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How to Speed Up a WordPress Site

Feb 17, 2025
13 min read
author sona

Sona Hakobyan

Speed.. It’s not just for cars and athletes; your website needs it too. We know nothing is more frustrating than clicking on a link and waiting…and waiting…for the page to load. If you’re tired of your WordPress site dragging its feet, you’re in the right place.

In this guide, we’ll tackle one of the most concerning questions: how do you speed up a WordPress website? That’s exactly what we’re here to explore. From practical WordPress speed optimization tips to advanced WordPress performance tuning strategies, this guide will help you transform your site’s speed and overall performance.

So, grab a cup of coffee (or tea, no judgment), and let’s dive into the simple tweaks and smart strategies that can turn your sluggish site into a speedster. 

P.S. After reading the first part of this article, we suggest you enjoy the second part, which presents a real case of WordPress website speed optimization.

Why Do WordPress Websites Slow Down?

Websites are getting heavier every year, and WordPress sites are no exception. To understand this trend, let’s look at some key data and the underlying issues contributing to slow-loading pages.

The Growing Size of Web Pages

The size of web pages has grown significantly over the last decade. According to httparchive.org, the median desktop page weight and mobile page weight has increased. 

Today, mobile pages are nearly as heavy as desktop pages, meaning users expect mobile networks and devices to deliver the same experience as desktops, an expectation that is often unmet.

This growth is driven by several factors:

  • Increasing use of high-resolution images and videos.
  • Overloaded websites with non-optimized content.
  • More complex code and third-party integrations.
growing size of web pages statistics

WordPress is a versatile platform, but its flexibility can sometimes lead to performance issues. Here are the most common reasons WordPress sites experience slow loading times:

  • Too many plugins: WordPress plugins can add functionality, but each one introduces additional scripts, stylesheets, and database queries. Overloading your site with unnecessary or poorly optimizedg plugins can significantly slow it down.
  • Non-optimized images: High-resolution images without proper compression can add excessive weight to your pages. This is one of the biggest culprits for slow-loading WordPress sites.
  • Outdated themes and plugins: Using outdated themes or plugins can lead to performance bottlenecks, especially if they contain errors or compatibility issues.
  • Inefficient hosting: Shared hosting environments, often chosen for their affordability, can struggle to handle high traffic or complex WordPress sites, resulting in slower speeds.
  • Lack of caching: Without caching, WordPress dynamically generates pages every time a user visits, which takes longer than serving pre-generated pages.
  • Bloated code: Many WordPress themes and plugins come with excessive or redundant code that bogs down your site. Customizing or cleaning up this code can help.
  • Excessive HTTP requests: Each element on your WordPress site (images, CSS, JavaScript) requires an HTTP request. Too many requests can slow down loading times.
  • Unoptimized databases: WordPress databases can become bloated with unnecessary data over time, such as old revisions, spam comments, and transient options.
Explore how site speed can transform your conversions—read more on our blog: site speed impact on conversion!

Why Should You Speed up WordPress Site?

A fast WordPress site doesn’t just increase WordPress speed; it also helps improve overall user experience, SEO rankings, and conversions. By focusing on strategies that improve WordPress performance, you can ensure your site stays competitive and delivers a seamless browsing experience

ReasonImpact
Improved User ExperienceVisitors expect pages to load in under 3 seconds. Slow sites frustrate users, leading to higher bounce rates.
Higher Search RankingsGoogle considers page speed a ranking factor. A faster site improves your SEO and increases visibility.
Better Conversion RatesStudies show faster websites boost conversions, with every second of delay costing potential leads and sales.
Reduced Bounce RatesUsers leave slow sites quickly. Faster loading pages keep visitors engaged and exploring.
Mobile-Friendly PerformanceSpeed is critical on mobile devices, where users expect quick and seamless browsing.
Competitive EdgeA faster website gives you an advantage over slower competitors, keeping users on your site instead of theirs.

