Does a canonical tag stop Google from repeatedly crawling parameter URLs, or only consolidate them?

A canonical tag mainly consolidates duplicate URLs; it doesn’t guarantee Google will never request the parameter versions again. Google may still crawl a parameter URL to discover it, evaluate the canonical, and pick up changes. The preferred URL is the one Google can show and group signals under, while duplicate versions may be crawled less often—but that isn’t the same as being blocked.

If parameter URLs are burning crawl activity, first make internal links and sitemaps use the clean URL, and keep the canonical consistent. For genuinely useless or effectively endless parameter patterns, Google also recommends blocking problematic dynamic URLs in robots.txt. Just don’t use robots.txt as a canonicalization shortcut: Google can’t fetch a blocked URL to see its canonical tag. Think of canonical as consolidation; reduce the source of the extra URLs or use a crawl-control rule when you need fewer crawls.