Page Load Speed Optimization: how to Improve Performance

Fast performance isn't an option for today’s web users. Everyone expects instant loading, and Google has already warned that poor site performance may result in bad ranking positions. It doesn't matter if you have a blog, ecommerce store or business website; improving loading times and comprehending their significance is one of the best ways to invest in your online property.

Why page speed matters for SEO

Page speed was first introduced as a ranking signal by Google for desktop websites in 2010, and then in 2018 came the mobile version of this update, called Speed Update. It became increasingly important after that. This was confirmed by Google itself when John Mueller said, "Is speed a ranking factor? YES."

The correlation between page speed and ranking can be observed from the statistics provided. The average time it takes for a web page that ranks on the first page of Google’s search results to load is 1.65 seconds, whereas the average time for loading any other website is 3.21 seconds. Slow domains were found to score 3.7% lower than fast domains in searches on average.

There is an indirect effect on SEO from speed through user experience as well. A bounce occurs when users exit the website before it has had time to fully load, sending Google a message that it wasn't a good experience for the user. If a site takes more than three seconds to load, 40 percent of users will give up, and if it takes only one second to load, seven percent will bounce, while 38 percent will bounce after five seconds.

Core Web Vitals: Google's speed framework

In 2020, Google launched Core Web Vitals as metrics that are used to evaluate website performance from a user perspective. The metrics are recognized as ranking signals. There are three main metrics:

Largest Contentful Paint (LCP) measures how long it takes for the largest visible element on a page to load. A good LCP is under 2.5 seconds.
Interaction to Next Paint (INP) replaced First Input Delay in 2024 and measures the latency of all user interactions on a page, not just the first. A good INP is under 200 milliseconds.
Cumulative Layout Shift (CLS) measures visual stability, specifically how much page elements shift around during loading. A good CLS score is under 0.1.

On the bright side, the adoption process has been getting better. While only 39% of sites met the criteria back in 2022, by 2024 this number had increased to 50.5%. That being said, it also means that at least half of all the sites are failing to reach even Google's requirements, which can be a huge benefit for those who decide to take this issue into their hands.

Apart from improving the ranking of your website, meeting Core Web Vitals can greatly improve other metrics. In particular, people are 24% less likely to leave your site when it is loading.

How slow pages hurt your bottom line

However, the influence of page speed goes far beyond merely ranking better on search results pages. If you have a website for business, then the conversion figures should be particularly alarming.

For example, an e-commerce website that opens in one second can have a conversion rate of 3.05%. Conversely, those websites that open in five seconds can only achieve conversion rates of 1.08%. That translates to almost three times more potential income for four additional seconds. Additionally, for every additional second of mobile site load time, you might lose between 20% of sales.

The long-term reputational effects are also considerable. 79% of customers experiencing issues on your website will not visit your site again to make another purchase. Moreover, 44% of online buyers talk about their bad experiences with others.

What causes slow page load times

Before fixing a performance problem, it helps to understand what typically causes one. The most common culprits are:

Image optimization. Images that have not been optimized take up a lot of space and can slow down website performance.
JavaScript and CSS render blocking. Unoptimized scripts and stylesheets that load before the actual content on the page will cause the browser to wait for their download.
Website caching is off. With caching turned off, every visit requires the user to load all the resources on the page once again.
Time to first byte is high. This metric refers to the initial server response to any request from the visitor’s computer. It takes into account such factors as server quality and website design.
Too many third-party scripts. Third-party scripts include everything from social media widgets to analytics and advertisement scripts.
No content delivery network (CDN). Serving all assets from a single origin server means users far from that server experience significant latency.

How to improve your page load speed

Optimize Images

The size of images is normally the biggest contributor to the total weight of a webpage. Compress all images prior to uploading using online tools such as Squoosh, TinyPNG, and ImageOptim. The modern WebP format can provide better compression rates compared to older formats like JPEG and PNG without loss of image quality. Additionally, make sure you have utilized the srcset property to deliver appropriate images based on the screen size.

Minify Your CSS, JavaScript, and HTML Code

Minification is the process of removing extra characters from your files in order to reduce their size without altering their actual function. Most compilers perform this automatically as part of the build process. Another common practice is to combine several CSS and JS files to minimize the number of HTTP requests.

Enable Browser Caching

By setting proper cache control headers on your server, all static resources (e.g., images, fonts, and scripts) will be cached in the visitor’s browser. This will result in much faster loading times during subsequent visits since they will no longer need to request these assets from the server.

Employ the use of content delivery networks

The CDN will make copies of your static files available at various servers worldwide, thus serving the content from servers closest to your visitors. The CDN will minimize the loading time for international audiences, relieving your origin server of the pressure. CloudFlare, Fastly, and Amazon CloudFront are some of the widely-used services.

Defer non-critical JavaScript

Use the defer or async attributes on script tags to prevent JavaScript from blocking the initial render of the page. Scripts that are not needed until after the page loads, such as analytics or chat tools, should load last.

Upgrade your hosting

Shared hosting packages often present a constraint. A Time To First Byte of over 600 milliseconds is a clear sign that your server latency is to blame. You will notice an improvement just by switching from shared hosting to either managed hosting or a virtual private server.

Tools for measuring performance

You cannot improve what you do not measure. The following tools are free and widely trusted:

Google PageSpeed Insights analyzes your URL and provides separate desktop and mobile scores, along with specific recommendations ranked by impact.
Google Search Console includes a Core Web Vitals report showing how real users experience your pages across all URLs on your site.
GTmetrix provides waterfall charts that show exactly which resources are taking the longest to load and where the bottlenecks are.
WebPageTest allows you to test from specific locations and connection speeds, useful for understanding performance for users in different regions.

The bottom line

Page Speed is one of those rare topics in SEO where any changes made can have a direct effect on your website’s ranking and conversions. All you need to do is measure your site against some basic benchmarks, and if you don’t meet them, you will lose out on opportunities for your site to rank higher and drive more traffic and sales.

You can begin by performing an audit using PageSpeed Insights, start by fixing the low-hanging fruit, and then make page speed a regular priority when maintaining your website.