No upload, 100% local, no account

Trim video

Select start and end times to cut your video. Fast mode cuts near keyframes (instant), precise mode re-encodes for frame-accurate results.

How Trim video works

Cut a video to any start and end time with ffmpeg WebAssembly. Choose fast stream copy for an instant, lossless cut when frame-perfect precision is not critical, or switch to re-encode mode for exact frame-accurate trimming at the cost of extra processing time.

Speed scales with your hardware and the file size. Copy mode finishes in seconds regardless of clip length; re-encode mode processes the selected segment in real time, so a two-minute excerpt from a large file may take a minute or two on a mid-range device.

Frequently asked questions

Are my files uploaded to a server?

No. ffmpeg compiled to WebAssembly trims your video right here in this browser tab, your footage is read into memory on your own device, the selected range is cut there (in Fast mode by stream-copying with -c copy, no re-encode; in Precise mode by re-encoding with libx264), and the trimmed clip is offered as a local download. Nothing reaches Sunasty or any third party. Open your browser's DevTools, go to the Network tab and watch: no request carries your video.

What is the difference between stream copy and re-encode for trimming?

Stream copy seeks to the nearest keyframe before your chosen start point and cuts at the nearest keyframe after your end point, it is very fast and produces no quality loss, but the actual cut may be off by a fraction of a second. Re-encode mode transcodes the segment precisely to your chosen timestamps, giving frame-perfect accuracy at the expense of processing time and a minor quality trade-off.

What video formats can I trim?

Any format ffmpeg supports: MP4, MOV, WebM, MKV, AVI, and many more. The output defaults to MP4 (H.264), which plays universally. If you trim a WebM source in copy mode, the output stays WebM to avoid a forced re-encode.

Does it work offline?

Yes, once the page and the ffmpeg engine have loaded. The engine downloads on first use and is sizeable, but once cached it runs entirely on your device, no internet needed to trim a video.

Is it free? Do I need an account?

It is completely free and requires no sign-up. There are no watermarks, no daily limits and no tracking cookies needed to use the tool.