Why Core Web Vitals Matter
Since 2021, Google has officially factored Core Web Vitals into search rankings: LCP for loading, FID for interactivity, and CLS for visual stability. Even great content gets penalized when a page loads slowly, clicks feel unresponsive, or the layout jumps around while loading.
This calculator converts your three metrics into a 0-100 overall score by comparing them against Google's Good and Poor thresholds. Scores stay near 100 when LCP is under 2.5 seconds, FID is under 100ms, and CLS is under 0.1, and drop linearly as each metric worsens past those limits.
If your score is low, prioritize image optimization, trimming unused JavaScript, and a better font-loading strategy. Real user data is also available in Google Search Console, so use this estimator to set a target and compare it against your actual measurements as you optimize.
Frequently Asked Questions
Each of LCP, FID, and CLS is converted to a 0-100 score based on Google's good and poor thresholds, then averaged into an overall score.
A score of 90 or above is Good, 50-89 is Needs Improvement, and below 50 is Poor. Aim for 90 or higher.
You can check real field data in Google Search Console's Core Web Vitals report, PageSpeed Insights, or the Lighthouse tab in Chrome DevTools.