Website Speed Checker

Website Speed Checker helps your website to make it Faster and Provides all the details and errors of your website

Website Speed Checker Insights reports on the performance of a page on both mobile and desktop devices, and provides suggestions on how that page may be improved.

Website Speed Checker provides both lab and field data about a page. Lab data is useful for debugging performance issues, as it is collected in a controlled environment. However, it may not capture real-world bottlenecks. Field data is useful for capturing true, real-world user experience - but has a more limited set of metrics. See How To Think About Speed Tools for more information on the 2 types of data.

Performance score

At the top of the report, Website Speed Checker provides a score which summarizes the page’s performance. This score is determined by running Lighthouse to collect and analyze lab data about the page. A score of 90 or above is considered good. 50 to 90 is a score that needs improvement, and below 50 is considered poor.

Real-World Field Data

When Website Speed Checker is given a URL, it will look it up in the Chrome User Experience Report (CrUX) dataset. If available, Website Speed Checker reports the First Contentful Paint (FCP), First Input Delay (FID), Largest Contentful Paint (LCP), and Cumulative Layout Shift (CLS) metric data for the origin and potentially the specific page URL.

Classifying Good, Needs Improvement, Poor

Website Speed Checker also classifies field data into 3 buckets, describing experiences deemed good, needs improvement, or poor. Website Speed Checker sets the following thresholds for good / needs improvement / poor, based on our analysis of the CrUX dataset:

Distribution and selected metric values

Website Speed Checker presents a distribution of these metrics so that developers can understand the range of FCP, FID, LCP, and CLS values for that page or origin. This distribution is also split into three categories: Good, Needs Improvement, and Poor, denoted with green, orange, and red bars. For example, seeing 14% within FCP's orange bar indicates that 14% of all observed FCP values fall between 1000ms and 3000ms. This data represents an aggregate view of all page loads over the previous 28-day collection period.

Above the distribution bars, Website Speed Checker reports the 75th percentile for all metrics. The 75th percentile is selected so that developers can understand the most frustrating user experiences on their site. These field metric values are classified as good/needs improvement/poor by applying the same thresholds shown above.

Core Web Vitals

Core Web Vitals are a common set of signals critical to all web experiences. The Core Web Vitals metrics are FID, LCP, and CLS, and they may be aggregated at either the page or origin level. For aggregations with sufficient data in all three metrics, the aggregation passes the Core Web Vitals assessment if the 75th percentiles of all three metrics are Good. Otherwise, the aggregation does not pass the assessment. If the aggregation has insufficient data for FID, then it will pass the assessment if both the 75th percentiles of LCP and CLS are Good. If either LCP or CLS have insufficient data, the page or origin-level aggregation cannot be assessed.