Since 2021, Google has been evaluating all websites based on three user experience metrics, collectively known as Core Web Vitals. These metrics directly influence search engine rankings and help determine whether your law firm's website appears before or after its competitors in search results.
The unique aspect: Google doesn't measure how quickly your page loads in a lab test, but rather how real visitors actually experience your site. The measurement is based on the 75th percentile – meaning that 75% of your visitors must have a "good" experience for your page to be rated as good. This is particularly relevant for law firms that rely on mobile search queries and local visibility: Google primarily evaluates Core Web Vitals based on the mobile version of your website.
This article explains what the three metrics mean, how to measure your values, and which specific actions will have the greatest impact. For the overall strategy, see our page. Web design for lawyers as well as our contribution Mobile-first for law firms.
An overview of the three Core Web Vitals
All three metrics have defined thresholds that Google classifies as "good", "needs improvement" or "bad":
| Metric | What is being measured | Good | Need for improvement | Bad |
| LCP | Loading speed: When does the largest visible element appear? | < 2.5 s | 2.5 – 4.0 s | > 4.0 s |
| INP | Interactivity: How quickly does the page respond to input? | < 200 ms | 200 – 500 ms | > 500 ms |
| CLS | Visual stability: How much do elements shift during loading? | < 0.1 | 0.1 – 0.25 | > 0.25 |
| Important: INP has replaced FIDSince March 2024, Interaction to Next Paint (INP) has replaced the old metric First Input Delay (FID). INP measures not only the first interaction, but all clicks and inputs throughout the entire page visit – a significantly stricter standard. |
LCP – Largest Contentful Paint – measures how long it takes for the largest visible element of a page to fully load. This could be a header image, a block of text, or a video. Google considers LCP an indicator of perceived loading speed because it captures the moment when the visitor feels the page is ready.
INP – Interaction to Next Paint – replaced the older First Input Delay (FID) in March 2024. While FID only measured the first interaction, INP evaluates every interaction throughout the entire page visit: every click, every input, every tap. This makes INP a significantly more rigorous measure of a page's responsiveness.
CLS – Cumulative Layout Shift – measures whether page elements unexpectedly shift their position during loading. A typical example: A user wants to click on "Contact," but an image loads and moves the button – the click lands in the wrong place. CLS evaluates precisely this problem and is particularly relevant on mobile devices.
What does "75th percentile" mean in Core Web Vitals?
Google does not evaluate the average, but rather the worst 25 page visits (%). The 75th percentile means that 75% of your visitors should have a "good" experience. The 25 slowest visitors should not consistently produce poor results. This is important because a fast desktop browser cannot compensate for the poor performance of a slow mobile device. Google Search Console displays these field values based on actual visitors.
Does the ranking apply to mobile or desktop devices?
Google primarily evaluates the mobile version – Mobile-First Indexing has been fully active since 2023. PageSpeed Insights displays scores for both desktop and mobile versions, but the mobile score is crucial for ranking. A page with an excellent desktop score but a poor mobile score will be ranked lower by Google. Law firms looking to improve their Core Web Vitals should therefore always prioritize their mobile score.
Is a good PageSpeed Insights result enough for good rankings?
PageSpeed score and Core Web Vitals are related, but not identical. The PageSpeed score (0–100) is based on lab data and simulated conditions. Core Web Vitals in Google Search Console are based on real-world field data from CrUX. Field data is what determines ranking. A page can have a PageSpeed score of 90 and still have poor Core Web Vitals field scores if real users are accessing the page on slow devices or poor networks.
How do you measure your Core Web Vitals?
For law firms that want to check their own website, there are three recommended free tools:
- Google PageSpeed Insights: pagespeed.web.dev – displays lab data and real field data (CrUX) for each URL; provides specific recommendations for action.
- Google Search Console: Under Experience → Core Web Vitals you will find an overview of all URL groups with their status – sorted by mobile and desktop.
- GTmetrix: gtmetrix.com – Detailed waterfall view; shows which resources are blocking loading times
Important: Always measure the mobile version. Google indexes your site according to the mobile-first principle – the mobile value is the decisive factor.
