Technical SEO
As of February 2026, Google's Core Web Vitals consist of the same three metrics established after the March 12, 2024 transition. Largest Contentful Paint (LCP) measures loading performance—how quickly the largest visible content element renders. Interaction to Next Paint (INP) measures responsiveness—the latency of all user interactions throughout a page visit. Cumulative Layout Shift (CLS) measures visual stability—how much the page layout unexpectedly shifts.
The three Core Web Vitals—LCP, INP, and CLS—remain unchanged heading into 2026, with no new metrics added since INP replaced FID in March 2024. Google has not tightened any thresholds, but the ecosystem has matured significantly: cross-browser measurement reached all major browsers in December 2025, and global pass rates have climbed to 55.7% of origins. For B2B companies, the average mobile LCP sits at a dismal 7.05 seconds—nearly three times above Google's threshold—representing both a significant problem and an untapped opportunity.
This guide cuts through the noise with current data, practical HubSpot CMS strategies, and evidence-based guidance for B2B companies navigating performance optimisation. Whether you're struggling with mobile speed, trying to prove CWV impact to leadership, or preparing for AI search, you'll find actionable frameworks that connect page performance directly to pipeline.
Contents
The biggest development in 2025 was cross-browser support. Through the Interop 2025 initiative, Firefox 144 (October 2025) added INP support, and Safari 26.2 (December 2025) added both LCP and INP measurement. As of December 12, 2025, LCP and INP are "Baseline Newly Available" across all major browsers. CLS remains Chromium-only, with a proposal for Interop 2026 inclusion.
⚠️ Important distinction
This cross-browser milestone matters for Real User Monitoring (RUM) tools but does not change CrUX data collection, which remains Chrome-only. The CWV ranking signal still reflects Chrome desktop and Android Chrome users.
No new Core Web Vital has been announced. Google's documentation states stable metrics "won't change more than once per year." Two experimental areas are in active research: an animation smoothness metric for quantifying scroll and animation fluidity, and soft navigation measurement for Single Page Applications (a new origin trial launched in Chrome 139, August 2025). Neither is close to production status.
The official Core Web Vitals thresholds have not been tightened since they were originally established. To pass, your site must meet the "Good" threshold for all three metrics at the 75th percentile of page loads from CrUX field data over a 28-day rolling window.
| Metric | Good | Needs Improvement | Poor |
|---|---|---|---|
| LCP | ≤ 2.5 seconds | 2.5s – 4.0s | > 4.0 seconds |
| INP | ≤ 200 ms | 200ms – 500ms | > 500 ms |
| CLS | ≤ 0.1 | 0.1 – 0.25 | > 0.25 |
Global pass rates as of January 2026 CrUX data show 68.3% of origins with good LCP, 87.1% with good INP, and 80.9% with good CLS. Only 55.7% pass all three—up from roughly 50% in early 2024. Desktop pass rates (57.1%) continue to outpace mobile (49.7%), highlighting where most optimisation effort should focus.
Google's threshold documentation does note an aspirational goal of tightening CLS to 0.05 or even 0 once the ecosystem better handles third-party embed shifts, but this remains hypothetical with no announced timeline.
INP represents a fundamental shift in how Google measures interactivity. Where First Input Delay (FID) only captured the delay before the browser started processing the first interaction, INP measures the full latency of every interaction throughout a page visit—from input to the next visual update.
What triggers INP measurement: clicks with a mouse, taps on a touchscreen, and keyboard presses. Hovering, scrolling, and zooming are excluded. Each interaction's latency includes three components:
The practical difference from FID is enormous. Google's own data shows 90% of a user's time on a page is spent after initial load—precisely the window FID missed entirely. A page could score perfectly on FID while delivering a terrible interactive experience because FID only cared about that first click.
Common INP problems to audit
Debugging INP is harder than FID was—it depends on real user behaviour patterns, creating a persistent gap between lab testing and field data. This is one area where Whitehat SEO's website audit service frequently identifies issues that PageSpeed Insights alone cannot surface.
Google's position on CWV and rankings has become clearer through 2025, though deliberately vague on specifics. The key framing: page experience is a ranking signal, not a ranking system—a distinction Danny Sullivan clarified in April 2023 when it was removed from ranking systems documentation but confirmed as an active signal used by other core systems.
John Mueller's most definitive statements bracket the signal's weight precisely: it is "more than a tiebreaker" but "not a giant factor" that "doesn't replace relevance." He has advised that pursuing a perfect CWV score "just for SEO reasons may not be the best use of your time," while noting CWV "affects your site's usability after it ranks."
"Moving from 'poor' to 'good' CWV has measurable ranking impact, particularly in competitive niches where content quality is similar. Moving from 'good' to 'perfect' rarely does."
— Analysis from Whitehat SEO's client performance data
Third-party research provides additional context. Pages ranking at position 1 are 10% more likely to pass CWV than those at position 9, though correlation does not prove causation—sites that invest in SEO tend to invest in performance too. The December 2025 core update saw third-party analysts report that pages with LCP above 3 seconds experienced roughly 23% more traffic loss than faster competitors with similar content.
