WhatsApp enforces a 16MB file size limit on video attachments for most accounts. Some business and premium accounts get up to 64MB, but the standard limit for the vast majority of users worldwide is 16MB. A single 30-second 1080p video recorded on a modern smartphone typically weighs 50-80MB. That means you need to compress it by roughly 75-80% to get it under the limit.
Why WhatsApp's built-in compression is not enough
WhatsApp does compress videos automatically when you send them, but the results are often terrible. The app applies aggressive compression with no user control, frequently producing pixelated, blurry output. Worse, if the original file is too large, WhatsApp may refuse to send it entirely or silently fail on slower connections. The better approach is to compress the video yourself before sending it, so you control the quality-to-size tradeoff.
The settings that matter for WhatsApp
For WhatsApp, there are three levers you can pull to shrink a video file:
Resolution is the biggest factor. WhatsApp videos are watched on phone screens, which are typically 6-7 inches. At that viewing size, there is no visible difference between 1080p and 720p. Dropping from 1080p to 720p cuts the pixel count by more than half, immediately producing a much smaller file. For very long videos, 480p is also acceptable on mobile and produces even smaller files.
CRF (Constant Rate Factor) is the quality slider. For WhatsApp, a CRF of 28-32 is the sweet spot. CRF 28 looks good on a phone screen and produces files roughly 60-70% smaller than the original. CRF 32 compresses more aggressively and is suitable for videos where fine detail does not matter, like talking-head clips or screen recordings.
Codec choice also matters. H.264 is the safest codec for WhatsApp compatibility across all devices, including older Android phones. H.265 produces smaller files at the same quality but may not play correctly on all recipient devices.
A concrete example
A 60-second 1080p video recorded on an iPhone typically weighs 120-180MB in HEVC. Compressing it to 720p with H.264 at CRF 28 produces a file around 8-12MB, well under WhatsApp's 16MB limit. The visual quality on a phone screen is indistinguishable from the original for most content.
How to compress for WhatsApp in your browser
The MediaBrew video compressor has a dedicated WhatsApp preset. Upload your video, select the WhatsApp preset, and the tool automatically applies 1280px max width, H.264 encoding, and CRF 28. The entire process runs locally in your browser using WebAssembly. Your video is never uploaded to any server, which also means it works offline once the page has loaded.
If the result is still over 16MB, try trimming the video to a shorter duration first, or switch to a more aggressive CRF value using the custom slider.