The most common problems and their solutions
The following table shows the seven most common Core Web Vitals problems on law firm websites – with specific countermeasures:
| problem | impact | Solution |
| Large images without WebP format | Poor LCP | Convert images to WebP and scale them to screen size; Plugin: Imagify or ShortPixel |
| No caching active | Poor LCP, high TTFB | Set up a caching plugin: WP Rocket or FlyingPress; aim for a server response time of under 200 ms. |
| Google Fonts loaded externally | LCP and CLS | Embed fonts locally; OMGF plugin; also relevant to GDPR (see GDPR article) |
| No lazy loading | Poor LCP | Images below the visible area load only when scrolling; available by default in WordPress 5.5+. |
| Heavy JavaScript libraries | Poor INP | Disable unnecessary plugins; load scripts asynchronously or by default; use query monitor for analysis. |
| Images without height/width attribute | Poor CLS | Assign width and height to each image in the HTML; this prevents the browser from reserving space and then jumping to the correct image. |
| Advertising banner or consent popup without a fixed size | Poor CLS | Fix popup size; prevent content from shifting after page load; reserve space for consent banners. |
Improve the Core Web Vitals of your law firm website
OMmatic analyzes your current PageSpeed scores and implements the optimization measures that will have the greatest impact on your rankings.
Frequently Asked Questions
How much do Core Web Vitals affect ranking?
Core Web Vitals are a ranking factor, but not a dominant one. Google has confirmed that Core Web Vitals are part of the ranking signals. All other factors being equal, the technically superior site wins. For law firms with strong content and good EEAT (Emergency Applicable Knowledge), CWV are an additional lever, not a replacement. However, law firms with poor scores risk being at a disadvantage compared to their competitors.
Can I improve Core Web Vitals without a developer?
Some measures can be implemented without coding, while others require technical support. Installing a caching plugin (WP Rocket, FlyingPress) and an image optimization plugin (Imagify) is easy to do without a developer. Fixing CLS issues (images without dimensions) or INP problems (heavy JavaScript libraries) usually requires technical expertise.
How often should I check my Core Web Vitals?
After every major update and at least once a quarter, Google Search Console automatically displays CWV issues. After installing new plugins, theme updates, or content changes, a manual check with PageSpeed Insights is recommended, as every change can introduce new problems.
What is the fastest single lever for LCP improvement?
A correctly configured caching plugin. Caching drastically reduces the time to first byte (TTFB), which directly results in a better LCP. WP Rocket with server caching and lazy loading enabled can improve LCP values from "poor" to "good" in many cases.
What does the 75th percentile mean in Core Web Vitals?
Google doesn't evaluate the average, but rather the worst 25 percentiles (%) of page visits. The 75th percentile means that 75 percent of your visitors must have a good experience. The slowest 25 percentiles (%) must not consistently produce poor results. This is important because a fast desktop browser cannot compensate for the poor performance of a slow mobile device. Google Search Console displays these field values based on actual visitors.
Does the ranking apply to mobile or desktop devices?
Google primarily evaluates the mobile version – Mobile-First Indexing has been fully active since 2023. PageSpeed Insights shows scores for both versions, but the mobile score is crucial for ranking. A page with an excellent desktop score but a poor mobile score will be ranked lower by Google. Law firms should therefore always optimize their mobile performance first.
Is a good PageSpeed score enough for good rankings?
PageSpeed score and Core Web Vitals are related, but not identical. The PageSpeed score (0–100) is based on lab data and simulated conditions. Core Web Vitals in Google Search Console are based on real field data from CrUX. Field data is what determines ranking. A page can have a PageSpeed score of 90 and still have poor Core Web Vitals field values.
Conclusion
Core Web Vitals are not abstract technical metrics, but rather measure how clients actually experience your website: How fast does it load? Is it responsive to touch? Does the content jump around during loading? Optimizing these three dimensions not only improves Google rankings, but also the conversion rate. Our section describes the technical integration into an overall strategy. Web design for lawyers.
Optimize the technical performance of your law firm's website
OMmatic improves the LCP, INP and CLS of your WordPress website – from image optimization to caching.