The verdict in three sentences
Core Web Vitals (LCP, INP, CLS) are both a Google ranking signal and a direct conversion factor: a slow site loses positions and leads. In 2026, the "good" thresholds are LCP < 2.5s, INP < 200ms, CLS < 0.1, and each extra second of LCP costs about 7% of conversions. An optimization project costs 2,000 to 6,000 EUR (about USD 2,200-6,600) and pays back within months on a high-traffic B2B site.
Understanding the three metrics and their 2026 thresholds
Since March 2024, INP has replaced FID. Here are the official thresholds and the most common causes we see in Singapore.
| Metric | Good | Needs work | Poor | Main cause |
|---|---|---|---|---|
| LCP (loading) | < 2.5s | 2.5 - 4s | > 4s | Heavy images, slow hosting |
| INP (interactivity) | < 200ms | 200 - 500ms | > 500ms | Excessive JavaScript |
| CLS (stability) | < 0.1 | 0.1 - 0.25 | > 0.25 | Images without dimensions, ads |
| TTFB (server) | < 0.8s | 0.8 - 1.8s | > 1.8s | Shared hosting, no cache |
On the B2B sites we audit in Singapore, a degraded LCP comes 7 times out of 10 from uncompressed images and shared hosting with no CDN.
The quantified business impact
Core Web Vitals are not just a Google whim: they hit revenue.
| Improvement | Measured effect | Estimate source |
|---|---|---|
| -1s of LCP | +7% conversions | 2026 order of magnitude |
| LCP 4s -> 2s | +15 to 20% page views | Estimate |
| INP < 200ms | -12% mobile bounce | Estimate |
| CLS < 0.1 | +5% form completion | Estimate |
| All-green pass | Avg gain 3-6 positions | Sector estimate |
Prioritizing the work and budget
You don't fix everything at once: attack the best gain/effort ratio first.
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| Task | Effort | LCP/INP gain | Indicative cost |
|---|---|---|---|
| WebP/AVIF image compression | Low | High | 500 - 1,200 EUR |
| CDN + server cache | Medium | High | 800 - 2,000 EUR |
| JS reduction / lazy load | Medium | High (INP) | 1,000 - 2,500 EUR |
| Font & LCP preload | Low | Medium | 400 - 900 EUR |
| Full technical rebuild | High | Very high | 4,000 - 6,000 EUR |
Measurement tools: PageSpeed Insights and CrUX (real field data), Lighthouse for lab tests, and the Search Console "Core Web Vitals" report.
Mini case study
Wei Lin, IT director of an industrial trading SME in Singapore, sees a mobile LCP of 4.8s and a 61% bounce rate. The site draws 18,000 visits/month and 90 quote requests. A 3,500 EUR project (WebP images, CDN, JS reduction) brings LCP to 2.1s. Result: bounce down to 49%, conversions +16%, i.e. 90 -> 104 requests/month. With an average deal of 4,200 EUR and a 20% close rate, those 14 extra requests represent 11,760 EUR of monthly revenue. The 3,500 EUR spend is recouped in under two weeks of full performance.
FAQ
Does Google really penalize a poor LCP? Yes, Core Web Vitals are a confirmed ranking factor, especially as a tiebreaker between pages of equivalent content. An LCP > 4s costs you on average 3 to 6 positions on mobile.
What's the difference between lab and field data? Lighthouse simulates (lab); CrUX measures your real visitors (field). Google relies on CrUX field data over 28 days; that's what you optimize, not an isolated Lighthouse score.
How long to see the SEO effect of an optimization? CrUX metrics update over a rolling 28-day window, so expect 4 to 6 weeks before Google factors in the improvement, plus a few more weeks for ranking gains.
Do I need a full rebuild or can I optimize what exists? In 70% of cases, targeted optimization at 2,000-3,500 EUR is enough. A full rebuild (4,000-6,000 EUR) is only justified when the technical base is obsolete or the CMS is unmanageable.
Is INP harder to optimize than LCP? Often yes, because INP depends on JavaScript and third-party scripts (chat, analytics, ads). Reducing blocking JS and deferring non-essential scripts usually brings INP below 200ms.
Let's scope your project. Send us your URL and PageSpeed scores: we frame a Core Web Vitals project (2,000-6,000 EUR) with quantified before/after targets and gain/effort prioritization. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
