No canonical URL declared
37.2%
of the 3,044 free scans considered in the last 30 days raised this finding. That is 1,131 scans across 1,123 distinct sites. 95% interval 34.4% to 40%.
What it means
A canonical tag tells search engines which address is the real one when a page is reachable under more than one URL.
How to fix it
Add <link rel="canonical" href="https://example.com/this-page"> to the <head> of every page, with the full absolute URL of that page's preferred address.
How to check it yourself
View source and search the head for link rel="canonical". Its absence means no canonical URL is declared.
What fixed looks like
View source shows a canonical tag in the head pointing at the page's own full URL.
How we measured this
Go Voltic scans a site and records which findings it raises. The share above is over every free four-page scan in the last 30 days that loaded at least one page, which is 3,044 scans. Deep scans of paid reports and of the research sweep read a site at a different depth and are a separate population, never in this denominator. It is not a survey and it is not an estimate: it is a count of what our own scanner found. Sites are counted once each in the distinct-sites figure, so a site scanned twice does not weigh double there.
The interval is a 95% Wilson interval. A share printed without its sample size reads as certainty and is indistinguishable from a guess, so both are always shown. Figures on this page were computed on 2026-09-08.
The same share sits beside every other finding on the benchmarks page, which also carries the whole table as CSV and JSON and says how to cite it.
Check your own site
The free scan reads four pages and reports every finding it raises, including this one. It takes about ten seconds and asks for nothing but the address.