim too: open the video, choose Edit › Trim…, drag the yellow handles, click Trim and save. For a quick lossless cut from Terminal, ffmpeg copies a range without re-encoding — like Fast mode, it snaps to key frames:
ffmpeg -ss 30 -to 60 -i recording.mov -c copy trimmed.mp4