Home Learning CentreGoogle’s Core Web Vitals: How They Impact SEO & What You Need to Fix Now

Google’s Core Web Vitals: How They Impact SEO & What You Need to Fix Now

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David Neale   -   25/08/2025
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You want pages that load fast, feel responsive and stay stable. Core Web Vitals (CWV) measure that experience. They sit at the centre of website optimisation. On 12 March 2024, INP replaced FID as a Core Web Vital (FID deprecated). Older checklists need a refresh.

Start simple. Baseline in Search Console. Fix LCP/INP/CLS on three priority templates. Then verify in PageSpeed Insights. Treat 10 days as an example window. It’s short enough to ship and flexible for access, QA and approvals. Field data (CrUX) updates gradually as users return. If foundational issues block progress, consider targeted website design to remove bottlenecks early.

Prefer a quick diagnosis? Request a Free Website Audit and get a ranked backlog with a quick‑win sprint to start fast!

What Are Core Web Vitals and Why Do They Matter for Website Optimisation?

Core Web Vitals are three user‑experience metrics: LCP (Largest Contentful Paint), INP (Interaction to Next Paint), and CLS (Cumulative Layout Shift). Aim for LCP ≤ 2.5s, INP ≤ 200ms and CLS ≤ 0.1 at the 75th percentile. Good CWV support page experience. They align with what ranking systems reward, alongside relevance and helpful content.

How Do I Check My Site’s Core Web Vitals Today?

Go to Search Console → Core Web Vitals to see real‑user (CrUX) data for mobile and desktop. Next, test a URL in PageSpeed Insights to see field (CrUX) data and lab (Lighthouse) diagnostics in one place. Use field data for truth and lab data to debug. In Search Console, Core Web Vitals has separate reports for mobile and desktop. Together they give you a reliable baseline for website optimisation decisions.

Which Core Web Vitals Should I Fix First for the Biggest Impact?

Start with LCP on revenue pages. Next, reduce INP issues that block responsiveness and keep CLS green to protect usability. This order often lifts satisfaction and conversions. It mirrors common guidance. In practice, fix revenue pages first. For most stacks, this is a practical website optimisation sequence.

Website Optimisation Fixes That Move LCP, INP and CLS Fast

LCP (loading)

  • Prioritise the LCP resource in HTML (preload it) and serve a smaller, responsive image (WebP/AVIF).
  • Reduce TTFB via CDN/caching and defer non‑critical resources.

INP (responsiveness)

  • Break up long tasks, defer non‑critical JavaScript, and remove dead scripts.
  • Avoid heavy main‑thread work during interactions; profile with DevTools.

CLS (visual stability)

  • Set width/height (or aspect‑ratio) on images and embeds (including the LCP image).
  • Reserve space for ads and late‑loading UI; avoid layout‑shifting animations; prefer transform/opacity for animations.

If your templates block progress, scope a focused website design pass instead of chasing micro‑gains.

Do Core Web Vitals Affect SEO Directly?

Core Web Vitals are used by Google’s ranking systems alongside many other signals. Achieving “good” results helps, but they don’t replace relevance or other ranking signals.

A 10‑Day Website Optimisation Quick‑Strike (Example Timeline)

Goal: ship a first wave of changes in about 10 days on 2–3 high‑value templates, with low risk.

Timeframes vary by stack, access and approvals. Use this as a planning guide; field (CrUX) trends update gradually as real users return.

Days 1–2 — Baseline in Search Console (mobile/desktop), pick three priority templates, export PageSpeed Insights reports and start a simple change log.

Days 3–4 — Lift LCP: compress and convert hero media (WebP/AVIF), preload the LCP resource, and trim render‑blocking CSS/JS; retest in PSI.

Days 5–6 — Improve INP: break long tasks, defer non‑critical code, lazy‑init heavy widgets; re‑profile interactions in DevTools.

Day 7 — Stabilise CLS: set explicit sizes or aspect‑ratios (set correct dimensions), reserve space for late‑loading UI, and run cross‑device QA.

Days 8–9 — Roll out to sibling templates. Apply the same fixes to similar templates. Release with version control and a rollback plan. Then watch field trends in CrUX.

Day 10 — Business check‑in: review lead‑conversion rate on the pages you changed and form‑error logs. If you run paid traffic, check CPA. Finalise the next sprint backlog.

Want a sequenced backlog? We’ll map a first‑pass plan tailored to your stack.

How Do I Prove Business Impact from Core Web Vitals Work?

Track lead‑conversion rate on optimised pages as part of your website optimisation work and form‑error rates as early signals. Watch influenced pipeline and CPA if paid traffic lands there. If landing page experience improves, Google Ads Quality Score components (Expected CTR, Ad Relevance, Landing Page Experience) can reflect that. This may support efficiency. Attribute with UTMs, lead tracking and CRM mapping.

What If My Field Data (CrUX) Lags Behind Improvements?

Field data is a 28‑day rolling window of real user visits and updates daily, so improvements appear gradually. Keep shipping fixes, confirm lab wins, and let CrUX catch up as traffic returns. Use your lab tests and field data during rollout.

Common Pitfalls That Stall Website Optimisation

  • Fixing lab warnings without checking field impact.
  • Shipping big changes without a rollback or cross‑device QA.
  • Optimising a single URL instead of the template that powers many pages.
  • Ignoring an 800‑KB hero image while chasing small JS tweaks.

Tooling & Where to Look

  • Search Console → Core Web Vitals (field data, URL groups, mobile/desktop).
  • PageSpeed Insights → field + Lighthouse diagnostics per URL.
  • DevTools → Performance panel (long tasks), Coverage (unused JS/CSS).
  • web.dev playbooks for top CWV improvements.

Use these tools to steer your website optimisation roadmap and report progress clearly.

Make Your Next 10 Days Count

If your team can run the 10-day quick-strike now, pick one high-value template and ship. Next, wire up attribution so website optimisation wins show in reporting. Set up lead tracking software and connect it to CRM and database management to route leads cleanly and remove duplicates. If a template holds you back, explore a targeted website design before you chase micro-gains.

Finally, if you want a faster route with guardrails, Book a Free Website Audit and we’ll baseline Core Web Vitals and deliver a ranked backlog with expected impact.