Calculate HTTP header overhead across a page load and the saving from compression.
Headers are sent on every request, so a large cookie multiplies across the whole page load and consumes scarce uplink bandwidth. HTTP/2 header compression removes most of the repetition. Cookies on static asset domains are pure waste, which is why serving assets from a cookieless domain was standard practice before HTTP/2.
HTTP Header Size
Header overhead = requests × (request + cookie + response header bytes)
Header overhead = requests × (request + cookie + response header bytes) Headers are sent on every request, so a large cookie multiplies across the whole page load and consumes scarce uplink bandwidth. HTTP/2 header compression removes most of the repetition.
Cookies on static asset domains are pure waste, which is why serving assets from a cookieless domain was standard practice before HTTP/2.
This calculator takes 5 inputs: Requests per page load, Average request header size, Average response header size, Cookie size sent per request, Saving from HTTP/2 header compression. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.