Google gives every hostname its own allocated crawl budget. So that means each domain, subdomain, etc has its own unique crawl budget.

This was brought up in the comments are in a LinkedIn post where Tony McCreath asked a Google crawl budget questions related to crawling a page on domain A that loads a resource from domain B (different server).

John Mueller from Google responded, saying, “They’re independent.”

Then former Googler, Pedro Dias wrote, “Afaik, it’s allocated set by hostname, right? So, even within the same domain, several subdomains might have their own crawl-rate limits.”

Gary Illyes from Google confirmed this statement to be true, replying, “correct.”

Here is the post:

Want to learn more about crawl budget, see this Google help document.

Forum discussion at LinkedIn.