How to Cut and Trim MP4 Video Online — Free, No Upload, No Watermark
Need to shorten a video or cut out a segment without installing software or uploading your file to a stranger's server? Here's how to do it in your browser — in seconds for most files, with no watermark, no account, and no size limit.
Quick Answer
Use the Trim Media tool — drag your video in, set a start and end time, and download the cut. Choose Fast mode for near-instant results on any file size, or Precise mode for frame-accurate cuts. No upload, no watermark, no account.
Trim Video Free →Fast Trim vs Precise Trim — Which Should You Use?
The tool offers two modes because video files store frames in a way that makes truly arbitrary cuts technically different from "close enough" cuts. Here's the practical difference:
Fast Mode (Keyframe Copy)
- Speed: Near-instant, even for 2 GB files
- Quality: Zero re-compression — original bitrate preserved exactly
- Accuracy: Cut snaps to the nearest keyframe, which may be up to ~0.5 seconds from your target time
- Best for: Removing a large chunk from the beginning or end of a video, splitting a recording into sections
✅ Use this for most trimming tasks
Precise Mode (Re-encode)
- Speed: Slower — FFmpeg re-encodes every frame in the output
- Quality: Slight quality reduction from re-encoding (usually imperceptible)
- Accuracy: Frame-accurate — cuts exactly at the timestamp you typed
- Best for: Clipping a specific moment (e.g. a 3-second clip for social media), removing a mid-video segment where timing matters
✅ Use this when the exact cut point matters
Why the difference exists: Video is compressed by storing only the changes between frames. A "keyframe" is a full snapshot; everything between keyframes is encoded as deltas. Cutting at a non-keyframe position in Fast mode would produce corrupted frames, so FFmpeg snaps to the nearest safe cut point. Precise mode avoids this by decoding and re-encoding the boundary frames fresh.
Step by Step: Cut an MP4 in Your Browser
- 1
Open the video trimmer and load your file
Go to the Trim Media tool and drag your video or audio file onto the page, or click to browse. The file is loaded entirely in your browser — nothing is sent to any server.
- 2
Choose Fast or Precise mode
Fast mode copies the video stream without re-encoding — it is near-instant even for very large files, but the cut may be up to one keyframe (~0.5 seconds) away from your exact target. Precise mode re-encodes the output for frame-accurate cuts, which takes longer but gives you exactly the timestamp you entered.
- 3
Set your start and end timestamps
Drag the handles on the timeline, or type exact times in HH:MM:SS.s format (e.g. 00:01:23.5 for one minute, twenty-three and a half seconds). The preview updates so you can verify the segment before trimming.
- 4
Click Trim and download the result
FFmpeg processes the segment in your browser. When it finishes, click Download to save your trimmed MP4 or audio file. The output retains the original quality — no re-compression in Fast mode.
How to Type Exact Timestamps
The timestamp fields accept the format HH:MM:SS.s — hours, minutes, seconds, and an optional decimal for sub-second precision.
00:00:3030 seconds in00:01:23.51 minute, 23.5 seconds in01:05:001 hour, 5 minutes in00:00:00Beginning of file (default start)Tip: Drag the timeline handles first to get close, then type the exact value into the timestamp field to fine-tune. In Precise mode, the sub-second decimal (.s) is honored precisely — useful for cutting at a word boundary in speech or a beat in music.
What File Formats Are Supported?
The tool handles both video and audio files — whatever FFmpeg can decode, which covers virtually every mainstream format:
Video Formats
Audio Formats
Fast mode preserves the original codec. Precise mode outputs MP4 (H.264/AAC) for video inputs and MP3 for audio inputs.
FAQ
Does it add a watermark?
No. The output file is a clean, unbranded MP4 or MP3. No watermarks, no logos, no overlay text — just the trimmed segment you asked for. This applies to both Fast mode and Precise mode.
Is there a file size limit?
There is no hard limit imposed by the tool. Very large files (over 2 GB) may exhaust available browser memory on lower-end devices. Fast mode (keyframe copy) is especially memory-efficient because it copies the compressed video stream without decoding every frame — making it the better choice for large files.
Can I trim audio files too?
Yes. The tool handles MP3, WAV, M4A, AAC, OGG, and FLAC in addition to video formats. Drop an audio file, set your start and end times, and download the trimmed audio. Precise mode outputs MP3 for audio inputs; Fast mode copies the original audio codec.
What is SharedArrayBuffer and why does FFmpeg need it?
FFmpeg WebAssembly uses multi-threading to speed up processing. Multi-threading in browsers requires SharedArrayBuffer, which in turn requires the page to be served with Cross-Origin-Opener-Policy (COOP) and Cross-Origin-Embedder-Policy (COEP) headers. This site has those headers enabled. If you see a browser compatibility warning, try Chrome or Firefox on desktop — both support SharedArrayBuffer fully.
Can I cut multiple videos at once?
Currently the tool processes one file at a time. After your file finishes, you can load the next one. Batch trimming with different start/end times per file is on the roadmap.