DEV Community: Stefan Gabos

Why Your Site Scores 90 on Desktop but 40 on Mobile (And How to Fix It)

Stefan Gabos — Sun, 31 May 2026 11:33:39 +0000

Run your website through Google PageSpeed Insights and you'll likely see two very different numbers: a comfortable green score on desktop, and a red or orange one on mobile. A site that scores 92 on desktop can score 38 on mobile.

That gap isn't a glitch — it's the whole point of the test. And the mobile number is the one that matters, because 64% of global web traffic is now mobile as of mid-2025. For a local business, the phone is where most "near me" searches begin.

Here's exactly why the mobile score is so much lower, what's dragging it down, and what actually fixes it. Every figure is sourced.

Why Mobile Scores Are So Much Lower Than Desktop

Lighthouse — the engine behind PageSpeed Insights — runs two completely different tests. The desktop test assumes a fast wired connection and a capable computer. The mobile test deliberately simulates a cheap, slow phone on a weak network. Two factors do the damage:

Throttled network. The mobile test simulates "Slow 4G" — roughly 1.6 Mbps download and 150 ms of latency — while desktop runs on a fast wired connection. (Lighthouse Throttling docs)

Throttled CPU. The standard mobile test applies a CPU slowdown to mimic a mid-tier phone, where desktop applies none. A mid-range Android chip is dramatically slower at parsing and running JavaScript than a laptop. (CPU Throttling in Lighthouse, DebugBear)

The effect on the metric that punishes heavy JavaScript is enormous. Across the whole web, the median desktop page has a Total Blocking Time of 67 ms; the median mobile page is 1,209 ms — roughly 18× more blocked. (Web Almanac 2024, HTTP Archive)

So mobile isn't scoring lower because the test is unfair. It's scoring lower because it's the honest test — it measures your site on the device most of your visitors are holding. The desktop score is the flattering one you can safely ignore.

Why Builder-Built Sites Score Worst of All

If your site was built on Wix, Squarespace, or a WordPress page-builder theme, the throttled mobile test hits especially hard, because those platforms ship a lot of code to every visitor. DebugBear's October 2025 comparison ran real Lighthouse tests across the major platforms. The mobile scores:

Builder	Mobile Score	Mobile LCP
Webflow	77	4.95 s
Wix	72	5.24 s
GoDaddy	63	3.93 s
WordPress.com	34	5.54 s
Squarespace	31	8.79 s

Squarespace's median mobile LCP of 8.79 seconds means the average phone visitor waits almost nine seconds for the main content to appear. Google's "good" threshold for LCP is 2.5 seconds. Even Wix, the strongest of the mainstream builders at 72, has a mobile LCP of 5.24 seconds — more than double the good mark.

Real-user data tells the same story. Across all sites measured by Google's Chrome User Experience Report, only 57% of Wix sites and 60% of Squarespace sites passed all three Core Web Vitals on mobile in 2024, and WordPress sat at 40% — versus a global average of about 51%. To the platforms' credit, every one of those numbers is trending up year over year. But "improving" and "fast" aren't the same thing, and a throttled phone test doesn't grade on a curve.

The short version: a drag-and-drop editor has to ship a general-purpose rendering engine to every visitor's phone, whether your page uses it or not.

What's Actually Dragging Your Mobile Score Down

Four things account for most of the damage. None of them are exotic — they're the default state of the modern web.

1. Too much JavaScript

JavaScript is the single biggest mobile killer because the phone has to download it, parse it, and run it — all on that throttled CPU. The median mobile page now ships 558 KB of JavaScript, and 44% of it goes completely unused. The median mobile page runs 14 "long tasks" that freeze the main thread for a combined 2,366 ms. (Web Almanac 2024 JavaScript Chapter)

2. Render-blocking resources

When a script or stylesheet in the page's <head> has to load before the browser can paint anything, the visitor stares at a blank screen. It shows up in the real-user numbers: only 51% of mobile pages hit a "good" First Contentful Paint, versus 68% on desktop. (Web Almanac 2024 Performance Chapter)

3. Heavy, unoptimized images

The median mobile page weighs 2.3 MB, up 357% over the last decade, and images are the largest slice. A hero photo exported straight from a phone or a stock library at full resolution is often the single element Lighthouse flags as your LCP — the thing the visitor is waiting for. (Web Almanac 2024 Page Weight Chapter)

4. Third-party scripts

Live chat widgets, booking embeds, analytics, review badges, font loaders, ad pixels — each adds code you don't control. Over 90% of pages load at least one third-party resource, and at the heavy end third-party JavaScript alone runs to 1,292 KB. (Web Almanac 2024 JavaScript Chapter) On a builder site you often can't remove these even if you wanted to.

