Website Speed and Core Web Vitals: Why Slow Sites Lose Leads (and How to Fix Them)

Every extra second your website takes to load is a second for a visitor to hit the back button and call someone else. Speed affects how people feel about your business, how many of them become leads and — through Google’s Core Web Vitals — how your pages perform in search.

Here’s a practical guide to what matters, how to measure it and what to fix first.

What are Core Web Vitals?

Core Web Vitals are three measurements Google uses to describe real-world user experience. Google’s web.dev documentation sets these “good” thresholds:

• Largest Contentful Paint (LCP) — 2.5 seconds or less. How long it takes for the main content (usually the hero image or headline) to appear.
• Interaction to Next Paint (INP) — 200 milliseconds or less. How quickly the page responds when someone taps or clicks.
• Cumulative Layout Shift (CLS) — 0.1 or less. How much the layout jumps around while loading.

Google measures these from real Chrome users visiting your site, mostly on phones — so a site that feels fast on your office Wi-Fi can still be slow for customers on mobile data.

How to check your website speed

• PageSpeed Insights — enter any URL to see real-user data (when available) and a lab test with suggestions.
• Google Search Console → Core Web Vitals report — shows groups of pages that pass or need work.
• Your phone — open your site on mobile data, not Wi-Fi, and watch what happens.

Test your most important pages, not just the homepage: service pages, landing pages for ads, and your contact or booking page.

The fixes that usually make the biggest difference

1. Optimise images

Oversized images are the most common cause of slow pages. Resize images to the size they’re displayed at, use modern formats such as WebP or AVIF, compress them, and lazy-load images below the fold. Don’t lazy-load the main hero image — load it with high priority instead.

2. Cut unnecessary plugins, apps and scripts

Each chat widget, slider, tracking pixel, popup and social feed adds code. Audit what’s installed and remove anything that isn’t earning its place. On Shopify and Wix, uninstall unused apps; on WordPress, deactivate and delete unused plugins.

3. Use caching and a CDN

Caching serves pre-built pages instead of rebuilding them for every visitor, and a content delivery network (CDN) serves files from locations close to your visitors. Hosted platforms like Shopify, Wix and Webflow include a CDN; on WordPress, good hosting plus a caching plugin does the job.

4. Load fonts efficiently

Use fewer font families and weights, host fonts efficiently and use font-display: swap so text appears immediately.

5. Reserve space for images, embeds and ads

Layout shift happens when something loads and pushes content down. Set width and height on images and video, and reserve space for embeds and banners.

6. Reduce heavy JavaScript

Slow interactions (poor INP) usually come from too much JavaScript running at once. Defer non-essential scripts, avoid heavy page builders’ unused features and be selective with animation libraries.

7. Choose good hosting

For WordPress, cheap shared hosting is often the bottleneck. A quality host with modern PHP, server-level caching and enough resources makes everything else easier.

Speed is only half the story — clarity converts

A fast page that doesn’t explain what you do, who you help or what to do next still won’t produce leads. Pair speed work with clear headlines, visible phone numbers, short forms and proof such as reviews and project photos. That’s the approach we take in every website design project.

Quick speed checklist

• Compress and resize images; use WebP/AVIF
• Don’t lazy-load the hero image; do lazy-load the rest
• Remove unused plugins, apps and scripts
• Use caching and a CDN
• Limit font families and weights
• Set image and embed dimensions to avoid layout shift
• Defer non-essential JavaScript
• Re-test key pages on mobile after every change

Want us to look at your site? Request a free quote and mention “speed audit”.