Lighthouse score 90+: how to truly optimise in 2026

Lighthouse score above 90 separates optimised from mediocre sites. Google uses Core Web Vitals as ranking factor, and Lighthouse is the proxy. Here's how to go from 50 to 90+ in 2-4 weeks.

The 4 metrics that matter

• LCP (Largest Contentful Paint): <2.5s good, <1.8s great
• FID/INP (Interaction to Next Paint): <200ms good
• CLS (Cumulative Layout Shift): <0.1 good
• TTFB (Time To First Byte): <600ms good, <200ms great

The 5 fixes that move the score

1. Image optimization: WebP/AVIF, lazy load, srcset (see dedicated article). +15-25 points.
2. Critical CSS inline: only above-the-fold CSS inline, rest async. +5-10 points.
3. Defer non-critical JS: defer or async on scripts. +5-10 points.
4. Font display swap: font-display: swap avoids invisible text flash. +3-5 points.
5. Aggressive cache: 4h HTML cache via CDN, 1 year assets. +5-15 TTFB points.

Recommended free tools

• PageSpeed Insights: for "Google's" Lighthouse score
• WebPageTest.org: more detailed, different devices
• Chrome DevTools Lighthouse: local test
• GTmetrix: history over time, competitor monitor

Optimal intervention order

1. Week 1: image optimization (max impact, min effort)
2. Week 2: CDN cache setup
3. Week 3: defer JS + critical CSS
4. Week 4: measure, A/B, fine-tune

Lighthouse 90+ included in Conversion Site and Commerce web packages. For free audit: request audit.

Want to apply this to your SME?

If you'd like a concrete analysis of your situation, request the free audit from Gamerbit. In 48 hours we tell you exactly where you're losing leads, time or budget — no sales pitch.

For a complete system, the 2026 no-brainer offers are the most direct starting point.