The verdict in three sentences
A SaaS vendor website with a mobile LCP above 4 s loses both organic traffic and demo requests. A Core Web Vitals audit at EUR 1,200 to 3,500 followed by EUR 3,000 to 12,000 of fixes usually brings LCP under 2.5 s, INP under 200 ms and CLS under 0.1 within 4 to 8 weeks. On the B2B sites we track, the measured conversion uplift sits between 8 and 15%, which pays back the spend within a few months once an average contract is worth more than EUR 5,000.
What an INP and Core Web Vitals audit actually measures in 2026
Since March 2024, Google has replaced FID with INP (Interaction to Next Paint), which measures the responsiveness of every click, keystroke or menu opening across the whole visit. For a software vendor, the worst-hit pages are usually the pricing page (JavaScript calculator), the demo page (HubSpot or Calendly form) and a blog loaded with marketing scripts.
A serious audit combines two sources: CrUX field data (real Chrome users over 28 days) and lab measurements from Lighthouse and WebPageTest on a 4G mobile profile. The deliverable must rank fixes by impact and cost, not just list 80 warnings.
| Metric | Google "good" threshold | Typical pre-audit value | Common cause on a SaaS site |
|---|---|---|---|
| LCP (main content render) | < 2.5 s | 4.8 s mobile | 900 KB hero image, render-blocking font |
| INP (responsiveness) | < 200 ms | 420 ms | Tag manager with 14 tags, chat widget |
| CLS (visual stability) | < 0.1 | 0.24 | Cookie banner and images without dimensions |
| TTFB (server response) | < 800 ms | 1.4 s | Shared hosting, no caching |
| Homepage weight | < 1.5 MB | 4.2 MB | Autoplay video and unused libraries |
| Third-party scripts | < 8 | 19 | Marketing tools stacked over 5 years |
Audit and fix pricing: the 2026 grid
The figures below are 2026 ballpark rates for senior agencies and freelancers in Western Europe and the UK. They depend mainly on the number of page templates (not the number of pages) and on the stack: a WordPress site built with a visual page builder costs more to fix than a Next.js site.
| Service | Scope | Price excl. VAT 2026 | Timeline |
|---|---|---|---|
| Express audit | 5 templates, prioritised report | EUR 1,200 to 1,800 | 1 week |
| Full audit | 10 to 15 templates, CrUX + lab + third parties | EUR 2,500 to 3,500 | 2 weeks |
| Quick fixes | Images, fonts, caching, lazy loading | EUR 3,000 to 5,000 | 2 to 3 weeks |
| Deep fixes | JS refactor, tag manager, server rendering | EUR 6,000 to 12,000 | 4 to 6 weeks |
| Monthly monitoring | CrUX tracking + regression alerts | EUR 250 to 600/month | Ongoing |
| Stack migration | Move to Next.js or headless | EUR 15,000 and up | 8 to 12 weeks |
The prioritisation that works best follows this order: first TTFB and caching (instant gain on every page), then the LCP image and fonts, then the third-party script audit that drags INP down, and finally CLS. Removing 6 unused marketing tags often gains more than two weeks of code optimisation.
Before and after: what you can reasonably expect
| Measure | Before | After 6 weeks | Change |
|---|---|---|---|
| Mobile LCP (CrUX p75) | 4.8 s | 2.1 s | -56% |
| INP (p75) | 420 ms | 160 ms | -62% |
| CLS | 0.24 | 0.04 | -83% |
| Mobile bounce rate | 63% | 49% | -14 points |
| Demo requests / month | 52 | 58 | +12% |
| Organic traffic (at 3 months) | -18% year on year | +9% | Gradual recovery |
Core Web Vitals remain a secondary ranking signal compared with content relevance. The traffic gain comes mostly from better experience (fewer bounces, more pages per visit); the conversion gain is direct and measurable within 30 days.
Mini case study
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
James, marketing lead at a 45-person HR software vendor in London, receives 52 demo requests per month. His close rate is 12% and an annual contract is worth EUR 7,800 on average, roughly EUR 48,700 of signed revenue per month coming through the website.
He orders a full audit at EUR 2,900 and fixes at EUR 7,400, so EUR 10,300 in total. After the fixes, requests rise to 58 per month (+12%). Six extra demos at a 12% close rate means 0.72 extra contracts per month, about EUR 5,600 of additional monthly revenue. The spend is covered in just under 2 months of signed deals, before counting the organic traffic recovery.
FAQ
How long before Core Web Vitals turn green in Search Console?
CrUX data is computed over a rolling 28 days. Allow 4 to 6 weeks after the fixes go live for Search Console to report "good" URLs.
Is INP really a ranking factor?
Yes, it has been part of the page experience signals since March 2024, but its weight is modest compared with content. Its most measurable effect is on conversion: an INP above 500 ms cuts form usage by 10 to 20% on the sites we audit.
Do we need to rebuild the website to fix Core Web Vitals?
Rarely. In 7 cases out of 10, targeted fixes under EUR 8,000 are enough. A stack migration is justified mainly when the WordPress theme or page builder makes every fix fragile.
Which tools should we use to track results?
PageSpeed Insights and Search Console are free and enough for monitoring. A RUM (real user monitoring) tool costs EUR 20 to 150 per month and detects a regression within 24 hours.
What does a good audit report contain?
A list of 10 to 25 actions ranked by impact, effort and estimated cost, with the affected templates. An 80-page report with no prioritisation does not help your team decide.
Let's scope your project. Send us your website URL and we will price the Core Web Vitals audit, an indicative fix budget (EUR 3,000 to 12,000) and the time needed to get back to green. 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.
