Search Engine Optimisation (SEO) involves optimizing a website to improve its ranking on search engine results pages (SERPs). While SEO is multifaceted, a general formula can be structured based on key ranking factors:
SEO Scoring Formula
SEO Score = w1 · C + w2 · B + w4 · U + w5 · E
where:
- C = Content Quality Score
- B = Backlink Score
- T= Technical SEO Score
- U = User Experience Score
- E = Engagement Score
- w1, w2, w3, w4, w5 = Weight coefficients (importance of each factor)
Each of these components can be broken down further.
- Content Quality Score CCC
Content is a primary ranking factor. The formula for content quality could be:
C = k1 · K + k2 · L + k3 · R + k4 · F + k5 · S
where:
- K = Keyword Optimisation (density, placement, synonyms)
- L = Content Length (longer, in-depth content typically ranks higher)
- R = Relevance (semantic relevance to the search query)
- F = Freshness (new or updated content)
- S = Structured Data Usage (schema markup, headings)
Each component is weighted (k1, k2, k3, k4, k5 ) based on importance.
- Backlink Score BBB
Backlinks signal authority and trust. A formula for backlink strength can be:
where:
- Ai = Authority of linking domain (e.g., Moz Domain Authority, Ahrefs DR)
- Ri = Relevance of linking domain to the topic
- Di = Number of outbound links from the linking page
- n = Total number of backlinks
This formula ensures that high-authority, relevant backlinks contribute more than spammy or unrelated ones.
- Technical SEO Score T
Technical SEO ensures search engines can crawl and index content effectively:
T = p1 · S + p2 · M + p3 · P · + p4 · C + p5 · H
where:
- S = Site Speed (Core Web Vitals like LCP, FID, CLS)
- M = Mobile-Friendliness (responsive design, AMP)
- P = Proper Indexing (robots.txt, canonical tags, sitemap)
- C = Security (SSL, HTTPS, safe browsing)
- H = Healthy HTML Structure (valid HTML, structured metadata)
- User Experience Score U
Google prioritises user satisfaction. The UX score is:
U = q1⋅N + q2 ⋅ I + q3⋅D
where:
- N = Navigation Clarity (clear menus, breadcrumbs)
- I = Interactivity & Accessibility (clickable elements, readable fonts)
- D = Dwell Time (how long users stay on the page)
- Engagement Score EEE
Engagement metrics reflect real user behaviour:
E = r1⋅ (1−BR) + r2 ⋅ Tp + r3 ⋅ CR
where:
- BRB_RBR = Bounce Rate (lower is better)
- TPT_PTP = Time on Page
- CRC_RCR = Click-Through Rate (CTR)
Final SEO Score Calculation
SEO Score = w1C + w2B + w3T + w4U + w5E
Each factor is normalised to a scale (e.g., 0 to 100), and the weights w1, w2, w3, w4, w5 are determined based on industry data.