Why a Bad Mobile Score Costs You Real Customers

A low PageSpeed number isn't a vanity metric. On mobile, speed maps directly to whether a potential customer stays or bounces — and for a local business, that visitor was often about to call or walk in.

Slow pages get abandoned. Google's widely cited 2016 study found 53% of mobile visits are abandoned if a page takes longer than 3 seconds to load. (It's an old figure and networks are faster now, but the direction hasn't changed.)
Every second cuts conversions. Portent's 2022 analysis found a page that loads in 1 second converts at 3.05%, versus 1.12% at 3 seconds — a 1-second site converts about 2.5× better than a 5-second one.
Even tiny gains matter. The Google-commissioned Deloitte study "Milliseconds Make Millions" found a 0.1-second mobile speed improvement lifted retail conversions 8.4% and lead-gen form submissions 21.6%.

For a local business this is sharper than for an online store, because local mobile searches are high-intent. Google's data has long held that 76% of people who search for something nearby on a smartphone visit a related business within a day. If your site takes nine seconds to paint on their phone, a chunk of that ready-to-buy traffic is gone before they ever see your hours or your phone number.

Mobile PageSpeed Is Also a Ranking Factor

Speed doesn't only lose the visitors who arrive — it can reduce how many arrive in the first place. Two things make the mobile score a search-ranking concern, not just a UX one:

Mobile-first indexing. Google has moved to mobile-first indexing for the web — it crawls and ranks the mobile version of your site, not the desktop one. The mobile version is the version Google sees.
Core Web Vitals feed ranking. Google says Core Web Vitals "aligns with what our core ranking systems seek to reward" as part of the page-experience signal — a tiebreaker between pages of comparable quality.

For a local business competing for "[service] near me," where several competitors offer similar content, a faster mobile site is exactly the kind of tiebreaker that decides who shows up first.

What Actually Fixes a Low Mobile Score

The fixes fall into two buckets: things you can do on your existing site, and the structural fix.

On your existing site

Compress and resize every image. Serve images at the size they actually display, in a modern format like WebP. This alone often moves the needle most, because images are usually the LCP element.
Defer or remove non-critical JavaScript. Add defer to scripts that don't need to run before paint, and delete the ones you don't use. Remember: 44% of mobile JS goes unused.
Audit your third-party scripts. Every chat widget, pixel, and embed has a cost. Keep the ones that earn their weight; cut the rest.
Self-host fonts and limit weights. Loading fonts from a third party adds a render-blocking round trip; self-hosting two weights instead of six is faster.
Test on mobile, not desktop. Always read the mobile tab in PageSpeed Insights. The desktop score is the one lying to you.

The structural fix

There's a ceiling to what you can tune on a builder site, because the platform's own overhead is baked in — you can optimize your images and still be shipping a rendering engine you never use. The structural fix is to serve the visitor's phone exactly what the page needs and nothing more.

That's what a hand-coded static one-page site does. No general-purpose editor runtime, no plugin stack, no unused JavaScript — just the HTML, the minimal CSS, and the images for your page. It's why a static site can score in the high 90s on the same throttled mobile test that leaves the mainstream builders anywhere from the low 30s (Squarespace) to the low 70s (Wix).

The Short Version

Mobile scores lower than desktop on purpose — the test simulates a slow, throttled phone, which is what 60% of your visitors use.
Builder sites score worst because they ship code to every phone: Squarespace's median mobile LCP is 8.79 s, Wix's 5.24 s, against a 2.5 s "good" mark.
The usual culprits are excess JavaScript, render-blocking resources, heavy images, and third-party scripts.
It costs customers (53% bounce past 3 seconds) and rankings (mobile-first indexing + Core Web Vitals).
Tuning helps; a hand-coded static site removes the ceiling entirely.

