Video Trimmer

What is a Video Trimmer?

A Video Trimmer lets you cut a video clip to a specific start and end time, removing unwanted footage from the beginning or end — entirely in your browser using FFmpeg WebAssembly. Trimming is the most common video editing task: removing the dead air before a recording starts, cutting off a shaky ending, or extracting a specific scene from a longer video. Because this tool uses FFmpeg compiled to WebAssembly and runs directly in your browser, your video files are never uploaded to any server. The processed video is downloaded directly to your device when trimming is complete.

How to use this tool

1. Click Upload Video to select an MP4, MOV, WebM, or other supported video file from your device.
2. Use the timeline or input fields to set the Start Time and End Time of the segment you want to keep.
3. Preview the selected range in the video player to confirm the trim points look correct.
4. Click Trim Video and wait while FFmpeg processes the file in your browser (may take a moment for large files).
5. Click Download to save the trimmed video to your device.

Common use cases

• Removing the first few seconds of dead air or accidental recording before the main content starts
• Extracting a specific clip from a longer screen recording or gameplay video
• Cutting a video down to a specific duration for social media platforms (Instagram Reels: 90s, TikTok: 60s, etc.)
• Trimming out a mistake or irrelevant section from a presentation recording before sharing it
• Creating a shorter preview or highlight clip from a longer tutorial or webinar

Frequently asked questions

Is my video uploaded to a server?

No — this tool uses FFmpeg compiled to WebAssembly (WASM) and runs entirely within your browser tab. Your video files are never transmitted over the internet. All processing happens locally on your device.

How large a video file can I trim?

There is no hard limit enforced by the tool, but very large files (1 GB+) may exceed your browser's available memory. For best performance, trim files under 500 MB. If you need to process very large files, consider using the desktop version of FFmpeg or a dedicated video editor.

Why does trimming take a long time?

FFmpeg in the browser re-encodes the video by default to ensure clean cut points at any timestamp, which takes time proportional to the file size and duration. Some operations can use 'stream copy' mode (no re-encoding) for faster trimming but this only cuts at keyframe boundaries. The tool uses the most compatible approach for your selected trim points.

What video formats are supported?

This tool supports MP4 (H.264/H.265), WebM (VP8/VP9), MOV, AVI, and most other common video formats that FFmpeg can decode. The output is typically MP4 for broad compatibility. Very exotic or proprietary formats may not decode correctly.