What is PageSpeed and why it should be 100/100
PageSpeed is the score Google gives your website. Below 90 you lose customers and rankings. We explain what it measures, why it matters and how to reach a real 100/100.
Key points
When you show your website to a potential customer, the first thing they see is the design. When Google analyses it, the first thing it measures is the speed. And the score it gives has a specific name: PageSpeed.
PageSpeed is Google’s official scoring system for web performance. It runs from 0 to 100, measures mobile and desktop separately, and is free: you can test your website right now at pagespeed.web.dev. If your score is below 90, you have a problem. If it is below 50, you are losing customers every single day without realising it.
1. What PageSpeed actually measures
PageSpeed is not a single metric. It is the result of analysing your website against dozens of technical parameters and summarising them into a global score. The three most important are the Core Web Vitals, which Google turned into an official SEO factor in June 2021.
LCP (Largest Contentful Paint): how long it takes for the largest element on the page to appear, usually the main image or the title. The target is below 2.5 seconds. If it takes more than 4 seconds, the website is considered slow.
INP (Interaction to Next Paint): how long the page takes to respond when a user interacts with it (clicking, typing, scrolling). The target is below 200 milliseconds. If it takes more than 500 ms, the experience feels “sluggish and unstable”.
CLS (Cumulative Layout Shift): how much the elements on the page shift while loading. When you are about to click a button and it suddenly jumps because an image appeared late, that is CLS. The target is below 0.1.
Beyond Core Web Vitals, PageSpeed measures other factors: time to first byte, total page size, number of requests, JavaScript usage, image optimisation, custom fonts and caching.
2. Why Google penalises slow websites
Google has a very simple goal: serve results that users want to click and that load quickly. If it sends people to a website that takes 8 seconds to load, the user hits back and tries another result. That makes the search engine lose trust. To avoid it, Google ranks fast websites higher.
The data backs it up: according to a Google study, websites with a 1-second load time have a 9% bounce rate. With a 5-second load time, the bounce rate jumps to 38%. 53% of mobile users abandon a page if it takes more than 3 seconds to appear.
And it is not just about traffic. Speed has a direct impact on sales. Walmart calculated that every 100 milliseconds of improvement in load time increased sales by 1%. Amazon reached the same conclusion: 100 ms = 1% more sales.
At an SMB scale, the numbers are equally clear: a website with PageSpeed 50 loses between 20% and 40% of conversions compared to a site with PageSpeed 95. If you receive 1,000 monthly visits and a single deal is worth 500 EUR, losing 30% of conversions because of slowness adds up to tens of thousands of euros a year.
3. Why most websites do not reach 90
If you measure your business website right now at pagespeed.web.dev, it is likely that the mobile score is below 50. It is not your fault, it is a predictable consequence of how most websites have been built over the past 10 years.
Cause #1: WordPress with too many plugins. Each plugin adds JavaScript and CSS code to your site. 30 plugins can easily add 2 MB of code that loads every time someone opens a page. Heavy plugins like Elementor or WPBakery can add 5 MB on their own.
Cause #2: Unoptimised images. A photo taken with a phone weighs between 3 and 8 MB. If you upload it directly without optimising, every visitor has to download those megabytes. Multiply that by 10 images per page and you have a website that is practically unusable on mobile.
Cause #3: Third-party scripts. Google Analytics, Facebook Pixel, live chat, Google Maps embeds, embedded videos. Every third-party script adds delay. A website with 8 external scripts can take 2 seconds just to load them.
Cause #4: Cheap shared hosting. If you pay 5 EUR a month for hosting, you share the server with 200 other websites. When one of them gets a traffic spike, yours slows down. The server never responds quickly.
Cause #5: No caching, no CDN. Without caching, every visit forces the server to generate the page from scratch. Without a CDN, users in Mallorca or Madrid download your files from a server in Catalonia, adding milliseconds to every element.
4. What it takes to reach 100/100
Reaching 100/100 is not impossible: it is a matter of architecture. These are the 6 technical decisions that make it possible:
1. Pre-generated static pages. Instead of generating each page on the server every time someone requests it, you generate every page once when you publish. The server only sends pure HTML, with nothing to execute. Astro, the framework we use at serpixel, works exactly that way.
2. Images in WebP or AVIF format. WebP reduces image file size by 25% to 35% compared to JPG, with no visible quality loss. AVIF reduces it even more (up to 50%). Each image should have a mobile and a desktop version, with exact sizes.
3. Minimal JavaScript, only where needed. A homepage does not need JavaScript to load. The menu, the buttons, the forms: everything can work with pure HTML and CSS. JavaScript only needs to be added where there is real interactivity (a map, a chat).
4. Custom fonts with font-display: swap. If you use Google Fonts or custom typefaces, they should load in a non-blocking way. That means the text first renders with a system font and then swaps to your custom one once it has been downloaded, without blocking the load.
5. Global CDN. Vercel, Cloudflare and Netlify distribute your files across hundreds of servers around the world. When someone visits your site from Berlin, they download the files from the nearest server, not from a server in Catalonia.
6. Total removal of unnecessary third-party plugins. Every live chat, every testimonials widget, every heavy cookie banner drags the score down. There are lightweight alternatives for everything.
5. How to measure PageSpeed correctly
There are three places where you can measure your website’s performance. They are all free, but they will give you slightly different results.
pagespeed.web.dev is Google’s official tool. It measures mobile and desktop separately, shows the Core Web Vitals and gives you a list of issues with concrete suggestions. It is the most reliable option for an initial diagnosis.
Lighthouse is a tool built into the Chrome browser (right click > Inspect > Lighthouse). It lets you run audits from your own computer. Useful when you want to test changes locally before publishing.
GTmetrix is an alternative with more visual reports and historical tracking. Useful for monitoring how the website evolves over time.
Important: the mobile score is what matters. Google indexes the mobile version of your website first (mobile-first indexing) and there are more users browsing from mobile than from desktop. If your mobile score is 40 and your desktop score is 95, you have a serious problem.
6. What happens if you have a low score
Not everyone needs to score 100. But there are thresholds that signal risk:
| Mobile PageSpeed | Status | What happens |
|---|---|---|
| 90-100 | Excellent | Google rewards you, users do not bounce |
| 70-89 | Acceptable | No penalty, but you lose ground to faster competitors |
| 50-69 | Bad | You lose between 20% and 30% of mobile visits |
| 0-49 | Critical | Google actively penalises you. You lose rankings, you lose customers |
If your score is below 70, this is not a cosmetic issue: it is a business issue. Every month that passes, you lose traffic, you lose conversions and you lose rankings.
The serpixel commitment: 100/100 guaranteed
At serpixel we build every website with Astro, a framework designed from day one for speed. We generate static pages, automatically optimise every image to WebP, remove unnecessary JavaScript and use Vercel as a global CDN.
The result: every serpixel website maintains 100/100 PageSpeed on mobile and desktop from day one. It is not a coincidence, it is a direct consequence of the technology we use.
And we do not just hit 100/100 at launch. Every month, as part of the integrated maintenance, we measure each client’s score and act if it drops for any reason (a new image badly optimised, a script added by mistake). 100/100 is not a one-off state, it is an ongoing commitment.
Want to know your website’s current PageSpeed? Request a free audit and we will send you a report with the real score, the specific problems your site has and how to fix them.