Page Speed SEO Impact Calculator
Score your page's SEO health based on load time, Core Web Vitals, and PageSpeed scores for mobile and desktop. Use it to prioritize performance fixes that will have the greatest impact on rankings.
About this calculator
Google has confirmed page speed and Core Web Vitals as ranking signals, meaning slow pages face measurable ranking penalties. This calculator combines those signals into a single SEO impact score using the formula: Score = max(0, 100 − (loadTime × 10) + (coreWebVitalsScore × 0.3) + (mobilePageSpeed × 0.4) + (desktopPageSpeed × 0.2)) × (industryCompetitiveness × 0.8 + 0.2). Load time has the steepest negative effect: every additional second subtracts 10 points, reflecting research showing that bounce rates rise sharply beyond 3 seconds. Mobile PageSpeed carries the highest positive weight (0.4) because Google uses mobile-first indexing. Core Web Vitals (LCP, FID/INP, CLS) contribute 0.3, rewarding pages with good interactivity and visual stability. The industry-competitiveness multiplier scales the result to reflect that speed matters more in highly contested SERPs where competitors are already optimized.
How to use
Suppose your page loads in 2.5 seconds, has a Core Web Vitals score of 70, a mobile PageSpeed score of 65, a desktop PageSpeed score of 85, and operates in a moderately competitive industry (competitiveness = 1.0). 1. Load penalty: 100 − (2.5 × 10) = 100 − 25 = 75 2. Add CWV: 75 + (70 × 0.3) = 75 + 21 = 96 3. Add mobile: 96 + (65 × 0.4) = 96 + 26 = 122 4. Add desktop: 122 + (85 × 0.2) = 122 + 17 = 139 5. Industry multiplier: 139 × (1.0 × 0.8 + 0.2) = 139 × 1.0 = 139 → max(0, 139) = 139 Note: scores above 100 indicate strong performance. Reducing load time to 1.5s would raise the base by 10 additional points.
Frequently asked questions
How much does page load time actually affect Google search rankings?
Google has explicitly included page speed in its ranking algorithm since 2010 for desktop and 2018 for mobile. More recently, Core Web Vitals became a confirmed ranking signal in the Page Experience update. Research from industry studies consistently shows that pages loading in under 2 seconds rank significantly higher on average than pages taking 4+ seconds. In this calculator, each additional second of load time deducts 10 points from the base score, which is a deliberate modeling of speed's outsized negative impact relative to other factors. Shaving even one second off a slow page can meaningfully improve both rankings and user-driven engagement metrics like bounce rate.
Why does mobile PageSpeed score carry more weight than desktop in the SEO impact formula?
Google switched to mobile-first indexing in 2019, meaning it predominantly uses the mobile version of your content for indexing and ranking purposes. As a result, poor mobile performance has a more direct and immediate impact on rankings than equivalent desktop performance issues. The formula reflects this by weighting mobile PageSpeed at 0.4 versus desktop at 0.2 — mobile issues penalize your SEO impact score twice as much. If you can only optimize one version of a page, the mobile experience should always take priority.
What are Core Web Vitals and why do they matter for SEO scoring?
Core Web Vitals are three user-experience metrics defined by Google: Largest Contentful Paint (LCP) measures loading performance, Interaction to Next Paint (INP) measures responsiveness, and Cumulative Layout Shift (CLS) measures visual stability. Google incorporated them as ranking signals in its Page Experience update because they quantify real-world usability, not just raw speed. Pages that pass the Core Web Vitals thresholds (LCP < 2.5s, INP < 200ms, CLS < 0.1) receive a positive ranking boost. In this calculator, a higher Core Web Vitals score increases your overall SEO impact score, reflecting Google's emphasis on these metrics as a quality signal beyond traditional speed metrics.