What is Lighthouse 8.0?

Google Lighthouse 8.0 is the recently updated version of the Lighthouse Performance Assessment. The Lighthouse Performance Score measures the performance of the website based on certain parameters or individual scores.

The Lighthouse tool is a Chrome developer tool that supports all speed metrics and other parameters of an online site. Therefore, the focus is on accessibility and SEO development.

The weighting of each lighthouse update score is different. The more or less your website’s Lighthouse Performance Score varies, the more your website is likely to be affected by the update, both positively and negatively. You will read that later in the article.

So what are the parameters that Google Lighthouse 8.0 takes into account?

What are the focused parameters for Lighthouse 8.0?

The Lighthouse 8.0 contains six key parameters as described below.

FCP (First Contentful Paint)

First Contentful Page is a performance metric for the Lighthouse that measures how long it takes for your website to display the DOM content.

What is DOM content?

DOM content can be the SVG elements on your page, the images, and so on.

The Document Object Model, or DOM for short, acts as a page interface and can change the page structure and content.

Speed ​​index

The speed index is measured in seconds. It is the time when your website is loaded and visually displayed.

LCP (Largest Contentful Paint)

The Largest Contentful Paint (LCP) is one of the core parameters of the lighthouse update. It measures how quickly the most content on your page loads. The big content is related to the title, carousel, featured image, video, etc.

The longer it takes for the larger content to load on the page, the more it affects the page load time and thus the user experience.

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TTI (time to interactivity)

Time to Interactive is a key Lighthouse 8.0 parameter that measures the interactivity (or responsiveness) of your website.

In other words, TTI measures the unusable surface of your website that otherwise looks interactive.

For example, you might have experienced while visiting a website that looks perfectly fine but doesn’t support interactive elements like a login button or a broken link.

TBT (total blocking time)

The total blocking time measures the longest time that your website has been blocked for your users.

You may be wondering if TBT and TTI are the same?

TBT and TTI measure completely different aspects of a page, but they come together to provide a detailed analysis of your website’s responsiveness.

The TBT metric tells you which Javascript file is taking the longest to load, thus preventing users from entering input on your page.

CLS (cumulative layout shift)

Cumulative Layout Shift (CLS) is the most important metric that Lighthouse 8.0 considers. CLS measures the stability of the visual elements on your website.

In other words, CLS measures how much your website elements move from their dedicated position on the page.

The webmaster’s goal should be to keep the CLS score low, which in turn suggests that a page is easy to use and stable enough to run.

What are the changes in the Lighthouse 8.0 scores?

Google’s Lighthouse 8.0 update made the scoring parameters more stringent to measure, while relaxing some metrics. Below is a summary of the changes:

  • The First Contentful Paint (FCP) metric is measured more strictly than before.
  • The cumulative layout shift (CLS) metric scoring is less stringent.
  • The Total Blocking Time (TBT) metric has proven to be stricter.

According to Google estimates, almost 20% of websites will see a decrease of up to five points. Almost another 20% of sites are likely to remain unaffected, and the remaining 60% of sites are expected to have a positive impact and improve rankings by up to five points or more.

Here’s what Google thinks about the impact of the Lighthouse 8.0 update.

– ~ 20% of websites can see a drop of up to 5 points, although probably less

– ~ 20% of the websites will hardly notice any noticeable changes

– ~ 30% of websites should see moderate improvement on some points

– ~ 30% could see a significant improvement of 5 points or more

The sharp decline in the performance rating is due to the tightening of the TBT measure. Therefore, the overall performance rating of Lighthouse 8.0 is reduced more for websites that are severely affected due to the TBT factor.

Lighthouse 8.0: Before and after implementation

Below is the comparison of Lighthouse 6 and Lighthouse 8 based on weight shift. If you notice carefully, the top three metrics that have seen a major shift in weight are the CLS, TBT, and LCP metrics.

The weight of the CLS metric has been increased from 5% to 15%. The weighting of the TBT metric has also increased from 25% to 30%.

On the other hand, the weighting of the remaining three metrics TTI, SI and FCP is reduced from 15% to 10%.

Performance metrics Weight in lighthouse 6 Weight in lighthouse 8
Cumulative Layout Shift (CLS) 5 fifteen
Total Lockout Time (TBT) 25th 30th
Largest Contentful Paint (LCP) 25th 25th
Time to Interactivity (TTI) fifteen 10
Speed ​​index (SI) fifteen 10
First Contentful Paint (FCP) fifteen 10

What can you do to improve the performance evaluation?

Use the calculator to measure the Lighthouse 8.0 performance metrics. You can use this calculator to see how the overall performance score changes as each metric changes.

The ideal values ​​of the metrics should be retained. Below are the standard Google guidelines for considering the impact of individual metrics.

Once you know the value of each of the metrics, you can use the reference above to determine the right implementation and improve the overall performance score.