How to Measure Your Website Speed: PageSpeed and GTmetrix

Introduction

“My website is slow” is one of the most common complaints, but also one of the hardest to fix if you don’t know where the problem is. Is it the hosting? The images? A plugin? The theme?

To answer that you need to measure speed objectively, with tools that tell you exactly what slows your website down. In this article you’ll see how to use the two most important free tools —PageSpeed Insights and GTmetrix— and how to interpret what they tell you.

Why your website’s speed matters

Google has confirmed that speed is a ranking factor. Additionally:

• A slow website sells less. Amazon found that every 100ms of delay cost them 1% in sales.
• Users abandon. More than half of visitors leave if a website takes more than 3 seconds to load.
• Google penalizes you. Speed metrics have been part of Google’s algorithm since 2021.

At miHosting we use servers with NVMe SSD and LiteSpeed, which offer load times below 200ms. But speed also depends on how your website is optimized.

Tool 1: PageSpeed Insights (from Google)

PageSpeed Insights (PSI) is Google’s official tool. It’s the most important because it uses the same data Google uses to evaluate your website.

How to use it

1. Go to pagespeed.web.dev.
2. Type your website’s URL.
3. Select Mobile or Desktop.
4. Click Analyze.

[Imagen sugerida: screenshot of PageSpeed Insights analyzing a website]

What it shows you

PageSpeed gives you two types of analysis:

Field analysis (real user data)

Shows real data from the Chrome User Experience Report, that is, how real users experience your website on their devices. Here the Core Web Vitals appear:

• LCP (Largest Contentful Paint): time until the largest visible element loads.
• INP (Interaction to Next Paint): response time to the first interaction.
• CLS (Cumulative Layout Shift): visual stability (whether elements “jump” when loading).

Lab analysis (Lighthouse)

Simulates loading under controlled conditions and gives you:

• A score from 0 to 100 in performance.
• A list of opportunities and diagnostics: concrete things you can improve, with the estimated time savings.

The lab score can vary between tests, because it depends on the simulated device and network. What matters is the trend, not the exact number.

Tool 2: GTmetrix

GTmetrix is another free tool (with a paid version) that analyzes your website’s speed. It’s complementary to PageSpeed because it gives you different information.

How to use it

1. Go to gtmetrix.com.
2. Type your URL.
3. (Optional) Configure the country it’s tested from and the browser.
4. Click Analyze.

[Imagen sugerida: screenshot of GTmetrix showing a website report]

What it shows you

GTmetrix gives you:

• Performance scores (based on Lighthouse).
• Waterfall: a chart showing the order and duration of each resource your website loads. It’s very useful to see which specific element takes a long time.
• Key times:
  • Total load time.
  • Total page size.
  • Number of requests.

The GTmetrix waterfall is one of the most useful tools for detecting bottlenecks. If you see a very long bar, the problem is there.

Which metrics you should look at

Don’t obsess over the overall 0 to 100 score. Look at these specific metrics:

Metric	Goal	Tool
LCP (loading of main element)	< 2.5s	PageSpeed
INP (response to interaction)	< 200ms	PageSpeed
CLS (visual stability)	< 0.1	PageSpeed
Time to first byte (TTFB)	< 600ms	GTmetrix
Total load time	< 3s	GTmetrix
Page size	< 2 MB	GTmetrix
Number of requests	< 80	GTmetrix

If you meet the Core Web Vitals goals (LCP, INP, CLS), you’re on the right track for Google to consider your website fast.

How to interpret the recommendations

Both tools give you a list of things to improve. The most common:

Eliminate render-blocking resources

CSS and JavaScript files that stop the page from loading until downloaded. Solution: minify them, defer them, or remove the ones you don’t use.

Optimize images

Images are usually the heaviest element on a website. Solution: compress them, use modern formats (WebP) and size them correctly.

Enable text compression

Gzip or Brotli reduce the size of text files (HTML, CSS, JS). Usually active on good hosts.

Leverage browser caching

Tell the browser to save static files so it doesn’t download them again. Configured with HTTP headers.

Reduce server response time (TTFB)

Depends mainly on the hosting and server configuration. If your TTFB is high, your hosting may be the problem.

Common mistakes when measuring speed

The score changes every time I test

It’s normal. Lab analysis depends on network conditions and the server at that moment. Look at the trend, not a single test.

I score 100 on desktop but low on mobile

It’s very common. Mobile has less power and worse connection. Prioritize the mobile version, which is what Google uses to index.

My website loads fast on my computer but PageSpeed says it’s slow

Your computer may be more powerful or have a better connection than the average user. Trust the tools, not your perception.

I improved and the score doesn’t go up

It may be cache. Wait a bit (24 hours) or test on a URL with parameters to bypass the cache. It may also be that the improvement doesn’t affect the metrics measured.

Frequently asked questions

What score is good on PageSpeed?

A score of 90 or higher on mobile is excellent. Between 50 and 90 there’s room for improvement. Below 50 is a slow website that needs attention.

PageSpeed or GTmetrix?

Both. PageSpeed gives you Google’s view (the one that matters for SEO); GTmetrix gives you the waterfall to diagnose specific problems.

Why are field and lab data different?

Because they measure different things. Field data is real (real users); lab data is simulated (controlled conditions). Ideally they’d match, but not always.

Does my hosting affect speed?

A lot. Server response time (TTFB) depends mainly on hosting. A hosting with NVMe SSD and LiteSpeed has a much lower TTFB than basic hosting.

How often should I measure speed?

After any major change (installing a plugin, changing theme, adding images). And at least once a month, to detect degradations.

Measure before improving

You can’t improve what you can’t measure. Before touching anything to speed up your website, measure with PageSpeed Insights and GTmetrix to know exactly where the problem is. Then, order improvements by impact: images, cache and server are usually the ones users notice most.

If your website is slow because of hosting, at miHosting we offer plans with NVMe SSD, LiteSpeed and native caching that offer much lower load times than conventional hosting. Open a ticket from your client panel and we’ll help you measure and optimize your website.