Key Statistics to Consider

  • 53% of mobile users abandon a site if it takes longer than 3 seconds to load.
    (Tooltester)
  • A 1-second delay in page loading results in a 7% drop in conversions.
    (Blogging Lift)
  • Sites that load within 2 seconds tend to have the lowest bounce rates. (Blogging Lift)
how to speed up a website

What Is a Fast Website?

Your first question might be, “What is a fast website or app?” The table below shows different levels of response to the system interface.

Response delay, millisecondsUser perception
0-100Instant response
100-300A small but noticeable delay
300-1000The system works, but it is overloaded
1000-10000Likely switching thoughts to other tasks
10000 and moreThe task is cancelled (the system does not work)

For example:

  • If your system responds in a time window of up to 100 milliseconds, a user will not notice a delay. 
  • Users start noticing delays at up to 300 milliseconds. When this limit is exceeded, they may become distracted and switch to another task. 
  • If the delay exceeds 10 seconds, a user may discard the task, forget about it, or do something else. This means that he or she will close the website tab.

If your potential customers have e-commerce projects, they may have multiple tabs open at the same time with different contractors. Customers will just close the page that does not load quickly. They will not even care what offer was on the page. Content is secondary to loading speed. If customers do not see the offer, it simply does not exist for them.

If you want to test your website and know the load status, we recommend PFLB’s

Actual Website Loading Time

Actual speed is the real-world loading time your users experience. Measuring this helps you understand how your site performs under different conditions. Here are the tools you can use:

  1. 1.
    Web Analytics Tools
    Systems like Google Analytics or Yandex Metrica track:
  • Standard metrics: Average load times.
  • Custom metrics: Tailored data for specific pages or user actions.
  1. 2.
    Specialized Tools
    Advanced systems like Akamai mPulse collect detailed, real-user data. These tools provide insights into performance variations by device, location, and network speed.

Challenges in Analysis
Data will vary due to differences in devices (desktop vs. mobile) and network conditions. For instance, mobile users often face slower speeds. 

Synthetic Testing

In this paragraph, we take a look at synthetic testing, which is testing done on our terms. It consists of the server testing part and complex metrics, which we will discuss in more detail.

We recommend using JMeter, a remarkable load testing tool, to test server performance.

Complex metrics measure how a website behaves in a real browser, which is exactly what a client sees, including network parameters, device type. 

Tools like Lighthouse and WebPageTest provide insights into how to speed up WordPress website load time and improve WordPress performance by identifying key bottlenecks.

WebPageTest is a system that became open source in 2008. It is now actively maintained and developed. The system is big and contains many advanced features. 

Lighthouse is not a separate system but a subsystem of the Chrome browser that executes performance testing in the browser. That is, it loads and collects metrics and then generates reports. The system is much newer than WebPageTest; it was created only a few years ago and is being actively developed. Both systems work with the Chrome browser. 

Each system has two types of applications:

WebPageTest

  • Public: This is suitable for those who want to learn about the product and try it out.
  • Personal: You install the system on your device.

Lighthouse

  • Public: Chrome DevTools plug-in. 
  • Personal CLI: You use the command-line interface that performs tasks automatically.

WebPageTest

The WebPageTest system offers the following capabilities:

  • Distributed Architecture:
  • Servers
  • Agents
  • Operating System Support for Agents:
  • Windows, Linux, iOS, and Android
  • Real Device Testing: Enables testing on actual devices.
  • Channel Shaping: Allows control of parameters such as bandwidth, delays, and packet losses.
  • Data Collection:
  • TCPdump (a UNIX utility)
  • Screenshots (including video generation)

The system’s distributed architecture includes a server responsible for issuing tasks and responding to agents, which execute the tasks.

Most importantly, WebPageTest supports all major browsers: Edge, IE, Firefox, Chrome, and Opera. This is the main advantage of WebPageTest, as your audience most likely uses different browsers.

Additionally, agents are available for Windows and Linux, with the capability to connect to iOS and Android devices. The system also allows customization of channel parameters, such as bandwidth limitations, delays, and packet loss. Furthermore, it collects TCPdump data and screenshots at various load levels, which can be compiled into videos for analysis.

WebPageTest architecture

The WebPageTest architecture

The WebPageTest architecture features a web server that is primarily managed by a PHP application.

