Are my files uploaded to a server?

No. This conversion runs inside your browser using your own device’s processing power, and the file is not uploaded. Once a tool has been used once (video, text recognition and background removal download their engine from this site the first time), it keeps working when your connection drops.

Does trimming lose quality?

Not with the fast cut: the picture and sound are copied exactly as they are. The precise cut re-encodes the picture to H.264 at a bitrate never above the original’s.

What format do I get back?

An MP4. The fast cut keeps the original H.264, HEVC, MPEG-4 Part 2 or AV1 picture as it is; any other picture, and every precise cut, is encoded to H.264. AAC, MP3, AC-3, E-AC-3 and ALAC sound is copied as it is, anything else becomes AAC. If the source uses a codec MP4 cannot carry, the picture is re-encoded automatically and the tool tells you so.

Trim a video: cut the start and the end

Runs on your device · Your file never leaves your device.

Scrub to where the good part begins, press "Set start here", scrub to where it ends, press "Set end here", and download only that. The quick buttons cut the first 10, 15, 30 or 60 seconds for a story, a status or a short. Times can also be typed as mm:ss or plain seconds.

By default the cut is a stream copy: the video and audio are not re-encoded, so it finishes in seconds even on a long recording and the picture is byte-for-byte what it was. The trade-off is honest — a copy can only start on a keyframe, so the clip starts on the keyframe at or before the time you chose, which can be a few seconds earlier, depending on the file. Switch on "Precise cut" and the clip is re-encoded to H.264 for a frame-exact edge.

Everything runs on your device with a video engine that downloads once (about 30 MB) and is then cached. Files over 1 GB are trimmed in parts that fit in memory, each a complete MP4: when together they fit, they are joined back into one file; otherwise the Join mode of the video converter puts them back together. The file itself never leaves your browser.

How to trim a video

Add the video and, if you like, press Inspect to see its length.
Set the start and end — from the preview, the quick buttons, or by typing times.
Press Trim and download the MP4.

Supported formats and limits

Input: MP4, MOV, MKV, AVI, WebM, MPG, 3GP, TS, VOB and more
Output: MP4 (picture copied or H.264; sound copied as is, or AAC)
Fast cut: Stream copy from the keyframe at or before the start — no re-encoding, no quality loss
Precise cut: Frame-exact, re-encoded to H.264
Where it runs: In your browser; nothing uploaded

Not for: Cutting several pieces out of the middle in one go — trim keeps one continuous range; run it twice and put the two pieces together with the video converter’s Join mode.

What the fast cut actually does

With Precise cut off, nothing is decoded. The tool finds the last keyframe at or before your start, copies the picture and sound from there, and stops at your end. So only the start can move, and only earlier: in a file with a keyframe every 5 seconds, a cut from 0:07 to 0:12 comes out as 0:05 to 0:12.

How far back depends on how the file was recorded, because cameras and programs space their keyframes differently. The quick buttons are not affected: they start at 0:00, and a video begins with a keyframe.

When the picture is encoded anyway

The result is always an MP4, and the fast cut can only copy a picture that MP4 holds as it is: H.264, HEVC, MPEG-4 Part 2 (DivX, Xvid) or AV1. Anything else, such as VP8 or VP9 from a WebM, MPEG-2 from a DVD or many MPG files, or WMV, is encoded to H.264 even with Precise cut off, and the note under the result says so. The same happens when the engine cannot name the codec. Such a cut is frame-exact as well.

How the precise cut works

With Precise cut on, only the part you keep is encoded: for a 30-second clip from a two-hour film, that is 30 seconds of video. Your device's own video encoder does it when it can, the built-in engine otherwise; /rotate-video explains when each one is used. The engine jumps to the keyframe before your start, decodes forward and drops every frame before the exact point, so it never decodes the film from the beginning.

Typing times, and very large files

Times can be typed as 90, 1:30 or 1:02:03, with a decimal point for parts of a second, such as 12.5; Eastern Arabic and Persian digits are read too. Set start here and Set end here take the player's time to a tenth of a second. The player needs a format your browser can play; where it cannot, typed times work the same.

When the source is over 1 GB, the engine works through the part you keep in pieces, and on a fast cut each piece starts on the keyframe where the previous one ended, so nothing repeats at the seams. The pieces are joined into one MP4 when the whole result fits in about 350 MB; otherwise each is offered as its own numbered MP4.

Frequently asked questions

Are my files uploaded to a server?: No. This conversion runs inside your browser using your own device’s processing power, and the file is not uploaded. Once a tool has been used once (video, text recognition and background removal download their engine from this site the first time), it keeps working when your connection drops.
Why does my clip start slightly before the time I set?: The fast cut copies the streams without re-encoding, and a copied stream can only begin at a keyframe, so the clip starts on the keyframe at or before the time you chose, which can be a few seconds earlier, depending on the file. Turn on "Precise cut" to have the clip re-encoded and start on the exact frame.
Does trimming lose quality?: Not with the fast cut: the picture and sound are copied exactly as they are. The precise cut re-encodes the picture to H.264 at a bitrate never above the original’s.
What format do I get back?: An MP4. The fast cut keeps the original H.264, HEVC, MPEG-4 Part 2 or AV1 picture as it is; any other picture, and every precise cut, is encoded to H.264. AAC, MP3, AC-3, E-AC-3 and ALAC sound is copied as it is, anything else becomes AAC. If the source uses a codec MP4 cannot carry, the picture is re-encoded automatically and the tool tells you so.