The verdict in three sentences
An SME website in Dublin with a 4.8 s LCP and a 420 ms INP on mobile loses leads every day: Google rates it "poor" and some visitors leave before the page appears. Fixing these Core Web Vitals costs 800 to 1,500 EUR for an audit and then 2,500 to 7,000 EUR of fixes (excluding VAT), over 3 to 5 weeks. The average observed gain is 15 to 30 % in conversion rate, which makes the work profitable within a few months for most B2B sites.
Understanding the thresholds and the gap to close
Core Web Vitals are three metrics measured on real visitors (CrUX data): LCP for how fast the main content appears, INP for responsiveness to clicks, CLS for visual stability. Google assesses the 75th percentile of visits, so slow phones weigh heavily.
| Metric | Good | Needs improvement | Poor | SME site |
|---|---|---|---|---|
| LCP (main content) | 2.5 s or less | 2.5 to 4 s | over 4 s | 4.8 s |
| INP (responsiveness) | 200 ms or less | 200 to 500 ms | over 500 ms | 420 ms |
| CLS (stability) | 0.1 or less | 0.1 to 0.25 | over 0.25 | 0.18 |
| Homepage weight | under 1.5 MB | 1.5 to 3 MB | over 3 MB | 5.6 MB |
| Active WordPress plugins | under 15 | 15 to 30 | over 30 | 38 |
Typical causes of such a profile: uncompressed 1 to 3 MB JPEG images, a heavy page builder, 6 to 10 third-party scripts (chat, ad pixels, maps), fonts loaded without preloading and shared hosting at 5 EUR a month.
Optimise the existing WordPress or rebuild: the comparison
The real decision is economic, not technical. If the site is under 4 years old with a still-valid design and a reasonable theme, optimisation is enough. If it relies on a heavy builder and an ageing codebase, you end up paying twice.
| Criterion | WordPress optimisation | Performance rebuild |
|---|---|---|
| Initial audit | 800 to 1,500 EUR | 800 to 1,500 EUR (often included) |
| Cost of work | 2,500 to 7,000 EUR | 8,000 to 18,000 EUR |
| Timeline | 3 to 5 weeks | 8 to 12 weeks |
| Expected mobile LCP | 2.2 to 2.8 s | 1.2 to 2 s |
| Expected INP | 150 to 250 ms | under 150 ms |
| Durability | 12 to 24 months with discipline | 3 to 5 years |
| Risk | Regression with each new plugin | Content and SEO migration |
Common fixes, by order of return: converting images to AVIF or WebP at the right dimensions (1 to 2 s LCP gain), moving to fast hosting with server cache and CDN (30 to 60 EUR a month), removing or deferring third-party scripts, replacing redundant plugins, preloading the font and hero image, trimming the page builder's JavaScript.
Plan and deliverables over 3 to 5 weeks
| Week | Work | Deliverable |
|---|---|---|
| 1 | CrUX and Lighthouse audit, script and plugin inventory | Prioritised report with estimated gains |
| 2 | Images, hosting, cache, CDN | LCP under 3 s in staging |
| 3 | Third-party scripts, JavaScript, fonts | INP under 250 ms |
| 4 | Visual stability, multi-device testing | CLS under 0.1 |
| 5 | Production release, real-user monitoring | Tracking dashboard |
Mind the measurement lag: the CrUX data Google uses covers a rolling 28 days. Green status in Search Console therefore shows up 4 to 6 weeks after release, even if lab tests look good immediately.
Mini case study
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
Ciarán, managing director of an industrial maintenance SME in Dublin, gets 3,200 visits a month with a 1.2 % visit-to-enquiry rate, so 38 enquiries. He orders a 1,100 EUR audit and 4,600 EUR of fixes, 5,700 EUR excluding VAT in total, plus hosting at 45 EUR a month.
After 2 months, mobile LCP drops to 2.3 s and INP to 180 ms. With a cautious 20 % conversion gain, the site produces 46 enquiries a month, 8 more. If 15 % become contracts worth 3,500 EUR in gross margin, that is about 4,200 EUR of margin per month. The investment is covered in under 2 months.
FAQ
How much does it cost to fix the Core Web Vitals of an SME website?
Between 3,300 and 8,500 EUR excluding VAT in 2026, audit included. The audit alone costs 800 to 1,500 EUR and prices the fixes precisely.
Do Core Web Vitals really affect rankings?
They are part of Google's page experience signals, acting mostly as a tie-breaker between equivalent pages. The most measurable effect is on conversion, often 15 to 30 % better.
Do we have to leave WordPress to get a fast site?
No, a well-built WordPress site reaches a 2 to 2.5 s LCP. A rebuild is justified when the site relies on a heavy builder and more than 30 plugins.
How long before Search Console shows the effect?
Count 4 to 6 weeks after release, because Google uses 28 days of real-user data. Lighthouse scores improve from day one.
How do we stop the site slowing down again?
Maintenance at 80 to 150 EUR a month includes a monthly metrics check and approval of every new plugin or marketing script.
Let's scope your project. Send us your site address and conversion goals, and we will run a priced audit followed by a 2,500 to 7,000 EUR fix plan delivered in 3 to 5 weeks. 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.
