Trim Video — Cut the Start and End

How to use it#

Drop a video onto the box above, or click it to choose one.
Play or drag the video to where it should start and press Set from video beside Start, then do the same for End. The times can also be typed.
The cut is made as soon as the times settle. Play it in the preview, then download it.

Why the picture is encoded again#

A video is stored as a full picture every second or two, called a keyframe, with only the changes in between. A cut that copied the compressed video as it was would have to start on a keyframe, so it would either begin up to a couple of seconds early or carry those seconds along with a note asking players to skip them. Some players ignore that note: they show the video as longer than the cut, and their progress bar runs behind the picture.

So the picture is encoded again from the frame you chose, at a high quality and never at more than the bitrate of the original. The result starts where you asked in whatever plays or edits it. It loses a little detail, which at this quality is very hard to see, and it takes longer than a copy would, more so for a long or 4K video. An HEVC video, as an iPhone records, stays HEVC where the browser can make it and becomes H.264 where it cannot, and a video shot at more than 60 frames a second comes back at 60.

The sound is copied as it was, cut at the same points. The cut keeps the format you gave it: a MOV comes back as a MOV, an MP4 as an MP4, and a WebM or MKV as the same. The date, place, and phone model a video records are kept too; to see them or take them out, use the video metadata viewer.

Cutting a video to fit a size limit#

Shortening a video is often the quickest way to make it small enough to send, because the size of the cut falls with its length: half the video is about half the file. The page shows the real size before you download.

When the part you want is still too large, compress video has the same Start and End fields and lowers the bitrate as well, working out how much from the length you kept and the size it has to fit. It also turns the cut into an MP4, which suits a WebM or an MKV that has to play on a phone.

Frequently asked questions#

Does trimming a video lose quality?

Very little. The picture is encoded again from your start, at a high quality and at no more than the bitrate of the original, so the difference is hard to see. The sound is copied as it was.

Why not just copy the video without re-encoding?

A copy can only start on a keyframe, which can be a second or two before where you want to begin. The way around that, keeping those seconds with a note to skip them, confuses some players, which can show a one-second cut as two seconds long, with a progress bar that never catches up. Encoding again makes a cut that plays the same everywhere.

How do I cut the first few seconds off a video?

Set Start to the moment the part you want begins, and leave End on the length of the video, where it starts. To cut the end off instead, leave Start at 0 and bring End back. Either way the rest of the video is kept, and the page shows the new length and size before you download.

How precise can the start and end be?

The fields take times to a tenth of a second. Set from video takes the moment the preview is paused on, to the nearest tenth of a second, so pause on the frame you want and press it. An end at or past the end of the video keeps everything to the end.

Can I cut out the middle of a video?

Not on this page, which keeps one part, from the start you set to the end you set. To remove a section from the middle and join what is left, use cut out part of a video.

Can I trim a video on an iPhone?

Yes. The page works in Safari on an iPhone: tap the box, choose Photo Library, and pick the video. iOS hands the page a converted copy rather than the original, usually as H.264. The cut is saved in the Files app, where it shows under Recents, and Share, then Save Video, puts it in Photos.

Why is it slow?

To cut on the exact frames you pick, the part you keep is encoded again, frame by frame. Your file never leaves your device, so the work is done by your own computer or phone, inside this browser tab, not on a server built for it. Every frame is decoded and compressed again: a minute of 1080p at 30 frames a second is 1,800 pictures of about two million pixels each, and 4K has four times as many pixels. The browser hands the compression to your device's video chip where it has one, but each frame still passes through the tab, which shares the processor with everything else that is open. A phone also slows itself down as it warms up, and some browsers slow a tab you switch away from, so keeping this tab in front, closing other tabs, and plugging a phone in all help.

Is my video uploaded?

No. The video is read and cut inside this browser tab, and the result is handed straight to your downloads. Nothing is sent to a server.