One critical detail: for sites without sufficient CrUX field data, the CWV signal simply is not used—Mueller confirmed this explicitly for small and local businesses. This affects approximately 88% of pages according to Ahrefs' analysis of 42 million+ URLs.
Google completed its transition to mobile-first indexing in July 2024—every website is now evaluated by mobile Googlebot first. CWV signals are evaluated separately for mobile and desktop: mobile CWV data affects mobile rankings, desktop data affects desktop rankings. The thresholds are identical, but mobile performance is consistently worse due to slower processors, constrained memory, and unreliable network connections.
CrUX data comes exclusively from Chrome desktop and Android Chrome—Safari, Firefox, Edge, and Chrome on iOS (which uses WebKit) do not contribute to ranking signals. This means the CWV ranking signal reflects a subset of real users, skewing toward Android mobile and Chrome desktop.
With 64% of global internet traffic coming from mobile devices, optimising for mobile CWV is the higher-leverage investment. The persistent mobile-desktop gap (49.7% vs. 57.1% pass rates) confirms that mobile remains the harder environment to optimise for—and therefore where competitive advantage is most available.
Industry-specific CWV data reveals B2B sites have significant room for improvement. The average B2B website delivers a mobile LCP of 7.05 seconds—nearly three times Google's 2.5-second threshold. However, B2B sites tend to outperform B2C e-commerce on CLS because their simpler, content-focused layouts produce fewer unexpected shifts.
The conversion impact of speed is pronounced in B2B contexts. Research shows a B2B lead-generation site loading in 1 second converts at 3× the rate of one loading in 5 seconds—a steeper dropoff than B2C e-commerce. A 100-millisecond delay can reduce conversion rates by 7%.
| CMS Platform | CWV Pass Rate (Nov 2025) |
|---|---|
| Duda | 84.87% |
| Wix | 74.86% |
| Squarespace | 70.39% |
| Drupal | 63.27% |
| WordPress | ~46.28% |
HubSpot CMS is notably absent from public benchmark datasets, making direct comparison difficult. Based on Whitehat SEO's experience optimising HubSpot sites, performance varies significantly based on theme choice and implementation approach.
Meanwhile, 13% of top-ranking URLs in B2B niches would receive a CWV ranking boost from passing all three metrics, compared to only 5% in education—suggesting B2B is a vertical where CWV optimisation can genuinely differentiate.
HubSpot CMS ships with solid foundational performance features: a global CDN, automatic image compression with WebP conversion, HTTP/2 support, CSS/JS minification, and CSS combining. The platform's SEO audit tool (available in Content Hub Professional/Enterprise) evaluates all three CWV metrics. These defaults provide a reasonable starting point, but achieving genuinely good CWV scores on HubSpot requires significant additional optimisation, particularly on mobile.
The core challenge is HubSpot's mandatory JavaScript payload. The tracking code, chat widget, forms, and CTA tools each load substantial JavaScript that cannot be fully eliminated. Community reports indicate the chat widget's visitor.js file was historically around 1.39 MB, and mobile Lighthouse scores on typical HubSpot marketplace themes rarely exceed 55.
Practical HubSpot optimisation checklist
async or defer attributes via require_jsOne agency case study showed a 203% mobile performance increase (Lighthouse score from 36 to 73) simply by replacing a marketplace theme with a custom lean theme. HubSpot's Spring Spotlight 2025 introduced a new "Elevate" default theme and CMS React support for building templates, but no 2025-2026 platform updates specifically addressed CWV infrastructure—the fundamental JavaScript payload constraints persist.
For B2B companies on HubSpot where performance is critical, the emerging pattern is to use Webflow or a headless frontend for the website connected to HubSpot for marketing automation via forms and APIs. As a HubSpot Diamond Partner, Whitehat SEO helps clients evaluate whether this architectural approach makes sense for their specific performance requirements and marketing operations complexity.
The 2025-2026 period brought significant changes to performance measurement tools. Lighthouse 13.0 (October 2025) replaced traditional performance audits with streamlined "Insights"—prioritised, actionable recommendations with estimated impact scores. Multiple legacy audits were removed entirely, including offscreen-images, uses-rel-preload, and first-meaningful-paint.
The standalone Lighthouse panel in Chrome DevTools was sunset in H2 2025, with its functionality absorbed into a comprehensively overhauled Performance panel. This panel now features a live metrics screen showing real-time local CWV alongside CrUX field data, an insights sidebar powered by Lighthouse analysis, and AI/Gemini integration (Chrome 137+) that lets developers chat with an AI about specific performance issues.
The CrUX Dashboard was deprecated in November 2025, replaced by CrUX Vis (cruxvis.withgoogle.com)—a faster tool offering weekly updates, both origin and URL-level data, and additional metrics. PageSpeed Insights now displays the CrUX data collection period dates for transparency. The web-vitals Chrome extension was archived in February 2025, with its features integrated into DevTools.