  • Agents, running on Windows or Linux, operate within complete virtual machines.
  • Mobile applications connect to these agents, with public cloud images available for added flexibility.

WebPageTest web interface

The WebPageTest web interface

The WebPageTest web interface uses a grading system, ranging from A to F, alongside text-based metrics.

The WebPageTest results

An important feature of WebPageTest is the charts. They show the loading speed for each page or application. 

At the top left is the time for HTML, then for CSS, Java Script, text, images, etc. After the seventh second, for example, you can see the overall load time of the page. 

At this stage, it is interesting to look at problems that prevented the page from loading faster. This is how the basic website performance optimization happens.

Comparative WebPagetest report

The WebPageTest report screenshot

The most important feature of WebPageTest is the screenshots. You can take two tests and compare their progress for each moment. At the bottom of the screenshot, you can see what percentage of the page content has been loaded.

Test result Data Plots

The WebPageTest report

If you are interested in pure analytics, you can take two pre-made tests and compare them. You will see the metric values for each test, the calculated confidence interval and difference in means, and an indication of whether the event was significant. In our example, the event was significant.

WebPageTest WPT can be automated with API. We recommend using the personal version, as you will have to wait a long time for the public version. For automation, you need to do the following:

  • Start the server and at least one agent. 
  • Send requests via REST API. 
  • Get the results in JSON, XML, or CSV or return to the web interface and retrieve the reports. 
  • Integrate WebPageTest with the process of Continuous Integration (CI). 
To stress test your site, you can use PFLB’s website load testing tool. It’s easy to use and helps you identify and fix bottlenecks with AI-powered performance insights.

Ready to Get Started with Website Load Test?

Lighthouse

Lighthouse provides comprehensive audit and all valuable data to use in website speed optimization. Here are its core features:

  1. 1.
    Performance audits: Evaluates loading speed metrics like First Contentful Paint (FCP), Speed Index, and Largest Contentful Paint (LCP).
  2. 2.
    Accessibility checks: Identifies issues for users with disabilities, such as missing alt text or low contrast.
  3. 3.
    Best practices: Ensures adherence to modern web standards and security protocols.
  4. 4.
    SEO audits: Reviews mobile-friendliness, meta tags, and other factors affecting search rankings.
  5. 5.
    PWA support: Assesses readiness for Progressive Web Apps, including offline functionality.

Lighthouse interface

The Lighthouse interface

The service interface is a tab within Chrome DevTools. There are also mobile and desktop versions. We recommend paying attention to the following modes in the interface: Performance and Best Practices.

If you want to start Lighthouse locally, you should push the F12 button in the Chrome browser, then choose Lighthouse in the panel and push the Report button.

Local start of Lighthouse

In Lighthouse, there are fewer network limitation options than in WebPageTest. In the latter, there are various limitations, from 2G to a wired connection, while in the former, there are only three types of limitations. Also, Lighthouse slows down the downloading processes to imitate a real mobile device.

Lighthouse test results

Load test by Lighthouse

In the report, you can see quality marks at the top. They are almost the same as the marks on the top right of WebPageTest.

  • Performance is the marker of the overall metrics used in the report. 
  • Best practices reflect how well we used site performance optimization. 

That being said, a checklist in Lighthouse comes with the service. When we use it we get a lot of data. But the real metrics are much more important. Lighthouse also provides screenshots, but they are relatively impractical because they do not show the speed index.

The Lighthouse architecture

The Lighthouse architecture looks like this: at the bottom, there is a Chrome tab that is connected to the Lighthouse module via the DevTools protocol. The Lighthouse collects the results of three test runs, calculates the metrics from them, and generates the report. The report can be in HTML or other formats.

Lighthouse CLI works in the command line as follows:

  • Install CLI via npm install. 
  • Run (example.com). 
  • You will get a JSON and HTML report. 
  • The service can also be integrated into various automation systems.

