Video Trimmer & Cutter
Cut a video down to the part you want — instantly and losslessly, or to the exact frame.
Mark the cut
Keys (outside the time boxes): Space play/pause · ← → or , . one frame · Shift + ← → one second · I / O set start / end of the selected range. A focused handle moves with ← →.
Fades to and from black, with the sound faded too. Fades need Exact mode.
What will happen
About the Video Trimmer & Cutter
Trim the beginning or end of a video, or cut one or more sections out of the middle, by dragging handles on a thumbnail timeline, stepping frame by frame, or typing exact times. Mark the parts you want to keep or the parts you want to remove.
Lossless mode copies the original video and audio data, so it finishes in seconds and the quality is exactly the original; the cuts move to the nearest keyframes (the frames a video can start from), and the page shows you where. Exact mode re-encodes the video so every cut lands on the frame you chose, and can add a fade in or fade out. The file keeps its format (MP4, MOV, MKV or WebM). Everything happens in your browser — the video is never uploaded.
How to use it
- Drop a video on the box or click Choose a video. A thumbnail timeline appears under the preview.
- Drag the green start and end handles, or play to a moment and press Set start here / Set end here (keys I and O). Use ←/→ to step one frame and Shift + ←/→ for one second, or type exact times such as
1:23.5. - To cut out sections, set The marked ranges are to Removed and add a range for each part to delete (Add range).
- Choose Lossless (instant, cuts at keyframes) or Exact (re-encodes; optional fade in/out), check the output length, and press Trim video.
- Preview the result and Download it.
Examples
IMG_0123.MOV, 0:42 · Keep 0:03.200–0:39.000 · Lossless
IMG_0123-trimmed.mov from the keyframe nearest 0:03.2 to the one nearest 0:39 — done in seconds, original quality.
lesson.mp4 · Remove the marked parts · Remove 12:05.000–14:40.500 · Exact
lesson-trimmed.mp4, 2 min 35.5 s shorter, joined at exactly those frames.
Keep 1:10–1:40 · Exact · Fade in 1 s · Fade out 1 s
A 30-second clip that fades from and to black, with the sound faded too.
Lossless or exact?
Video is stored as keyframes (complete pictures, usually one every few seconds) followed by frames that only store what changed. A file can only start at a keyframe without re-encoding, so Lossless moves each cut to the nearest keyframe: no quality loss and no waiting, but the cut can be up to a few seconds off. Exact decodes and re-encodes the video, so cuts are frame-accurate and fades are possible; it takes longer and loses a little quality, like any re-encode. The page lists the keyframe-snapped times before you start.
Keyboard shortcuts
These work anywhere in the editor, except in the time boxes and while choosing an option (option buttons and menus use the arrow keys themselves):
- Space — play or pause (on a focused button, Space presses that button)
- ← / → (or , / .) — one frame back or forward; Shift + ← / → — one second
- I / O — set the start / end of the selected range to the playhead
The start and end handles on the timeline are sliders: focus one with Tab and move it with ← / → (one frame), Shift + ← / → (one second), or Home / End (start or end of the video). With the timeline itself focused, Home / End move the playhead to the start or end.
What is kept
The main video track and all audio tracks are kept, with their languages, rotation and metadata (title, date, device). In Lossless mode the codecs and container are untouched; in Exact mode the video is re-encoded with the same codec when this browser can encode it (otherwise H.264, or VP9 for WebM) and the audio is re-encoded too, so it can be cut exactly and faded.
Limitations
- Lossless cuts can only happen at keyframes; if the keyframes are far apart, use Exact mode.
- Exact mode needs WebCodecs (Chrome, Edge, Safari 26+, desktop Firefox 130+) and a decoder for the video’s codec; HEVC needs hardware support in the browser.
- Subtitle tracks, chapters and extra video tracks are not copied.
- The preview uses your browser’s player; if it cannot play the format (for example MKV in Safari), the page shows still frames instead, and if it cannot decode the codec at all only Lossless mode with typed times is available.
- Very long files are held in memory until you download the result unless you use “Save straight to a file” (Chrome/Edge on a computer).
Privacy
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.
Frequently asked questions
Does trimming reduce the quality?
Not in Lossless mode: the kept parts are copied bit for bit. Exact mode re-encodes, which loses a little detail; High quality is used by default.
Why did my lossless cut start a bit earlier or later than I set?
Because a video can only start on a keyframe without re-encoding. The page moves each cut to the nearest keyframe and shows the new times. For a cut on the exact frame, choose Exact.
Can I cut several parts out at once?
Yes. Set The marked ranges are to Removed, add one range per section to delete, and the remaining parts are joined into one file. With Kept you can also keep several separate parts.
Is my video uploaded?
No. The video is cut inside your browser and the new file is created on your device.
Can I trim audio files?
This tool is for video files, so audio formats such as MP3, M4A or WAV are not accepted. A video file that only contains sound (for example an MP4 with no picture) does open, and the cuts then work on the audio.