Google's official AI features documentation makes no mention of Core Web Vitals or page speed as selection criteria for AI Overviews or AI Mode. The documentation states plainly: "There are no additional requirements to appear in AI Overviews or AI Mode... nor other special optimisations necessary."
The connection is indirect but meaningful. Third-party analysis shows 97% of sources cited in AI Overviews come from the top 20 organic results for a query. Since CWV contributes to organic rankings, better CWV performance feeds a pipeline: improved CWV → better rankings → higher likelihood of AI Overview citation.
However, court documents from Google's 2025 antitrust case revealed that FastSearch, the system powering AI Overviews, uses RankEmbed (semantic matching) rather than the full traditional ranking pipeline, prioritising speed and semantic relevance. This suggests CWV may have less direct influence in AI Overview selection than in traditional search.
For B2B companies investing in Answer Engine Optimisation (AEO), CWV should be treated as table-stakes hygiene—necessary for maintaining strong organic positions that feed AI citation eligibility—rather than a direct lever for AI visibility. Content quality, E-E-A-T signals, structured data, and topical authority remain the primary drivers of AI Overview inclusion.
Recent case studies demonstrate that CWV improvements deliver measurable business outcomes, with the strongest results tied to LCP and INP optimisation:
Vodafone Italy improved LCP by 31%, generating 8% more sales and 15% better lead-to-visit rates through server-side rendering and hero image optimisation.
redBus reduced INP by 72% (from 870ms to ~250ms) by debouncing scroll handlers and reducing fetch batch sizes, producing a 7% increase in sales.
Renault found that every 1-second LCP improvement drove 14% lower bounce rates and 13% higher conversions.
Preply improved INP from ~250ms to 185ms on their Next.js application, estimating ~$200K/year in SEO value from entering the "good" INP zone.
Link-Assistant.com observed a 30% decrease in organic clicks within one week when URLs degraded from "green" to "amber" CWV status—with full recovery upon returning to "green."
The pattern across these studies is consistent: the largest business gains come from moving out of "poor" into "good" territory, particularly on LCP and INP. The conversion impact is especially steep for lead-generation and B2B sites, where the speed-to-conversion relationship is roughly 3× more pronounced than for B2C e-commerce.
The thresholds remain unchanged: LCP should be 2.5 seconds or less, INP should be 200 milliseconds or less, and CLS should be 0.1 or less. These are measured at the 75th percentile of page loads. All three metrics must pass for a page to earn a "good" CWV assessment.
CWV is a confirmed ranking signal that Google describes as "more than a tiebreaker" but "not a giant factor." In competitive niches where content quality is similar, passing CWV provides measurable advantage. Pages with LCP above 3 seconds experienced 23% more traffic loss in the December 2025 core update than faster competitors.
Yes, but it requires deliberate optimisation beyond default settings. HubSpot's mandatory JavaScript payload for tracking, chat, and forms creates baseline performance constraints. Start with the CMS Boilerplate theme, restrict chat widget loading, preload LCP images, and keep combined CSS/JS under 200 KB on key pages.
Not directly. Google's AI features documentation makes no mention of CWV as selection criteria. However, 97% of AI Overview citations come from top 20 organic results—so better CWV contributes indirectly by improving your organic rankings that feed AI citation eligibility.
LCP (Largest Contentful Paint) typically delivers the highest ROI for B2B sites. With average B2B mobile LCP at 7.05 seconds—nearly 3× the threshold—there's significant room for improvement. Case studies consistently show LCP optimisation driving the largest conversion and revenue gains.
Core Web Vitals in 2026 represent a mature, stable initiative—the metrics and thresholds are settled, the tooling has been significantly upgraded, and cross-browser measurement is finally a reality. For B2B companies, the strategic calculus is clear: CWV is not a ranking silver bullet, but failing to meet thresholds creates measurable drag on both search visibility and conversion rates.
The average B2B site's 7.05-second mobile LCP represents a significant competitive gap. Companies on HubSpot CMS face platform-specific constraints that require custom theme development and strategic script management. The most important new development to monitor is soft navigation measurement for SPAs, which could fundamentally change how CWV applies to JavaScript-heavy B2B applications.
The connection between CWV and AI Overviews remains indirect—invest in CWV for its proven conversion and ranking benefits, not as an AI optimisation strategy. Content quality, structured data, and topical authority remain the primary drivers of AI citation. CWV simply ensures you're not disqualified from consideration.
Whitehat SEO's technical audits identify the CWV issues PageSpeed Insights alone can't surface—and connect performance improvements directly to pipeline impact in your HubSpot reporting.
Get Your Free CWV Audit →About Whitehat SEO
Whitehat SEO is a London-based HubSpot Diamond Solutions Partner and full-service inbound marketing agency. Since 2011, we've helped B2B companies turn their marketing investment into predictable pipeline through integrated SEO, AEO, and HubSpot optimisation. We run the world's largest HubSpot User Group (London HUG).
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