Video Trimmer
Cut videos to the exact length you need. Fast mode trims instantly, precise mode cuts frame by frame.
Drop your video here
or click to browse
Two ways to cut
This has a fast mode and a precise mode, and the difference matters more than it sounds.
Fast mode copies the existing streams without re-encoding. It is close to instantaneous even on a large file and the quality is bit-for-bit identical to the source, because nothing is decoded or re-compressed. The catch is that it can only cut on a keyframe, so your actual start point snaps to the nearest one before the mark you set. On a typical recording that is within a second or two; on footage with sparse keyframes it can be further.
Precise mode re-encodes with H.264 at -crf 23 and the fast x264 preset, so the cut lands exactly where you put it. That costs time and a generation of quality loss.
Settings and limits
- Max input500 MB
- Core25 MB, once
- Threads1
More detail
Which one to use
Start with fast mode. Most of the time a keyframe-aligned cut is fine, and you keep the original quality for free.
Switch to precise when the exact frame matters: cutting mid-sentence, clipping a specific moment, or stitching the result into something else where a stray second at the front would show.
Things worth knowing
Everything runs in your browser through ffmpeg compiled to WebAssembly. Nothing is uploaded. The core is about 25 MB and is fetched once per session, so the first operation is slower than the ones after it.
Precise mode is single-threaded, so a long clip takes real time. Fast mode barely cares how long the video is, because it is essentially a copy.
Input is capped at 500 MB, though the browser's memory ceiling usually bites first on large 4K sources.
Both modes write an .mp4 with faststart set, so the result can begin playing before it has fully downloaded if you host it somewhere.
Questions
Is the video uploaded?
No. The trim happens in your browser. The only network request is the initial fetch of the ffmpeg core from a CDN.
Why did my cut start a second earlier than I set it?
That is fast mode snapping to the nearest keyframe. Stream copying cannot start mid-GOP, so it backs up to the last keyframe before your mark. Switch to precise mode if you need the exact frame.
Does trimming reduce quality?
Not in fast mode. It copies the existing streams untouched, so the output is identical to the source within the range you kept. Precise mode re-encodes, which costs one generation of quality.
Can I cut out a section from the middle?
Not in one pass. This keeps one continuous range. To remove a middle section you would trim twice and join the results, which this tool does not do.