Why Is My Website So Slow, and Is It Costing Me Sales?

Imagine you’re going shopping for, let’s say, a new mobile phone. You do your research, compare makes and models, make your decision, head off to your local phone shop… and then the door takes five minutes to open. Meanwhile you’re standing outside with your card in your hand, ready to buy, but with no way to do so. Fed up, you head down the road to a competitor and spend your money there instead.

That’s what a slow website does to your customers. Whether they’re at the ready-to-buy stage or still doing their research, if your website or purchase journey is effectively a closed door, they’re going to take their business elsewhere. Online shoppers are even less patient than those in physical stores – even a two or three-second delay can make a huge difference when it comes to completing an online purchase… or not.

In this guide, I’m going to offer you a non-technical guide to understanding website speed, its impact on your sales and SEO, how to test it and, most importantly, how to fix it.

Why Website Speed Matters

Higher conversion rates

Today’s online buyers expect instant gratification. The second they click, the clock is ticking, and the longer your pages take to load, the less patient your visitors become. Slow load times have a direct impact on conversion. In a 2026 study, Shopify found that conversion rate dropped around 3.5% for every 100ms longer a site took to load.

Faster loading = improved trust

Quite apart from the fact that a slow website is frustrating, a fast one is seen as a sign of trust. If they can do what they need to easily and quickly, the chances are your users will return. In a 2025 survey, Clutch found that 48% of users will wait 10 seconds or less before they give up on a website.

Organic search

Page speed matters for SEO too. Google considers site performance and user experience within its algorithm in its bid to deliver the best and fastest results possible. It explicitly evaluates websites using a set of real-world user experience metrics known as Core Web Vitals. These three metrics, which we’ll explore in more detail further down, measure how fast main content loads, how quickly the page responds to clicks and whether page layouts jump around unexpectedly while loading. Offering a fast, stable experience can therefore give you an edge over your slower competitors.

Mobile-first indexing

Google will use the mobile version of your website for indexing and ranking. Because mobile devices often rely on data and network speed and have less processing power than desktop computers, poorly-optimised images and heavy scripts will hit mobile users hardest. If your site is sluggish on a mobile device, your visibility on Google search results pages is likely suffer accordingly.

What “Slow” Really Means (and How Google Measures It)

A slow website might mean different things to different users, whether that’s a second’s delay when clicking on a button, images taking a long time to load, or being unable to scroll down until certain elements are loaded. Modern websites are complex, often loading multiple plugins, fonts, images and other resources at the same time. So website performance is more than just about measuring speed. It’s also about how responsive and stable your pages feel when they’re loading.

What is a good page load time?

As a general rule of thumb, a total load time of 2 seconds or less is considered good. But this might not tell the whole story. Google recognises that actually a page could be still loading JavaScript in the background, but meanwhile a user perceives the page as fully loaded and interactive. And that’s where Core Web Vitals come in

Google’s Core Web Vitals

Google has its own set of metrics that it uses to measure page performance, called Core Web Vitals (CWV). There are three metrics, each measuring a different element of page load. They are also a ranking factor, so improving the performance of your website for these metrics will benefit not just your user experience, but potentially your SEO as well. Interestingly, a 2025 study by web performance optimisation company Yottaa found that fewer than 50% of websites actually meet Core Web Vitals!

Why Are Some Websites Slower than Others?

If you’ve ever wondered why your own site seems to drag while competitors load instantly, the answer usually comes down to hidden technical debt. Most websites don’t start out slow; they get weighed down over time by inefficient design choices, un-optimised media and outdated infrastructure.

Oversized and uncompressed images

Images are usually the biggest resources on any given webpage, and for most websites, high-quality photos are a must. But lovely crisp, hi-res images often mean lovely big file sizes, and that’s where your pages slow down. If a file size is 5MB or larger, it forces your visitor’s browser to download a mountain of data before displaying the page.

This issue is especially critical for your hero image (the large banner photo at the top of each of your pages). Because it’s usually the Largest Contentful Paint (LCP) element on the page, an un-optimised hero image will instantly ruin your Core Web Vitals score. Bonus points (or not!) if it’s a massive video file.

Bloated page builders and plugins

Platforms like WordPress make building websites accessible, but heavy drag-and-drop page builders (for example unoptimised Elementor or Divi setups) can generate huge amounts of unnecessary code (known as “code bloat”).

Additionally, every plugin you install will add its own JavaScript, CSS stylesheets and database queries. Even if a plugin isn’t actively displaying anything on a specific page, it will often load code across your entire site anyway, creating massive “render-blocking” delays while the user’s browser tries to process dozens of competing files.

Cheap, shared hosting

While it can be cost-effective when you launch, shared hosting means your website shares CPU processing power and memory with thousands of other websites on the same server.

If another site on that shared server experiences a traffic spike or gets infected with malware, your site’s performance tanks. Cheap hosting just doesn’t have the resources to process database queries quickly during busy periods.

Missing technical foundations (caching and CDNs)

When a visitor requests a page on a standard dynamic website, the server has to build that page from scratch: querying the database, assembling HTML and fetching the styles. Without proper performance architecture, your server repeats this heavy computational work for every single visitor. Caching avoids this by storing temporary copies of assets on either the browser or server, so they can be loaded more quickly the next time.

• No caching: Lacking page or object caching means your site can’t serve pre-built static versions of pages to visitors, causing high server response times (Time to First Byte).
• No content delivery network (CDN): Without a CDN (like Cloudflare), a visitor browsing your site in Australia has to fetch files directly from your primary server in the UK, creating an unavoidable time lag

Outdated technology (old PHP versions)

Most WordPress sites run on PHP, which is a backend scripting language that processes server requests. Newer versions of PHP execute code significantly faster and handle memory much more efficiently than older ones.

If your host or site is running on outdated PHP (anything older than PHP 8.1+), your server will be executing tasks at a much slower speed than it could be. Upgrading PHP is one of the most effective ways to instantly speed up backend execution without changing a single line of content.

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How to Check Website Speed

Before you call in your developer to fix any issues, you need to check how fast your pages are actually loading. Thankfully, there are several free, industry-standard tools you can use for this!

Google Pagespeed Insights

Google’s tool for checking page performance is really helpful for getting a general overview of how your pages are doing. It analyses your page and provides a performance score from 0 to 100 for both mobile and desktop, alongside direct feedback on your Core Web Vitals. Because this is Google’s own tool, it gives you a direct look at how its algorithms view your site.

Chrome Dev Tools & Lighthouse

A built-in tool inside the Google Chrome browser, which you can access by right-clicking any webpage and selecting Inspect > Lighthouse. If you’re a bit more tech-savvy, this will let you run instant synthetic audits directly from your own browser without leaving the page.

GTMetrix

A popular third-party site, GTMetrix breaks down loading performance into visual waterfalls and actionable charts. It shows you total page size, number of requests, and exactly which images or scripts are delaying load times.

Lab Data vs Field Data

When you run a test on Google PageSpeed Insights, you will often see two sets of metrics: Field Data and Lab Data. Understanding the difference is important for interpreting your results:

How to Fix Slow Page Speeds

Not every page speed optimisation needs a team of developers to fix. There are a few quick wins that you or your marketing team can implement, before you move on to the deeper, more technical aspects that require dev support.

Optimise images

As we saw above, a very common cause of pages being slow to load is large or poorly-optimised images. Fortunately, this is something that you or your team can fix without dev support. Using a plugin (like Smush) or similar third party tool such as TinyPNG, you can reduce your image file sizes without sacrificing image quality.

Convert images to new file formats

You should also consider saving your images in one of the next generation file formats designed to make file sizes smaller without losing quality, such as WebP and AVIF. There are plenty of free tools online that can help you convert your JPG or PNG images to these new formats.

Enable lazy loading for below the fold images

Configure your site so images below the initial screen view only load as the user scrolls down to them, preserving bandwidth for the initial page render.

Install a quality caching plugin

On platforms like WordPress, you can install a premium caching plugin (such as WP Rocket), which will instantly create pre-rendered static HTML copies of your pages, reducing processing strain on your server.

Audit and remove unused plugins

You should deactivate and delete any plugins, widgets or tracking scripts that are no longer actively used to eliminate unnecessary background code.

Beyond that, here’s where you likely will need to call your dev. The following tasks involve editing core theme files or altering server architecture and should be handled by an experienced web developer:

Refactoring unoptimised page builders

Get rid of bloated drag-and-drop page builder structures (such as heavy Elementor or Divi setups) and replace them with clean, lightweight Gutenberg blocks or custom code.

Eliminating render-blocking CSS & JavaScript

Your developer will configure your site to defer non-essential scripts and inline-critical CSS, so the browser can render visual elements on screen without waiting for heavy background files to download.

Configuring a global CDN & server infrastructure

Your developer can set up a Content Delivery Network (like Cloudflare Enterprise) to serve static assets from edge locations worldwide, alongside migrating your database to high-performance dedicated or managed cloud hosting.

Updating PHP and server environments

Upgrade backend server architecture to PHP 8.1+ and configure object caching (such as Redis or Memcached) to accelerate database query speeds.

Conclusion

So, to answer the questions in the title of this post:

• Your website is slow because of unoptimised images, unmanaged content delivery or technical debt
• Yes, it absolutely is costing you sales

The good news is that page speed is actually one of the most fixable aspects of modern web design. By measuring your site’s Core Web Vitals, trimming bloat and investing in a solid technical architecture, you can transform a sluggish site into a sales powerhouse.