Before learning how to speed up WordPress, it’s important to know how to measure website speed so that you can benchmark and gauge improvements when you do start doing speed optimisation.
Measuring WordPress website speed can be done with several tools, each offering unique insights into performance. Here’s an overview of some popular tools for speed testing.
Here are some popular speed testing tools that I’ve used over the years including my thoughts on each.
1. Google PageSpeed Insights
This free speed test tool analyzes website speed on both mobile and desktop, providing scores and recommendations based on best practices and performance optimization. It shows important speed results from real users and a simulated test. This is what I used in the above screenshots.
My favourite thing about Google PageSpeed Insights is that it provides real user data if Chrome has collected enough data from website visitors over the last 28 days. If your website gets enough traffic from people using Chrome, you’ll get real user data at a page level, if not, then you’ll see data at the website level, i.e. taking into account all pages.
It’s important to note that the real user data is collected from visitors using a wide range of devices and internet connections. As you can imagine, your website won’t load as fast using 3G, or 4G, compared to a fast broadband internet connection. So, the real user data being reported is somewhat limited because it encompasses all visitors. However, Google PageSpeed Insights does tell you what percentage of visitors fall within each of their test categories (Good, Needs Improvement, and Poor) for each core web vital. In addition to this, they give you the result of the 75th percentile for the core web vital being measured, which means 75% of visitors are experiencing that stated result or better.
For example, over the last 28 days, 75% of visitors to huskygifts.com have experienced a Largest Contentful Paint Time of 1.7s, with 87% experiencing less than 2.5s (considered Good), 8% experiencing 2.5s to 4s (considered Needs Improvement), and 5% experiencing more than 4s (considered poor). As mentioned, this range of results is mostly caused by different visitors using different devices and different internet connections.
The above is especially true for websites that get a significant amount of visitors from countries with a relatively slow internet connection compared to Australia. e.g. Philippines, India, Malaysia, Nepal, Pakistan, South Africa, Sri Lanka, and Nigeria.
If your website doesn’t have enough traffic, don’t worry, Google PageSpeed Insights also shows a simulated test of mobile and desktop using Google Lighthouse. More on this below.
2. Google Lighthouse
Integrated into Chrome DevTools, Lighthouse is a free speed test tool that offers comprehensive audits on performance, accessibility, SEO, and best practices, providing actionable suggestions to enhance website speed.
Google Lighthouse is an open-source, automated tool developed by Google for improving the quality and performance of web pages. It’s integrated into the Chrome DevTools and available as a standalone tool and a command-line interface. Lighthouse assesses web pages across several categories:
- Performance: Evaluates aspects like load times, resource sizes, and other metrics crucial for speedy page rendering.
- Accessibility: Checks for adherence to best practices and standards for web accessibility, highlighting areas for improvement.
- Best Practices: Examines whether the page follows recommended web development practices to ensure a robust and secure browsing experience.
- SEO (Search Engine Optimization): Assesses the page’s adherence to best practices for search engine optimization and suggests optimizations to improve discoverability.
- Progressive Web App (PWA): Determines if the web page meets the criteria for a Progressive Web App, which offers an app-like experience on the web.
Lighthouse generates a comprehensive report after analyzing a webpage, providing scores and detailed information about various performance aspects. It also offers suggestions and actionable recommendations to optimize the website for better performance, accessibility, and user experience.
Developers, designers, and website owners use Google Lighthouse to identify areas for improvement and optimize their websites according to industry best practices and standards, thereby enhancing user experience and overall performance.
As mentioned, Google PageSpeed Insights uses Google Lighthouse. In fact, most speed testing tools use it. However, the way they use it can differ, therefore test results can vary between different tools using Google Lighthouse.
3. GT Metrix
GT Metrix is a free speed test tool (with a premium option) that analyses your website performance by assessing Core Web Vitals with Google Lighthouse. GT Metrix also analyses your page structure to help identify better ways of delivering page assets like images, CSS, Javascript, etc.
Note that GT Metrix has Google Lighthouse configured slightly differently from using Google Lighthouse in Chrome Dev Tools.
Here are the advantages of using GT Metrix over Google PageSpeed Insights or Google Lighthouse in Chrome Dev Tools:
- GT Metrix loads pages using a real browser, not an emulated browser
- GT Metrix lets you test from different locations, and even more on the paid plan
- GT Metrix lets you choose between a wide range of simulated devices/browsers (paid plan)
- GT Metrix has the option to test using a real device – Galaxy Nexus (paid plan)
- GT Metrix lets you choose between different internet connection types
Note: GT Metrix has significantly limited their free version recently to less than 5 tests per month.
Try GT Metrix
4. Pingdom
Pingdom is a simple and free speed testing tool that provides basic recommendations about why your website might not be as fast as it could be. I say ‘might’ because some of the recommendations are outdated based on old server technology.
