What Are Core Web Vitals?

When a doctor checks their patient’s vitals, they get a snapshot of that person’s overall health without performing a full examination. Instead, they measure the most important indicators: temperature, heart rate, and blood pressure. This is similar to how Google’s Core Web Vitals give you a sneak peek of your website’s usability health and page experience.

Through three indicating factors, Core Web Vitals allow web developers and site owners to decide where updates need to be applied first.

While your health vitals include heart rate, temperature, and blood pressure, a website’s Core Vitals include:

If you read these terms and felt suddenly overwhelmed, don’t worry. These, like so many other technical SEO and web development terms, are less complicated than they sound. And we’ll explain each in-depth for you.

Google realized that many top-ranking websites didn’t provide an optimal experience for visitors–despite providing relevant content. It was difficult to quantify the usability of a website from a visitor’s perspective with the existing metrics. So, Google made it a mission to fix both.

Was the web experience really that bad? Yes and no. When Google first rolled out their Core Web Vitals, 98% of top-ranking sites did not pass Core Web Vital standards.

It’s important to remember that Google wants to improve the overall health of the web ecosystem. The internet is built for users, after all.

In addition to elevating and setting a standard to measure the biggest complaints among users, it’s important to note that other issues always arise. One is that web development techniques have become extremely diverse. And having metrics for the user experience accounts for all the many ways to architect a website.

Google views these metrics as a way to initiate a sea-change for the entirety of the industry. According to Annie Sullivan with Google’s Core Web Vitals program, by emphasizing the user experience in relation to load time, third-party content management systems like WordPress, Shopify, BigCommerce will be motivated to improve their products. This benefits small businesses, users, and web innovation.

Core Web Vitals are defined by three main metrics: LCP, CLS, and FID. These aspects of a website all impact how long a user interacts with a website.

By focusing on these issues, web developers can greatly improve the user experience. By targeting these metrics, SEO experts can better optimize websites.

LCP is the render time for the biggest content element visible to the user–this differs from First Content Paint (FCP). The LCP does not count any elements that fall below the “fold line.”

So what may be identified as a website’s LCP? Most often your LCP is the page’s featured image or <h1> tag.

However, it could also be:

What Is an Ideal LCP Time?
Ideally, your LCP should be under 2.5 seconds.

Why Does LCP Matter?
The amount of time for the most important elements to load can result in users backing out, increasing your bounce rate and decreasing sales.

CLS quantifies how often visible elements move unexpectedly.

Common causes include:

What Is an Ideal CLS Time?
Your CLS should be under 0.1 seconds.

Why Does CLS Matter?
Unexpected shifts frustrate users, damage experience, and hurt perception of your brand.

FID measures how long it takes for a user to interact with elements such as entry fields or buttons.

Common input interactions include:

What Is an Ideal FID Time?
You want your FID to be under 100 milliseconds.

Why Does FID Matter?
Poor FID can lead to a loss in conversions, as users abandon slow or unresponsive pages.

Core Web Vitals are a ranking metric for Google search results. While there are over 200 factors that determine how your page will rank, poor Web Vitals metrics can have a cumulative negative effect on performance.

Google representatives have confirmed that Web Vitals will continue to influence search rankings in the future.

A user’s first impression matters—online and offline. If your site loads slowly or behaves erratically, users will leave. Improving your Core Web Vitals directly improves engagement and conversions.

The easiest way to audit your website’s core vitals is to perform a free SEO audit to identify issues lowering your score through field data metrics.

Core Web Vital’s Grading Scale: