A slow website costs you customers quietly. People do not complain; they just press back and try the next result. On mobile data, every extra second matters.
This guide explains how to check your speed, what the numbers mean, and the most common reasons a site is slow, in plain language.
Step 1: Measure it properly
Do not judge speed only on your office Wi-Fi. Use Google's free tool PageSpeed Insights (pagespeed.web.dev). Enter your website address and look at the mobile results first, because that is how most customers visit.
You will see a performance score and a section called Core Web Vitals. If your site has enough visitors, it also shows real-world data from Chrome users.
What Core Web Vitals mean
Google uses three main measurements for how a page feels to use:
- Largest Contentful Paint (LCP): how long until the main content, often the big image or heading, appears. Google considers 2.5 seconds or less good.
- Interaction to Next Paint (INP): how quickly the page responds when someone taps or clicks. 200 milliseconds or less is good.
- Cumulative Layout Shift (CLS): how much the page jumps around while loading, for example when an image suddenly pushes text down. 0.1 or less is good.
You do not need a perfect 100 score. Aim for good Core Web Vitals on mobile, and a site that feels quick when you try it on an ordinary phone.
The most common causes
1. Huge images
This is the number one cause we see. A photo straight from a phone camera can be several megabytes. The website shows it at a fraction of that size, but visitors still download the full file.
Fix: resize images to the size they are displayed, compress them, and use modern formats like WebP or AVIF. Load images further down the page only when the visitor scrolls to them ("lazy loading").
2. Too many plugins and scripts
Every slider, chat widget, popup, tracking code and social media feed adds code the browser must download and run. On sites built with page builders, it is common to find dozens of plugins, many unused.
Fix: remove what you do not need. For each script, ask: does this bring customers or information we actually use?
3. Slow or overloaded hosting
Very cheap shared hosting can put hundreds of websites on one server. If the server is slow to respond, everything else waits. A useful sign is a high "server response time" or "Time to First Byte" in PageSpeed Insights.
Fix: better hosting, caching, and a CDN (content delivery network) that serves your site from locations closer to your visitors.
4. Heavy themes and page builders
Multi-purpose themes are built to do everything, so they often load code for features you never use. Visual page builders can also add a lot of extra code to each page.
Fix: a lighter theme, cleaning up the builder output, or, for important sites, a custom build that only includes what the site needs.
5. Web fonts loaded badly
Using several font families, each in many weights, adds downloads. Fonts loaded from other servers can also delay text from appearing.
Fix: use one or two font families, only the weights you need, and host them with your site.
6. Autoplay videos and large sliders at the top
A full-screen video or a slider with five large images is often the first thing on the page, which makes it the slowest possible way to show your main content.
Fix: use a single optimised image, or load the video only after the page is visible.
Quick checklist
- Test your homepage on PageSpeed Insights, mobile tab.
- Check the size of the largest images on your homepage.
- List every plugin or third-party script, and remove the ones you do not need.
- Ask your host where your server is and what speed features they offer.
- Test again after each change, so you know what helped.
Why speed matters for SEO
Page experience is one of the many things Google considers, but the bigger effect is on people. A fast site keeps visitors reading, and more of them call, book or buy. Speed also makes your other marketing more effective, because fewer paid visitors leave before the page loads.
Need a faster website?
We build websites to load fast on mobile data from day one, and we can review an existing site and tell you honestly whether it can be fixed or needs rebuilding. See our web development service or email hello@auravestudio.com.