CONVERSION LOSS PER SECOND
7%
per additional second of load time (Portent, 2023)
↑ compounds with every additional second
BOUNCE RATE INCREASE AT 3S
+68%
vs 1-second load time baseline
↑ 70% of paid traffic is affected at most SMB sites
MEDIAN SMB MOBILE LOAD
4.2 seconds
across small business websites (HTTP Archive, 2024)
↑ Google target is under 2.5s LCP
IMAGES AS PAGE WEIGHT
42%
of total page weight on average (HTTP Archive)
↓ biggest single quick-win category
What Actually Causes Slow Websites
The causes of slow websites are not mysterious. They are consistent across thousands of audits and fall into six categories — every one of which is fixable. The root cause for most SMB websites is not infrastructure cost, it is the accumulation of technical debt from unoptimised images, redundant plugins, and a hosting environment that was never designed for performance.
The most common scenario: a WordPress site with 40+ plugins, uncompressed hero images serving 3MB files to mobile visitors, shared hosting in a single geographic region, and no caching layer. Each issue is individually fixable. Together, they produce a 5–8 second LCP.
The Six Causes — And What Each Fix Costs
| Issue | Typical impact | Fix | Fix cost |
|---|---|---|---|
| Unoptimised images | +1.5–3s LCP | Convert to WebP / AVIF, lazy-load, serve via CDN | $200–$500 |
| No CDN / single-region hosting | +0.5–1.5s for remote visitors | Move to CDN-backed hosting (Vercel, CF Pages) | $0–$40/mo |
| Render-blocking scripts | +0.8–2s First Paint | Defer / async non-critical JS | $150–$400 |
| Heavy/redundant plugins | +0.5–2s LCP (WordPress) | Plugin audit + consolidation | $200–$600 |
| No page caching | +1–3s server TTFB | Enable caching at server and CDN | $0–$200 |
| Unminified CSS/JS | +0.3–0.8s parse time | Build-time minification (automatic in Next.js) | $0–$150 |
Most sites can move from 5s to under 2.5s LCP with $500–$1,500 of targeted fixes. No rebuild required for most cases.
How Core Web Vitals Affect Search Rankings
Since the 2021 Page Experience update, Google uses Core Web Vitals (LCP, CLS, INP) as direct ranking signals. A site in the bottom quartile for CWV is competing at a structural disadvantage in organic search — regardless of content quality and backlink profile. The cumulative organic traffic loss from sustained poor CWV performance over 12+ months is rarely quantified, but consistently underestimated.
The Agency Company runs a free performance benchmark that shows your current Core Web Vitals scores alongside the revenue impact calculation. It takes 30 minutes and produces numbers decision-makers can act on.
Sources
- Portent: Page Load Time Effects on Conversion 2023 (portent.com)
- HTTP Archive Web Almanac 2024 (almanac.httparchive.org)
- Google web.dev: Core Web Vitals documentation (web.dev/vitals)