For Google Search, the term crawl budget refers to the number of pages that Googlebot crawls within a given time frame.
Google’s John Mueller has often said that Googlebot doesn’t necessarily crawl all pages of a site.
Also, as we’ll find out below, Googlebot and Google AdsBot share the same crawl budget.
During the December 10th, 2021 Google SEO Office-Hours, at roughly the 8-minute 49-second mark, John Mueller was asked about the crawl budget.
(The video below has been queued to the proper time.)
During a series of questions, a participant asked:
So also about Googlebot: does AdsBot share the same crawl budget with Googlebot?
John’s response was: “Yes.”
The participant responded:
“Yes, so that means that maybe, if the Chrome requests from AdsBot increase, then maybe Googlebot crawls less?”
“Yes, it can happen. Usually it settles down fairly quickly. Again, I don't know the details from the ad side, but my understanding is when you submit new Ads campaigns, then the AdsBot checks all of those pages.
“And once that's checked then they don't need to be checked as often as usual.”
The participant went on to ask a couple of more questions, and you can listen to the video above to learn more.
In conclusion, Googlebot and AdsBot share the same crawl budget.