Speed Metrics

It’s important to know which metrics to pay attention to for each device. It pays to look at multiple metrics rather than picking just one. In particular, we recommend taking a look at the following parameters:

01 Load time

  • Load event: When the object is loaded or action is taken – such as HTTP request, picture download etc.
  • Full load time: When the entire page has loaded, including the relevant resources. 

02 Rendering start time

This is a critically important parameter. A user only pays attention to the moment when the white screen changes to something new while a page is loading. Even if it just changes color, the user sees that the system has reacted and something is happening inside it. That is why some resources use handy spinner icons that rotate while the page loads.

03 Time to first byte

This metric collects all the server performance information. If there are problems on the back end, it’s not as important to run front-end wordpress site speed optimization at the beginning. It’s worth paying attention to the server because it will take longer to respond and to fix the issues.

With the growth of wordpress website performance tuning, new metrics have evolved.
They aim to find a solution to the problem when a metric is not showing the true picture.

04 Speed index (Lighthouse, WebPageTest)

This is an important parameter that shows not only the page loading speed but also how fast the content of a page is visibly populated.

05 First contentful paint (LH)

Measured by Lighthouse, this marks the time when the first text or image is painted.

06 First meaningful paint (LH)

This is the time when the primary content of a page becomes visible, such as a product description or text in a header.

07 Input latency (LH)

Measured by Lighthouse, this is the time between a click and the response of the interface. It is often very long because CSS selectors perform many calculations.

08 Time to interactive (LH)

This is the time that it takes for the page to become fully interactive. When a user clicks, all the buttons are working.

The speed index metric can be displayed as a graph with time and percentage of visibility as axes.

Speed index chart

The speed index metric

The first example is the red test B, which loaded 18% of the content and stayed at that level until the 11th second, when it started loading the rest of the content. This is an example of a page that takes a long time to load but is fully displayed afterward. The second example is the blue test A, where 92% of the content loaded and the rest followed after the 11th second.

Speed index metric

The speed index metric 1

The speed index metric 2

In this case, the pages took the same time to load, but their behavior was completely different. Due to this, a formula that integrates the area above the graph up to 100% is perfect. It is the speed index. The smaller it is, the better.

For our testing service PFLB Platform, we have created many professional metrics that are easy to understand and useful to optimize your website.

How to Speed Up a WordPress Website Front-End Loading?

Optimizing your WordPress website’s front-end loading time is essential for improving user experience, boosting SEO rankings, and increasing conversions. Below, we’ve outlined actionable steps, explained their importance, and recommended tools to help you speed up your site.

01 Configure the server

Proper server configuration ensures smooth and efficient delivery of website content.

  • Transport Layer Security (TLS) Optimization: Enhances secure data transfer between your site and visitors, reducing latency.
  • Compression: Techniques like gzip, zopfli, and brotli minimize the size of files transferred, speeding up load times.
  • HTTP/2: Enables faster and more efficient data transfer by allowing multiple requests to be processed simultaneously.
  • Client Caching: Stores static resources (like images or scripts) in the browser, reducing the need to reload them on repeat visits.
  • TCP/IP Optimization: Improves network speed by reducing round-trip times and latency.

02 Optimize text resources (CSS, JS, HTML)

Poorly optimized code can slow down your website. Minify your CSS, JavaScript, and HTML files to improve WordPress website speed and ensure faster page rendering.

  • Minification: Removes unnecessary characters, spaces, and comments from your code. Tools like Minify Code can help.
  • Compression: Techniques such as gzip or brotli reduce file sizes for quicker downloads.
  • Connection Order: Rearranges resource loading for better rendering efficiency. For instance, prioritizing critical CSS helps the page display faster.
  • Collection: Consolidating multiple CSS and JavaScript files reduces the number of HTTP requests.

03 Use text instruments

Text compression ensures files are lightweight and delivered quickly.

  • Zopfli: Compresses files with minimal performance impact.
  • Brotli: Provides even better compression ratios than gzip.
  • Nginx Brotli Module: Integrates Brotli with Nginx for optimal server performance.

04 Optimize images

Large, unoptimized images can significantly slow down your site. HubSpot highlights the importance of compressing images and using appropriate formats.