While Pingdom does provide some good insights, a couple of its recommendations are outdated based on websites that get served using the old HTTP/1.1 protocol. While some websites are still served using HTTP/1.1, you shouldn’t be using a hosting provider that only provides this. Your host should support both HTTP/2 and HTTP/3. Also, your host should support both Gzip and Brotl compression. Pingdom only tests for GZIP so you’ll score 0/100 if your hosting provider uses Brotl compression like mine does.
Another issue with Pingdom is that it sometimes shows inaccurate screenshots of your website, or is sometimes blank. I believe this is because they use Onload Time instead of Fully Loaded Time to mark the end of the speed test.
So, if you choose to use Pingdom, you can ignore the recommendation about ‘Compress components with gzip’ if your host uses the superior Brotl compression. Instead, use this tool to test Brotl compression. And you can ignore most of the recommendations under ‘Make fewer HTTP requests’. While it can help to reduce HTTP requests, they shouldn’t be reduced using outdated techniques like merging/concatenation, CSS sprites, etc.
Try Pingdom
5. WebPageTest
WebPageTest is one of the best free tools for testing website speed on a wide range of real devices. This platform offers a few different tests including Site Performance, Core Web Vitals, Lighthouse and Trace Route tests. The Site Performance test is the one you want to run.
One of the things that makes WebPageTest stand out from other platforms that allow real device testing is the many advanced settings to customise your test. You can find them all in Advanced Configuration. In fact, if you are going to use WebPageTest, I only recommend using the Advanced Configuration. This is what allows you to choose from different devices, locations, etc. The Simple Configuration seems like it’s primarily suited to running quick mobile and desktop tests from US-based servers on their default testing device. You also have a mobile test option for Mumbai and a desktop test option for Toronto and Frankfurt, but these aren’t that useful for me, especially when it only takes a minute to configure the advanced settings.
Overall I love WebPageTest because the Advanced Configuration allows you to test a wide range of real devices from many different locations around the world, along with many advanced settings. However, WebPageTest might feel overwhelming to some people because of all the advanced settings. If this sounds like you, I recommend trying BrowserStack Speed Lab instead. More on this below.
Try WebPageTest
6. BrowserStack SpeedLab
BrowserStack SpeedLab is a really good alternative to WebPageTest that also allows you to test real devices. It’s easier to use than WebPageTest, but it’s limited to four test areas including EU (west), US (west), US (east), and Australia. You also get slightly fewer test connection types, but you get the most important ones including 3G, 4G Slow, 4G, LTE, and unthrottled (essentially cable).
I believe the UI of BrowserStack SpeedLab is nicer than WebPageTest providing a better user experience. The speed test report and recommendations are included on the same page and are much easier to understand than WebPageTest.
BrowserStack SpeedLab is my favourite speed test tool.
7. Speed Vitals
Use this tool primarily for testing Time To First Byte (TTFB) around the world, if you have a global audience. The TTFB to a single location isn’t that important and is somewhat arbitrary because it will be very different for different devices and different internet connections. What is important is consistent low TTFB times to locations around the globe. e.g. ~100ms or less to all major cities when testing using Speed Vitals. If there are big differences or if all TTFB times are slow, e.g. greater than 200ms, then you need to use a better CDN.
If you don’t use a CDN, then you’ll see relatively slow TTFB times in almost all countries except where your server is located. In this case, I recommend using Cloudflare Enterprise (through Rocket.net) or Fastly CDN. Doing so should get your TTFB times down to ~100ms or less from all major cities when testing with Speed Vitals.
A good alternative to the Speed Vitals TTFB test is the Key CDN Performance Test, which does the same thing, but from fewer locations.
Try Speed Vitals
How to Measure Website Speed
Here are some steps you can follow to get a good measurement of WordPress website speed.
- Use Google PageSpeed Insights to check for real user data and/or simulated core web vital metrics.
- Use WebPageTest, Browser Stack’s SpeedLab, or the paid version of GT Metrix to run tests using a real device from their location, ideally, a device that your ideal customer or client is likely to use. This is the closest you’ll get to a controlled test with real user data.
- If you have a global audience, use the Speed Vitals TTFB test to see how quickly your server responds to visitors in different countries. This will help you figure out whether you need a Content Delivery Network (CDN), need to use a better CDN or need to fine-tune your current CDN provider.
- Investigate the recommendations given by each speed testing tool.
- Follow the tips below about how to speed up WordPress.
Final Thoughts
Those are all of the free website speed test tools that I personally use and recommend.
My favourite speed test tool is Browser Stack’s SpeedLab.
What website speed tools have you used?
Share your favourite and reasons why in the comments below.
