August 12, 2019
Google Lighthouse score

What is the ‘Google score’ in your portfolio exactly, you ask? The short answer is: it is a measurement from Google, that indicates the quality of a website.

To generate this score Google renders the website in Chrome. While doing so, Google analyzes the code and performance of your website in a series of audits. These audits are seperated into four categories: Performance, Accessibility, Best Practices and SEO. Each category scores between 0 and 100, where 100 is the best and 0 is the worst score. If you want to check the score or the audits yourself, you can do so at the web.dev website.

Note that on this website I use the average of these four categories as the ‘Google score’ for simplicity reasons.

Performance

Performance is the speed at which a website loads. Lighthouse returns a Performance score between 0 and 100. 0 is the lowest possible score. 100 is the best possible score which represents the 98th percentile, a top-performing site. A score of 50 represents the 75th percentile. An important performance metric is the Speed index.

Accessibility

Accessibility is the design of products, devices, services, or environments for people with disabilities. The Accessibility score is a weighted average of all the accessibility audits. See Scoring Details for a full list of how each audit is weighted. The heavier-weighted audits have a bigger impact on your score.

Best Practices

Best Practices is a list of audits that check common mistakes in web development. Lighthouse returns a Best Practices score between 0 and 100. 0 is the worst possible score, and 100 is the best. The Best Practices audits are equally weighted.

SEO

Search engine optimization (SEO) is the process of increasing the quality and quantity of website traffic by increasing the visibility of a website or a web page to users of a web search engine. Lighthouse returns a SEO score between 0 and 100. 0 is the worst possible score, and 100 is the best. A website with a high SEO score will end up higher in the search results than a website with a low SEO score.

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