  • Choose Suitable Formats: Use modern formats like WebP for better compression without losing quality.
  • Change Image Resolution: Resize images to the dimensions needed for your site.
  • Clean Metadata: Strip unnecessary metadata from images to reduce file size.

05 Use web fonts

Fonts can impact loading times if not optimized.

  • Use Modern Formats: WOFF2 offers better compression and performance.
  • Preload Key Fonts: Ensures critical fonts are loaded early in the rendering process.
  • Font Display Settings: Control how fonts are displayed while loading (e.g., “swap” for better user experience).
  • Tool: Font Squirrel provides web-friendly font formats.

06 Shorten JS blocks

Large JavaScript bundles can delay rendering.

  • Asynchronous JS: Allows non-blocking loading of JavaScript, improving load times.
  • Deferred JS: Delays loading of non-essential JavaScript until after the page loads.
  • Bundle Splitting: Breaks large scripts into smaller chunks for faster delivery.

07 Avoid a front-end single point of failure (SPOF)

A single resource failure shouldn’t block the entire page from loading.

  • Blocking CSS: Minimize critical CSS and load the rest asynchronously.
  • Blocking JS: Prioritize important scripts and defer non-critical ones.

08 Use Faster Plugins

WordPress plugins can be a double-edged sword. Choose plugins that are lightweight and well-optimized. For example:

  • Use WP Rocket for caching.
  • Avoid plugins with overlapping functionalities to reduce overhead.

09 Optimize WordPress Database

Over time, your WordPress database accumulates unnecessary data, slowing down queries. Use tools like WP-Optimize to:

  • Remove old revisions, spam comments, and transients.
  • Optimize database tables for faster queries.

10 Choose a Fast, Lightweight Theme

Themes with excessive features or heavy code can slow your site. Select a theme designed for performance, such as:

  • Astra
  • GeneratePress

These themes are lightweight, fast, and built with SEO in mind.

11 Use a Content Delivery Network (CDN)

A CDN distributes your website content across multiple servers worldwide, ensuring faster delivery to users, regardless of location. Popular options include:

  • Cloudflare
  • StackPath

12 Reduce Redirects

Redirects are often necessary for guiding users to updated pages or handling moved content, but excessive or poorly managed redirects can significantly slow down your website. Every redirect adds an extra HTTP request and response cycle, increasing load times and frustrating visitors.

To improve performance, audit your site for unnecessary redirects, such as redirect chains (when one redirect leads to another) or loops (redirects that send users in a circle). These not only slow down page loading but can also confuse search engines and harm SEO.

Consider PFLB Your Best Performance Testing Provider

When it comes to performance testing, PFLB stands out as a trusted partner with years of expertise in delivering reliable, tailored solutions. Whether you’re optimizing a WordPress website or scaling enterprise applications, our team ensures your digital systems meet the highest performance standards.

Why Choose PFLB?

PFLB specializes in performance testing, offering unique strengths that set us apart:

  • Unmatched expertise: With a deep understanding of diverse industries, we tailor our approach to meet your specific needs.
  • Cutting-edge Tools: From load testing to advanced analytics, we utilize state-of-the-art solutions powered by AI-driven insights.
  • Client-centric approach: We work closely with our clients to address their challenges, ensuring measurable, impactful results.
Explore Our Portfolio

Check out our portfolio and case studies for more insights into the challenges we’ve solved and the results we’ve delivered.

Visit our PFLB Case Studies Page to learn more.

Need Help with Load Testing?

Conclusion

Your website’s load speed is a vital asset for business success, directly impacting user satisfaction and conversions. Many websites fall short on performance, but by optimizing your WordPress site, you can gain a competitive edge.

Focus on the key areas covered in this article:

  • Metrics to monitor performance.
  • Testing Tools like Lighthouse and WebPageTest.
  • Optimization Tools for images, caching, and compression.
  • Modern Technologies such as HTTP/2 and CDNs.

Performance testing is essential, especially during high-traffic events like sales. For more tips and real-world examples, read our article “How to Speed Up a WordPress Site Part 2.” Optimize now to ensure a faster, seamless experience for your customers.

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