Compress Video

Shrink big video files with a simple quality preset. Free, private, and your files never leave your device.

Drop a video here or click to choose

Supported input: MP4, MOV, MKV, WEBM, AVI

High1080p · CRF 23 · best quality
Medium720p · CRF 28 · balanced
Small480p · CRF 32 · smallest file
Loading the video engine — first time only. This downloads roughly 32 MB and is cached afterwards.
Original: —
Compressed: —
Saved: —

How to compress a video

  1. Drop a video (MP4, MOV, MKV, WEBM or AVI) into the box above, or click to browse.
  2. Pick a quality preset: High (1080p), Medium (720p) or Small (480p).
  3. Click Compress video. The first run downloads the engine (about 32 MB, cached for next time).
  4. Watch the progress bar and see the before and after file sizes when it finishes.
  5. Click Download compressed video to save the smaller file.

Why use ZillaKit's Compress Video tool?

Compression runs entirely inside your browser using a WebAssembly build of FFmpeg, so your footage is never uploaded to a server and never leaves your device. That is a real privacy win over the many online compressors that push your video into their cloud before they do anything. Each preset re-encodes to efficient H.264 video and AAC audio, scaling the resolution and setting a constant rate factor so you can trade a little visual quality for a much smaller file. High keeps up to 1080p for sharing without a big quality hit, Medium targets 720p for email and messaging apps, and Small drops to 480p when you need the tiniest possible file. There is no signup, no watermark and no email required, and it is free with a generous daily allowance. Because everything is local, the speed depends on your own device rather than a shared server, so larger clips take longer but stay completely private.

FAQ

Is my video uploaded anywhere?

No. All compression happens locally in your browser using FFmpeg compiled to WebAssembly. Your video never leaves your device.

Which codecs are used?

Every preset encodes to H.264 video and AAC audio in an MP4 container, which plays almost everywhere including phones, browsers and social platforms.

How much smaller will my file be?

It depends on the source, but lowering the resolution and raising the CRF value usually cuts size dramatically. The tool shows the exact before and after sizes so you can see the saving.

Why does the first compression take a moment to start?

The first run downloads the video engine, roughly 32 MB. Your browser caches it, so every compression after that starts much faster.

How large a file can I compress?

Because everything runs in a browser tab, very large files can exhaust available memory. We suggest keeping videos under about 500 MB, and using a desktop browser for the biggest files.