SEO health score

How the score is calculated

Each tool computes it differently, so scores are not comparable across platforms. Ahrefs Site Audit defines Health Score as the “proportion of internal URLs crawled by Site Audit that don’t have errors,” literally (URLs without errors / total internal URLs) x 100. Only red “error” issues drag it down. Warnings and notices are excluded. Ahrefs bands it 0-30 weak, 31-70 fair, 71-90 good, 91-100 excellent. Semrush’s Site Health Score weighs both errors and warnings (notices count for less) against the number of checks run, with errors carrying more weight.

Because the math differs, a 78 in Ahrefs and a 78 in Semrush do not mean the same thing. Neither number is something Google publishes or uses. Both are internal to the tool, so treat the score as a triage dial, not a grade. A 5,000-page site can post a strong 92 while hiding a single error type that blocks an important template from indexing. A tiny site can read 60 because two of its ten pages return a 4xx. Always open up which issues moved the number rather than chasing the number itself, and read it alongside indexation, Core Web Vitals, and actual rankings.