Core Web Vitals (CWV) are a set of metrics that Google uses to measure the real-world user experience of a web page. Instead of just checking if the code is valid, these metrics capture three key aspects of how a page performs: how quickly the main content loads, how stable the page layout is during loading, and how responsive the page is to user interactions.
For business and technology leaders, Core Web Vitals provide a clear way to understand how technical investments impact crucial business outcomes. Improving these metrics can directly enhance a site’s search engine ranking, increase user trust, and ultimately lead to improved conversion rates.
The three metrics every leader needs to understand
These metrics, known as Core Web Vitals, give leaders a crucial understanding of their website’s performance. It also measures real-world user experience and is crucial for improving site performance and user satisfaction.
- Largest Contentful Paint (LCP): This metric measures perceived load speed. It pinpoints when a page’s main content, like a hero image or a block of text, fully loads and becomes visible to a user. To deliver a great user experience, your LCP should be 2.5 seconds or less.
- Interaction to Next Paint (INP): Replacing the older First Input Delay metric in 2024, INP is a measure of a page’s overall responsiveness and interactivity. It tracks how quickly a page responds after a user interaction, like clicking a button. For a smooth user experience, aim for an INP of 200 milliseconds or less.
- Cumulative Layout Shift (CLS): CLS measures a page’s visual stability. It quantifies how much a page’s layout unexpectedly shifts as it loads, which can cause frustrating experiences like a user accidentally clicking the wrong button. A good CLS score is 0.1 or less.
Because these are field metrics, they reflect the real-world experiences of your actual users. Focusing on improving these three metrics directly improves the experience of real customers, not just a lab-based test. Leaders who understand and prioritise these metrics can make data-driven decisions that lead to better site performance and happier users.
Why does Core Web Vitals matter?
Core Web Vitals are a big deal for businesses because they directly impact your bottom line. They affect two key business realities: discoverability (how easily people find you) and conversion efficiency (how many of those visitors become customers). Improving your Core Web Vitals is often a faster and more effective way to boost revenue than many traditional marketing campaigns.
Google uses Core Web Vitals as a significant part of its broader Page Experience signals. While these metrics aren’t the only factor determining your search engine ranking, they are a powerful, measurable input that influences your visibility. This is especially true for competitive queries where even minor differences in page performance can make or break a website’s position on the search results page.
A website with strong Core Web Vitals scores has a better chance of ranking higher, which in turn drives more organic traffic and potential customers to your site.
Beyond discoverability, Core Web Vitals directly affect your conversion rates. User behaviour data from Google shows that visitors are incredibly impatient, especially on mobile devices. Roughly 53% of mobile visits are abandoned if a page takes longer than three seconds to load. Even a one-second delay can cause a significant drop in conversions.
When you improve your page’s load times and responsiveness, you’re not just making your site faster; you’re creating a better user experience that encourages visitors to stay, engage, and ultimately, convert into paying customers. This is why optimising your Core Web Vitals is a powerful strategy to boost revenue.
How to measure CWV the right way
To effectively measure Core Web Vitals, you need to combine both field data (real user data) and lab data (simulated data). Here’s a comprehensive guide on how to approach it:
Start with Google Search Console
The Core Web Vitals report in Google Search Console is your first and most important stop. This report provides a high-level overview of how real users experience your site. It groups your URLs into three categories based on field data:
- Good: URLs that meet the CWV thresholds.
- Needs Improvement: URLs that fall short of the CWV thresholds.
- Poor: URLs that fail to meet the CWV thresholds.
Use this report to identify which pages are performing poorly for your users and prioritise your optimisation efforts.
Combine Field and Lab Data
For detailed diagnostics, use tools that provide both field and lab data. This combination gives you a complete picture of performance.
- Field Data: This is the data you get from the Chrome User Experience Report (CrUX), which measures how real users experience your site in the wild. This data is the source for the Search Console and PageSpeed Insights field data reports. CrUX data is the “source of truth” for your CWV performance.
- Lab Data: This data is captured in a controlled environment using tools like Lighthouse or PageSpeed Insights. It simulates how a user would experience your page. Lab data is excellent for diagnostics because it provides reproducible results and pinpoints specific issues, such as slow server response times or unoptimized images, that you can fix to improve performance.
Use Diagnostic Tools
Once you identify pages that need improvement, use the following tools for a deeper dive:
- PageSpeed Insights (PSI): PSI is an essential tool that provides both CrUX field data and Lighthouse lab data for a specific URL. Use it to diagnose specific issues on a page. The lab data section will give you actionable recommendations to fix performance bottlenecks.
- Lighthouse: Integrated into Chrome DevTools, Lighthouse runs a series of audits against a page and generates a report with performance scores and suggestions. It’s perfect for testing changes locally before deploying them to your live site.
- Chrome User Experience Report (CrUX): For programmatic monitoring of a large number of pages, you can use the CrUX API. This allows you to programmatically pull field data for many URLs or even entire origins, giving you a scalable way to track your site’s performance over time.
Programmatic Monitoring
To continuously monitor your site’s CWV performance, you can use the PageSpeed Insights API or the CrUX data. This approach allows you to automate the process of collecting data, providing a scalable way to track your site’s performance over time. You can integrate this data into your performance dashboards to monitor your key pages and ensure that any new deployments don’t introduce performance regressions.
Strategic Governance & KPIs
To treat CWV like a product metric, start by setting a clear, measurable goal. For example, aim for 75% of your key landing pages to achieve a “Good” rating for all three Core Web Vitals. This goal directly ties engineering effort to a tangible outcome.
Next, connect this goal to a critical business KPI, such as organic revenue or conversion rate for organic visitors. This link translates the technical work into financial terms that executives can easily understand. Fund a dedicated, time-boxed engineering sprint to deliver these improvements, ensuring the project has the necessary resources and focus.
Measurement & Verification
Effective implementation requires a two-pronged approach to data. First, use field data monitoring to track real-world user performance on your site. This provides a baseline and shows the impact of your changes over time.
Second, use A/B experiments to verify that the CWV improvements actually lead to a conversion lift. By testing the optimised pages against the original versions, you can prove the positive business impact before you scale the changes across your entire site. This data-driven approach ensures a strong return on investment.
Finally, Leaders must act now. Core Web Vitals provide a clear, compelling language for executives. They translate complex engineering work into seconds, scores, and revenue. The fixes are often technically straightforward but yield significant, compounding returns because organic traffic is a recurring and valuable asset.
For any business focused on discoverability and conversion, CWV is a powerful strategic lever for growth. Start by conducting a thorough audit of your site this quarter, prioritizing high-demand pages that drive the most traffic and revenue. Then, measure the direct impact on revenue. The return on investment (ROI) from these efforts can be both rapid and durable, making it an essential part of your digital strategy.