Does trimming reduce video quality?

We use stream copy mode (-c copy) which cuts the video without re-encoding, preserving the original quality.

What is the maximum file size?

There is no strict limit — all processing is done locally in your browser. Very large files (>1GB) may take more time and memory.

How long a video can I trim?

There is no fixed limit, but the whole file is processed in your browser's memory, so very large videos are bound by available RAM. A keyframe (stream-copy) cut handles multi-gigabyte files easily, while a full re-encode of a long 4K clip is far more memory- and CPU-intensive on a phone than on a laptop.

Why isn't my cut exactly on the frame I chose?

A fast keyframe cut snaps to the nearest keyframe, which can be a second or two from your target. For frame-accurate cuts choose the re-encode mode — it decodes and re-encodes so the clip starts on the exact frame, at the cost of extra processing time.

Does the trimmed clip keep the audio?

Yes. The audio track is preserved and stays in sync with the trimmed video. With stream-copy, subtitle and chapter metadata embedded in the source are retained too, keeping your clip self-contained.

Will trimming re-compress my video?

Not in keyframe (stream-copy) mode — the existing video data is copied untouched, so there is zero generation loss and it finishes almost instantly. Only the re-encode mode re-compresses, which you choose when you need exact frame accuracy or a format change.

Can I trim vertical or 4K videos?

Yes. Resolution and orientation do not restrict trimming; MP4, WebM, MOV and MKV in any resolution work. Keep in mind a 4K re-encode uses far more memory and CPU in the browser than 1080p, so a stream-copy cut is the faster choice for large files.

Video Trimmer — Cut Videos Online Free

How to use Video Trimmer & Cutter

The Video Trimmer lets you cut any portion of an MP4, WebM, MOV or MKV video by setting a precise start time and end time, then exports the clipped segment — entirely in your browser without uploading the file to any server. Ideal for removing intros and outros, isolating a highlight clip, or shortening a screen recording before sharing.

Click "Select Video" and open your video file (MP4, WebM, MOV or MKV).
Use the timeline scrubber or type exact timestamps to set the start and end of the clip.
Preview the trimmed segment using the built-in player to confirm the cut points.
Choose whether to re-encode the clip or perform a fast keyframe-accurate cut.
Click Trim, then download the exported clip when processing completes.

Your data never leaves your device — 100% private processing.

Re-encode vs keyframe cut

A keyframe (stream-copy) cut is nearly instantaneous because the video data is not decoded and re-encoded — the tool simply finds the nearest keyframe to your chosen timestamp and copies the stream. The trade-off is that the actual cut point may be slightly off from your target. A full re-encode is slower but delivers frame-accurate cuts and lets you change the output format or resolution at the same time. For most social-media clips, a keyframe cut is the faster, practical choice.

Trim method comparison
Method	Speed	Frame accuracy	Output size
Keyframe cut	Very fast	Near the keyframe	Same as source
Full re-encode	Slower	Exact frame	Depends on codec

Supported video formats for trimming

The trimmer accepts the most widely used video containers: MP4 (H.264/H.265), WebM (VP8/VP9/AV1), MOV (QuickTime) and MKV (Matroska). Audio tracks are preserved in the output. Subtitle and chapter metadata embedded in the source file are also retained when you use the stream-copy method, keeping your clip self-contained.

Glossary

Keyframe: A fully encoded video frame used as a reference; frames between keyframes store only the difference from the nearest keyframe.
Stream copy: Copying audio or video data from source to output without decoding or re-encoding, which is extremely fast.
Re-encode: Fully decoding compressed media and compressing it again, which is slower but allows precise cuts and format changes.
Timestamp: A position in a media file expressed as HH:MM:SS.mmm, used to specify start and end points for trimming.
GOP (Group of Pictures): A sequence of frames between two keyframes; the length of the GOP determines how close a keyframe cut can be to a target time.

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Video Trimmer & Cutter

How to use Video Trimmer & Cutter

Re-encode vs keyframe cut

Supported video formats for trimming

Glossary

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