Core Web Vitals have been a confirmed Google ranking signal since 2021, with INP replacing FID in March 2024. These answers cover what's actually true in 2026 — not the 2022 articles still cluttering search results.
1. **What is INP and how do I fix poor INP scores?** — Interaction to Next Paint — measures how quickly your page responds to user input. Should be under 200ms (good) or under 500ms (acceptable). Replaced FID in March 2024. Most pages with poor INP have heavy JavaScript event handlers or excessive third-party scripts blocking the main thread.
2. **How do I fix a poor Largest Contentful Paint (LCP) score?** — LCP should be under 2.5 seconds on mobile. Five fixes that work for 90% of sites: (1) optimize and preload your hero image, (2) eliminate render-blocking resources above the fold, (3) use a CDN, (4) enable HTTP/2 or HTTP/3, (5) reduce server response time (TTFB) under 600ms.
3. **What's a good Core Web Vitals score in 2026?** — All three metrics in the 'Good' threshold (LCP <2.5s, INP <200ms, CLS <0.1) at the 75th percentile of mobile users over the trailing 28 days. About 40% of websites achieve this in 2026 — passing all three is a meaningful competitive edge.
4. **Lab vs field data — which one does Google actually use?** — Field data (real user measurements) is what Google uses for ranking. Lab data (synthetic Lighthouse runs) is for debugging only. A site can have perfect Lighthouse scores and still fail Core Web Vitals if real users experience poor performance.
5. **Why does my React/Vue/Angular SPA have poor Core Web Vitals?** — SPAs ship large JavaScript bundles that block the main thread during hydration. The browser must download, parse, compile, and execute the bundle before the page becomes interactive. Solutions: code-splitting, server-side rendering, partial hydration, or migrating to a meta-framework (Next.js, Nuxt, Remix, Astro).
6. **How do I fix Cumulative Layout Shift (CLS)?** — Set explicit width and height attributes on all images, embeds, and ads. Reserve space for dynamic content with min-height. Avoid injecting content above existing content. Most CLS issues come from images, web fonts, and ads loading without reserved space.
7. **Which CDN should I use for Canadian audiences?** — Cloudflare for most use cases (free tier sufficient for many businesses, $20/month Pro for serious sites). BunnyCDN for cost-sensitive scenarios. Fastly for advanced customization. AWS CloudFront if you're already deep in AWS. All major CDNs have Canadian PoPs (Toronto, Montréal, Vancouver) — choose based on features, not geography.
8. **Does Google use mobile or desktop Core Web Vitals for ranking?** — Mobile, primarily — Google has been mobile-first indexing since 2023, and mobile field data is the basis for the Core Web Vitals ranking signal. Desktop CWV is reported in Search Console for diagnostic purposes but isn't the primary ranking input.
Every answer in this collection was written or reviewed by Martin Vassilev, who has been working in SEO, web design, and digital marketing for over 12 years. The answers reflect what's actually true in 2026 — not 2018 best-practice articles regurgitated for SEO. If you find anything inaccurate or outdated, email us and we'll update it (and credit you).
Interaction to Next Paint — measures how quickly your page responds to user input. Should be under 200ms (good) or under 500ms (acceptable). Replaced FID in March 2024. Most pages with poor INP have heavy JavaScript event handlers or excessive third-party scripts blocking the main thread.
LCP should be under 2.5 seconds on mobile. Five fixes that work for 90% of sites: (1) optimize and preload your hero image, (2) eliminate render-blocking resources above the fold, (3) use a CDN, (4) enable HTTP/2 or HTTP/3, (5) reduce server response time (TTFB) under 600ms.
All three metrics in the 'Good' threshold (LCP <2.5s, INP <200ms, CLS <0.1) at the 75th percentile of mobile users over the trailing 28 days. About 40% of websites achieve this in 2026 — passing all three is a meaningful competitive edge.
Field data (real user measurements) is what Google uses for ranking. Lab data (synthetic Lighthouse runs) is for debugging only. A site can have perfect Lighthouse scores and still fail Core Web Vitals if real users experience poor performance.
SPAs ship large JavaScript bundles that block the main thread during hydration. The browser must download, parse, compile, and execute the bundle before the page becomes interactive. Solutions: code-splitting, server-side rendering, partial hydration, or migrating to a meta-framework (Next.js, Nuxt, Remix, Astro).