Is my video uploaded anywhere?

No. The video is read entirely in your browser using the HTML5 File API. Nothing is sent to any server — your file never leaves your device.

How does the tool export the trimmed clip?

It runs ffmpeg.wasm, a WebAssembly build of FFmpeg, inside your browser. The engine (about 32 MB) is downloaded once after you pick a file and then cached. Fast mode copies the audio and video streams without re-encoding, so it finishes in seconds and keeps the original quality and format. Precise mode re-encodes to H.264/AAC MP4 for a frame-exact cut, which takes about as long as the clip or longer for HD and 4K video.

Why does a Fast export start a little before my start time?

Without re-encoding, a clip can only begin on a keyframe, so Fast mode starts at the nearest keyframe before your start point. Phone and camera videos usually have a keyframe every 1 to 2 seconds. The tool tells you when the clip came out longer than selected; choose Precise for a frame-exact start.

Is there a file size limit for exporting in the browser?

The source file is read straight from disk, but the trimmed clip is built in browser memory, so very long clips of large files can fail on phones or low-memory devices. In that case trim a shorter segment or use the FFmpeg command shown on the page.

What does -ss before -i mean in the FFmpeg command?

Placing -ss before the input (-i) uses fast keyframe seeking, which is much faster but may land a few frames off. Placing -ss after -i does frame-accurate seeking but is slower. For most trims the keyframe method is fine; use -accurate_seek before -i for frame-precise cuts.

What is -c copy and when should I change it?

-c copy performs a lossless stream copy — it cuts at keyframes without re-encoding, making it nearly instant and lossless. The trade-off is the cut may not be frame-accurate on non-keyframe boundaries. Replace -c copy with -c:v libx264 -crf 23 for frame-accurate trimming at the cost of a full re-encode.

What video formats are supported for preview?

Browser preview supports formats your browser can decode natively: MP4 (H.264/H.265), WebM (VP8/VP9), and OGG (Theora). MKV, AVI, MOV, and FLV preview depends on browser support. The FFmpeg command works regardless of preview support.

How do I install FFmpeg to run the exported command?

macOS: brew install ffmpeg. Ubuntu/Debian: sudo apt install ffmpeg. Windows: winget install ffmpeg or download from ffmpeg.org/download.html. After install, paste the command shown here directly into your terminal.

Video Trimmer

Set start and end points on any video, preview the clip, and export the trimmed file right in your browser (lossless fast cut or frame-exact MP4), or copy a ready-to-run FFmpeg command.

Drop a video file here

MP4, MOV, MKV, WebM, AVI and more

Load a video file to start trimming.

Prefer the Command Line? FFmpeg Trim Command

Run this in your terminal for very large files. Requires FFmpeg. Follows the mode selected above.

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Summary

Video Trimmer loads a video file locally in your browser, lets you set start and end points with time inputs, the timeline handles or the player position, and previews the exact clip. It then exports the trimmed clip on your device with ffmpeg.wasm: Fast mode copies the streams without re-encoding (original quality, cut at the nearest keyframe), Precise mode re-encodes to an H.264 MP4 for a frame-exact cut. It also generates the matching FFmpeg command for very large files. No file is ever uploaded.

How it works

Drop or browse to select a video file (MP4, MOV, MKV, WebM, AVI, etc.).
The video loads in the browser player and its duration and file info appear.
Drag the timeline handles, type exact times, or pause the player and click Set start / Set end at playhead.
Click "Preview Clip" to play only the selected segment.
Choose Fast (lossless stream copy) or Precise (re-encode to MP4), click "Trim & Export Clip", then download the file.
For very large files, copy the generated FFmpeg command and run it in your terminal instead.

Use cases

Cut the opening or ending of a recorded video before sharing.
Extract a specific scene or highlight clip from a longer video.
Quickly check how long a segment will be before running a full encode.
Get the exact FFmpeg -ss / -to flags without memorizing the syntax.
Preview trim points before committing to an irreversible encode.
Prepare clips for social media by trimming to platform time limits.

Frequently Asked Questions

Last updated: 2026-06-11 · Reviewed by Nham Vu

Video Trimmer

File Info

Trim Points

Export Trimmed Clip

Prefer the Command Line? FFmpeg Trim Command

Summary

How it works

Use cases

Frequently Asked Questions

Video Trimmer

Use the Video Trimmer

File Info

Trim Points

Export Trimmed Clip

Prefer the Command Line? FFmpeg Trim Command

Summary

How it works

Use cases

Frequently Asked Questions