A slow website costs you visitors, conversions and search visibility. Google measures real-user experience with Core Web Vitals, and they are a useful, practical target for any site. This checklist explains each metric and the fixes that usually make the biggest difference.
The three metrics in plain language
- LCP (Largest Contentful Paint) — how quickly the main content (often a hero image or heading) appears. Aim for 2.5 seconds or less.
- INP (Interaction to Next Paint) — how quickly the page responds when someone clicks, taps or types. Aim for 200 milliseconds or less.
- CLS (Cumulative Layout Shift) — how much the layout jumps around while loading. Aim for 0.1 or less.
Check your real-user data in Google Search Console (Core Web Vitals report) and PageSpeed Insights. Lab tools like Lighthouse are great for debugging, but field data is what counts.
Checklist: improve LCP
- Use fast hosting and a CDN; reduce server response time (TTFB).
- Serve images in WebP or AVIF and size them correctly for each screen.
- Do not lazy-load the hero image; preload it instead.
- Remove render-blocking CSS and JavaScript; inline critical CSS.
- Self-host or preconnect web fonts and use
font-display: swap. - Enable page caching (full-page cache for WordPress/WooCommerce).
Checklist: improve INP
- Audit third-party scripts — chat widgets, trackers and pop-ups are common culprits.
- Delay non-essential scripts until after the page is interactive.
- Break up long JavaScript tasks; avoid heavy work on click handlers.
- Remove unused apps (Shopify) and plugins (WordPress) that inject scripts.
- Keep the DOM size reasonable — huge mega-menus and sliders add up.
Checklist: improve CLS
- Always set
widthandheight(or aspect-ratio) on images and videos. - Reserve space for ads, embeds and cookie banners.
- Avoid inserting content above existing content after load.
- Use font fallbacks with similar metrics to reduce text reflow.
Platform-specific tips
WordPress & WooCommerce
Use a lightweight theme, a good caching plugin, object caching (Redis) for stores, and remove page-builder bloat where possible. Keep PHP up to date — newer versions are noticeably faster.
Shopify
Review installed apps and remove leftover code from uninstalled ones. Use Online Store 2.0 sections, compress images and limit the number of fonts and sliders on the home page.
Custom applications
Add HTTP caching headers, compress responses with Brotli, optimise database queries and consider server-side rendering for key landing pages.
Make speed a habit
Performance is not a one-time project. New apps, marketing scripts and content slowly add weight. Review Core Web Vitals monthly and set a "performance budget" for new features.
Want a faster site without breaking anything? See our speed optimization service or request a free speed review.