loader image
get in touch
  • Google’s Core Web Vitals: All You Need to Know

Google’s Core Web Vitals: All You Need to Know

May 24, 2021

Last November, Google announced that the Page Experience Update would roll out in May 2021. As of now, the search giant has delayed the launch till June 2021. However, SEO experts around the world are anticipating what the algorithm changes will hold in store. 

So far, we know that the Page Experience Update will impact ranking signals. Not only will it be prioritising existing signals, but it will also incorporate new ones that are deemed necessary by the search engine. 

These ranking signals will include the Core Web Vitals, 

What are Core Web Vitals?

Core Web Vitals is a set of metrics defined by Google to measure the page speed, performance in responsiveness and visual stability of websites. Namely, Largest Contentful Paint (LCP), First Input Delay (FID) and Cumulative Layout Shift (CLS) are the three web vitals declared as prioritised ranking signals.

One way or another, we can conclude that these three factors ultimately determine the speed of the site. Whether it’s the loading time, the interactivity of the website and responsiveness with regards to various actions performed, we can safely say that maintaining the site’s speed is integral.

What’s interesting is that unlike other updates and guidelines published by the search giant, these are the most clearly defined metrics we’ve gotten yet. What this means is that we now have a clear picture regarding what will affect our site’s rankings. Compared to vague and generalised guidelines, these provide specific details about how a site can perform well enough. However, it should be noted that Google has also declared that useful, unique and quality content will inevitably be preferred. So, apart from other core web vitals, content matters as well.

Since it’s a crucial update that is going to impact SERPs, let’s take a look at the Core Web Vitals in detail:

Largest Contentful Paint

This is the metric that measures the loading performance of the site. More specifically, it looks at the loading time of the largest element of the website. It could be an image, a video or even a substantially large block of textual content that is bigger than the other elements present on-page. The largest content should appear in front of the user as soon as possible. This gives users the satisfaction that their page is being loaded instead of making them wonder if it’ll ever open.

As per the search engine’s guidelines, your LCP should be less than 2.5 seconds to be considered good. At the same time, it can go up to 4 seconds before it is considered poor and penalised as such.

First Input Delay

First Input Delay refers to the time taken by the website to respond to any interaction made on it. For example, if a visitor on your site clicks on any link, button, etc., the time taken by the website to start working on displaying the required information is referred to as FID. 

As we can judge, this metric also targets the speed element of the website, though it takes a rather subtle, direct and specific approach. You will also hear the term TBT or Total Blocking Time being used in place of FID. While both of these point to the same thing, they are different because the former uses lab data rather than field data that is required by the latter. Since we don’t always have field data for the website’s we are working upon, we resort to TBT instead of FID.

Webmasters are encouraged to bring their website’s FID to as low as 100 milliseconds if they want to get positive ratings. Being around 300ms is also okay as this is the bracket that Google deems, ‘Needs Improvement”. Taking any more than 300ms will inevitably result in the website getting penalised.  

Cumulative Layout Shift

CLS focuses on the stability of the webpage with regards to visualisation. We’ve noted several times how websites with images, video and text blocks often glitch out or have difficulties in executing smooth transitions when we scroll. This is something Google terms as a layout shift.

Since it’s clearly an obtrusion for a visitor to have a website that doesn’t remain stable when navigating, Google can’t help but penalise websites that don’t fix this. That is why the search giant has deemed a value of 0.1 or less as the ideal CLS for a website. Going above 0.1 but staying below 0.25 will land you in the “Needs Improvement” bracket. Score higher than this, and you can expect your rankings to fall down quicker than you can say, “Oh No!”

How to Audit and Improve Core Web Vitals?

Now that we know what LCP, FID and CLS are, let’s take a look at how we can measure them before Google does and improve our scores.

Firstly, you need to make sure that you have a paid version of a website crawler like Screaming Frog, PageSpeed Insights API key, and the domain of the website you’re auditing.

Once you connect your PageSpeed Insights API key to your Screaming Frog crawler, you’ll have options to collect different metrics. To name some options that will be available, you can choose from CrUX, Lighthouse Metrics, Opportunities and Diagnostics. Although you can tick all of these boxes, make sure that you don’t run out of your query limit. If you’re close to running out, we suggest taking in Lighthouse metrics as they consist of LCP, TBT and CLS.

Now that you’ve selected the metrics you need to gather, run the crawler and wait for it to finish collecting data. After the API and Crawl loading bars reach 100%, you can export your data with regards to specific fields. This helps SEOs organise data according to various issues, site sections, individual pages, etc.

For example, you can sort the data by applying a filter that allows you to narrow down pages that specifically have PageSpeed issues. You can further navigate through this data and filter columns to find:

  • LCP of 4 seconds or more
  • FID or TBT of 300ms or more
  • CLS scores of 0.25 or more

This will ultimately give you a full list of the pages that are struggling with these issues. Thereby, developers can easily navigate to the problem and focus on solving them. Not only will this help you segment the issues and find generalisations (such as whether the issues are mostly in the blog section, etc.), but it will also reduce the time taken to fix them as well.


After developing an understanding of what the Core Web Vitals are, you can start working upon your website’s performance for the upcoming Page Experience Update that rolls out in June 2021. Instead of watching your keywords dance in rankings and hoping they don’t end up in later pages, it’s advised that you focus on preparing beforehand. 

For businesses and companies that are facing troubles or want guaranteed results, we recommend getting in touch with experts at Zoom Digital. Promising top-tier digital marketing services along with excellent and commendable customer support, you can be sure that your business will be on its way to the top. 

Related Blog

September 20, 2021

Mobile apps for SME’s – what are your chances to scale your local business

Nearly 70% of worldwide brands are now depending on mobile apps for their businesses of all sizes.
Read More

September 16, 2021

What is App Store Optimization and Why is it Important?

App store optimization, also known as ASO, is a systematic process of optimizing mobile apps to be more visible to potential customers.
Read More

September 13, 2021

Creative Ideas and Best Practices for A Lead Generation Campaign

The lead generation process comprises efforts of targeting and identifying emerging potential customers
Read More

September 9, 2021

All About Off-Page Optimization and Its Importance to Establish a Credible Online Presence

Off-Page SEO is a popular term that defines a set of actions that experts do off a website to develop links that redirect users to the said webpage.
Read More

August 30, 2021

7 Simple Steps to Draft a Kick-ass Social Media Strategy

Social media is the perfect platform to kick start because not just that it is a power-packed tool but it’s FREE!
Read More

August 23, 2021

All that you need to know about the iOS 14 update and its impact on digital adverting.

Every iOS update affects usability, marketing and adverting. Find out about what impact iOS 14 has on digital advertising in this article.
Read More

August 19, 2021

Bounce Rate and SEO, How does it affect your search ranking?

What is Bounce Rate? The bounce rate is defined as the total percentage of people who come to visit your website's home page and leave or “bounce off” without stay or browsing any other website pages.
Read More

August 16, 2021

4 Handy Tips to Market Yourself on Social Media

Do you know that of all adults, about 75% use social media? Interesting right!
Read More

August 5, 2021

How To Select The Best Digital Marketing Agency For Your Business?

“Do you know that 70% of digital marketers are desperately financing in content marketing whereas 93% of all online interactions are triggered with search engines?”
Read More

got a project in mind?

get in touch