Compress Videos Without Uploading
Reduce video file size using FFmpeg running directly in your browser. Your files never leave your device — 100% private, no sign-up, always free.
Why Use VidShrink?
100% Private
FFmpeg runs in your browser via WebAssembly. Your video never leaves your device — no server, no cloud storage, no logs.
Powered by FFmpeg
Uses the same FFmpeg engine trusted by professionals — compiled to WebAssembly and run locally for real compression results.
Quality Presets
Choose from High, Medium, or Low quality presets, or set a custom CRF value for precise control over the size/quality tradeoff.
Size Comparison
See the original and compressed file sizes side-by-side with the exact reduction percentage before downloading.
Multiple Formats
Supports MP4, MOV, AVI, MKV, and WebM as input. Output is always MP4 (H.264 + AAC) for maximum compatibility.
Works Everywhere
Fully responsive on desktop and mobile. Works in Chrome, Edge, Firefox, and Safari on any operating system.
Video Compressor
Drop your video here
or click to browse — MP4, MOV, AVI, MKV, WebM
Downloading FFmpeg engine (~30 MB)…
How to Compress a Video
Upload Your Video
Drag and drop or click to select a video file. Supports MP4, MOV, AVI, MKV, and WebM formats.
Choose Quality
Select a preset — High keeps quality close to original, Medium is a good balance, Low gives the smallest file size.
Download
Click Compress and wait for FFmpeg to process your video in the browser. Download the result when done.
Frequently Asked Questions
Is my video uploaded to a server?
No. VidShrink uses FFmpeg compiled to WebAssembly, which runs entirely in your browser. Your video file never leaves your device and is not sent to any server.
Why does it need to download ~30 MB on first use?
FFmpeg is a powerful video processing engine. The WebAssembly version weighs about 30 MB. It's only downloaded once — after that it's cached in your browser for instant future use.
What is CRF and how does it work?
CRF (Constant Rate Factor) controls quality vs. file size. Lower values = higher quality and larger file. Higher values = smaller file with more compression artifacts. The range is 0 (lossless) to 51 (worst). CRF 20–28 is ideal for most use cases.
What video formats are supported?
Input: MP4, MOV, AVI, MKV, WebM, and most other common video formats. Output is always MP4 (H.264 video + AAC audio), which is compatible with virtually all devices and platforms.
How much can it compress a video?
It depends on the source video. A typical screen recording or phone video can be reduced by 40–70%. Already-compressed videos will see less reduction. The Medium preset (CRF 28) is a good starting point.