Shrink MP4, MOV, WebM and MKV videos up to 80% — right in your browser, in seconds. Powered by WebCodecs, with a live size preview and a synced before/after compare. No upload, no signup.
Drop a video or click to browse
MP4, MOV, WebM, MKV, AVI — shrink files by up to 80%
100% in your browser — your video never leaves your device · up to 500 MB
Drop your video
Drag and drop an MP4, MOV, WebM, MKV or AVI file — up to 500 MB on desktop. It stays on your device.
Pick a quality and size
Choose High, Balanced, or Small. If your clip is 4K, keep the one-tap 'Downscale to 1080p' on to save around 75%. See the estimated size update live.
Compress and compare
Encoding runs locally via WebCodecs. Play the synced before/after preview, then download your MP4.
Going to WhatsApp or email? Pick Balanced + Downscale to 1080p — it usually lands well under the 16-25 MB limits while still looking sharp. Convert a GIF instead
Most compressors re-encode with FFmpeg in WebAssembly — slow. omnikitbolt uses your browser's native, hardware-accelerated WebCodecs encoder, so a 2-minute 1080p clip finishes in seconds.
The whole compression runs on your device. Your video is never sent to a server — true privacy for personal clips, work footage, or anything confidential.
A live estimated size, a one-tap 'downscale to 1080p' that saves ~75%, and a synchronized before/after player so you can judge quality at the exact same frame.
Most "free online video compressors" upload your file to a server, re-encode it there, and hand you a download link. That means your footage leaves your device, sits in someone else's cloud, and you wait on their queue. omnikitbolt does the entire job locally: it reads the video, re-encodes it with your browser's built-in video encoder, and writes a new MP4 — all without a single byte being uploaded.
Older browser compressors ship FFmpeg compiled to WebAssembly. It works, but it runs on the CPU with no access to your device's video hardware, so a short clip can take minutes. omnikitbolt uses the modern WebCodecs API, which taps the same hardware encoder your phone and laptop use to record video. In controlled tests that difference is roughly 15x — the gap between waiting two minutes and waiting a few seconds.
A 4K video has four times the pixels of 1080p. For most uses — messaging, email, social, embedding on a site — 1080p is indistinguishable on the screens people actually watch on, and it cuts the file by around 75% before any quality compression even kicks in. That's why omnikitbolt offers a one-tap "Downscale to 1080p" and turns it on automatically for 4K sources.
You control that. "High" keeps the result near-identical to the source; "Balanced" is the sweet spot most people want; "Small" pushes for the lightest file. The synchronized before/after player lets you scrub both clips to the same frame and judge for yourself before downloading. Audio is copied through untouched whenever possible, so the sound stays exactly as recorded.
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