Video Trimmer
Cut video without re-encoding, or frame-exact, in your browser. Runs in your browser.
About this video trimmer
This video trimmer cuts the start, the end or any middle part out of an MP4, MOV, WebM or MKV file. Fast mode copies the original video data, so it takes seconds and loses no quality. Exact mode re-encodes, so every cut lands on the frame you chose.
The video stays on your device. Nothing is uploaded, there is no watermark and no account, and a 2 GB file opens as quickly as a small one.
Keep one part or several. Several segments can be joined into one file, or saved as separate files, which is how you cut the boring middle out of a clip or split a long recording into chapters. Mute is one checkbox.
Features
Fast cuts with no re-encode
Fast mode copies the compressed frames as they are, like a lossless cut in a desktop editor. Quality is identical to the original and it works in every browser, even without WebCodecs.
Frame-exact cuts
Exact mode decodes the range and re-encodes it with your browser's encoder at about the source bitrate. Use −1 frame and +1 frame to land on the precise frame.
Thumbnail timeline
A strip of frames across the whole video shows where scenes change. Keyframes are marked in Fast mode, so you can see where a fast cut will start.
Several segments
Add segments, split one at the playhead, and see each in its own color on the timeline. Overlapping segments are merged when joining so nothing plays twice.
Join or save separately
Join the kept parts into one file, or download each one as name-part1, name-part2 and so on, singly or in a ZIP.
Exact times and keyboard nudges
Type 1:15.25, 75.25 or 1m15s. On the yellow handles, ←/→ moves 0.1 s and Shift+←/→ moves a full second. In the time boxes ↑/↓ do the same.
How to use the video trimmer
- 1Add a video, then drag the yellow handles or type exact start and end times.
- 2Add more segments if you want, and choose Fast (no re-encode) or Exact (frame-accurate) mode.
- 3Join the segments into one file or save each one, with or without sound, and download.
When to use it
Cut the dead air off a recording
Meetings, lectures and screen recordings often start with a minute of setup. Fast mode removes it from a long file in seconds.
Remove a middle section
Split at the start of the part you don't want, set the second segment to begin after it, and join. The output skips the gap.
Clip a moment to share
Trim a 10-second highlight, then compress it to fit a chat upload limit or turn it into a GIF.
Split a long video into parts
Mark each chapter as a segment, choose Separate files and download a ZIP. Fast mode keeps every part at the original quality.
How do I trim a video without losing quality?
Use Fast mode. Compressed video stores a full picture only now and then, at keyframes (I-frames). The frames in between store just the changes from earlier frames. A cut that copies data without re-encoding has to begin on a keyframe, or the first frames would have nothing to build on.
So a fast cut starts at the keyframe at or before your start time. In MP4 and MOV single cuts, those extra frames are kept but hidden with an edit list, which most players respect, so playback begins right on your mark. In WebM, MKV and joined files the clip simply starts a little early. The tool shows exactly where.
How far apart are keyframes?
It depends on the encoder. YouTube recommends a keyframe every half second for uploads (a closed GOP of half the frame rate). Phone cameras and screen recorders often use around 1 to 2 seconds, and live-streaming encoders 2 to 5. The tool reads the actual keyframes in your file and shows the average gap in the Fast mode note.
If the gap is small, Fast mode is close enough for nearly everything. If it is several seconds and your cut must be precise, use Exact mode.
Fast vs Exact: which should I pick?
Pick Fast for long files, for anything you'll edit again later, and whenever starting a fraction of a second early doesn't matter. It is the only mode that keeps the original quality.
Pick Exact when the first frame matters, for example a clip that must start on a specific word or beat. It re-encodes to H.264 MP4 where your browser supports it, otherwise VP9 WebM. That is a second round of compression, so quality drops slightly and it takes about as long as compressing the clip.
- Fast: original quality, seconds for any size, starts on a keyframe, works without WebCodecs.
- Exact: frame-accurate, needs WebCodecs video encoding, slower, small quality loss.
What's the difference between trimming, cutting and splitting?
Trimming removes the beginning or end. Cutting removes a section from the middle and joins what's left. Splitting divides one video into several files. This tool does all three with segments: one segment trims, two or more joined segments cut out the gaps, and Separate files splits.
Why use Mavros
| Mavros | Typical upload sites | |
|---|---|---|
| Upload required | No, runs on your device | Yes, the whole video |
| Lossless (no re-encode) cuts | Yes, Fast mode | Rarely explained or offered |
| Frame-accurate cuts | Yes, Exact mode | Usually to the second |
| Multiple segments | Join or save separately | Join only, or a full editor |
| Mute | Built in | Often a separate tool |
| Watermark or sign-up | Neither | Common on free plans |
| File size limit | Your device's memory | 500 MB to 4 GB |
Tips
- Click anywhere on the thumbnail strip to move the playhead, then use Start here and End here.
- Fast mode output keeps the original container, so a MOV stays a MOV. Exact mode writes MP4 or WebM.
- Mute removes the audio track entirely rather than writing silence, so the file gets a little smaller too.
- Trimming never changes your original file. You download a new copy named like holiday-trimmed.mp4.
- Only want the sound from part of a video? Save just the soundtrack as an MP3 with its own trim range.
Questions
Does trimming a video reduce quality?
Not in Fast mode, which copies the original data unchanged. Exact mode re-encodes the video, which costs a small amount of quality in exchange for frame-accurate cuts.
Why does my fast cut start a little before the time I set?
A cut without re-encoding must start on a keyframe, and your start time fell between two. The clip begins at the keyframe before it. Switch to Exact mode for a frame-accurate start.
How do I cut out the middle of a video?
Make two segments: one ending where the unwanted part begins, one starting where it ends. Choose Join into one file and export. Split at the playhead makes the first step quick.
Is my video uploaded?
No. The file is read and written in your browser, so it never leaves your device. That's also why large files work without a long upload.
Does it change my original file?
No. The trimmed video is a new file you download. Your original stays exactly as it was.
Which formats can I trim?
MP4, MOV, WebM and MKV with common codecs such as H.264, HEVC, VP9 and AV1. Fast mode works even when your browser can't play the codec. Exact mode needs to decode it, so HEVC requires hardware support.
Can I save the trimmed video in another format?
Exact mode always writes MP4 (H.264) or WebM, so a MOV or MKV becomes MP4. Fast mode keeps the original format.
Does it work on a phone?
Yes, in current Chrome on Android and Safari on iPhone. Fast mode is quick even on phones; Exact mode depends on the phone's video encoder.