YappyKit

Compress a video to fit a limit

Fit a video under WhatsApp, email or a size limit, compressed in this browser tab and never uploaded.

How it works

Messaging apps and email impose size limits, and a phone video often sails past them. This tool shrinks a video to fit a limit you choose (WhatsApp, email, or a custom size) rather than making you guess a bitrate.

It reads the video’s length, calculates the bitrate that fits your target, and re-encodes to MP4 (H.264 video, AAC audio) using a video engine that runs entirely in your browser. The first time you compress, that engine (about 30 MB) downloads and is then cached for next time. Your video is never uploaded.

Because quality has a floor, a very small target on a long video may not be fully reachable: the tool tells you when that happens instead of producing something unwatchable.

How to use it

  1. 1 Choose your video (MP4, MOV or WebM).
  2. 2 Pick a target size, WhatsApp, email, or under 10 MB.
  3. 3 Press Compress. The first run downloads the video engine (~30 MB).
  4. 4 Download the compressed MP4.

Good to know

  • The first compression downloads the engine once; after that it works offline.
  • Very small targets on long videos may not be fully reachable, quality has a floor.
  • Output is an MP4 (H.264 / AAC) that plays almost everywhere.
  • Your video is never uploaded. It is compressed in your browser.

Frequently asked questions

How do I make a video small enough to send on WhatsApp?

Pick the “WhatsApp (16 MB)” target, choose your video, and press Compress. The output is an MP4 that fits.

Why does the first compression take a while to start?

The first run downloads the ~30 MB video engine. It is cached afterwards, so later compressions start immediately and work offline.

Is my video uploaded to a server?

No. The whole compression runs inside your browser tab.

Why can’t a long video reach a very small size?

Below a minimum bitrate the video becomes unwatchable, so very small targets on long videos may not be reachable; the tool compresses as far as sensible and tells you.

Which video formats are supported?

Common inputs like MP4, MOV and WebM. The output is an MP4.

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Your files are processed on your device and are not uploaded. You can verify this in your browser’s developer tools under the Network tab.