How to Check Your Own Score

Go to pagespeed.web.dev
Paste your website URL
Select the Mobile tab — that's the one that matters for rankings
Click "Analyze"

If you're on Wix, Squarespace, or WordPress and the mobile score is below 75, there's a hard ceiling on what you can fix from inside the dashboard. You can compress images and cut widgets, but the editor infrastructure and heavy frameworks load for every visitor no matter what you change.

Stefan Gabos is a senior web developer with 15+ years of experience building fast, accessible websites. He runs PageDrop — affordable one-page websites for small businesses, built with clean code and no monthly fees.

Why Wix, Squarespace, and WordPress Score Low on Google PageSpeed

Stefan Gabos — Sat, 21 Mar 2026 18:38:50 +0000

If you have ever run your website through Google PageSpeed Insights and watched the score land in the orange or red, you probably felt a mix of confusion and mild dread. Words like "Largest Contentful Paint" and "Total Blocking Time" appear, and suddenly you are staring at a wall of technical jargon that was never part of your plan when you signed up for a website builder.

According to DebugBear's 2025 study of real Lighthouse data, the average mobile PageSpeed scores for the most popular website builders are: Wix at 72, WordPress at 34, and Squarespace at 31. These are not outliers — they are the averages across thousands of live sites.

Here is the plain-English version of what that PageSpeed score means, why website builders consistently score this low, and why it genuinely affects your business — not just your anxiety about website metrics.

What Google PageSpeed Actually Measures

PageSpeed Insights is a free tool from Google that analyzes how fast and smooth your website feels to a real visitor. It does not just measure raw load time. It measures the experience — how quickly something useful appears on screen, whether the page shifts around while loading, and how long before a visitor can actually click a button without the page ignoring them.

The score is built from a group of measurements Google calls Core Web Vitals. The three that matter most are:

Largest Contentful Paint (LCP)

How long it takes for the main content — usually your hero image or headline — to appear on screen. Google wants this under 2.5 seconds. On a typical Wix site, LCP often lands between 3 and 6 seconds on mobile.

Cumulative Layout Shift (CLS)

Whether elements jump around as the page loads. Ever tried to tap a button on your phone and it moved just as you tapped it? That is a high CLS score. Website builders are particularly prone to this because of all the asynchronous scripts loading in.

Interaction to Next Paint (INP)

How quickly the page responds when someone clicks or taps something. Heavy JavaScript frameworks — the kind Wix and Squarespace rely on — often block the main thread, making the page feel sluggish even after it looks loaded.

A score of 95–100 means all three are in excellent shape. A score in the 30s or 40s — where Squarespace and WordPress typically land — means at least some of them are failing, often badly.

Why This Score Affects Your Google Rankings

This is where it stops being abstract. Since 2021, Google has officially included Core Web Vitals as a ranking factor. That means two websites competing for the same local search term — say, "dentist in Austin" or "coffee shop near downtown Raleigh" — will not rank equally if one loads fast and one does not.

Google's reasoning is straightforward: they want to send their users to pages that provide a good experience. A slow, janky site frustrates users, and Google tracks that behavior through Chrome field data. If visitors land on your page and leave quickly, those poor engagement signals reflect badly on your page — even if your content is excellent.

The practical consequence is real. A one-point improvement in your PageSpeed score is not going to transform your rankings overnight. But scoring 31 (Squarespace) or 34 (WordPress) versus 95–100 is a meaningful structural disadvantage in competitive local search, compounded over months and years.

Why Wix, Squarespace, and WordPress Sites Score Low

This is not a criticism of these platforms as products. Wix, Squarespace, and WordPress are genuinely useful tools that let non-developers put a professional-looking site online without hiring anyone. But the architecture that makes them easy to use is the same architecture that makes them slow.

They run on heavy JavaScript frameworks. When a visitor loads a Wix or Squarespace page, their browser does not just download your content. It downloads an entire application platform — the editor engine, the rendering layer, all the infrastructure that makes drag-and-drop editing possible. Your visitor never uses that editor. They are just reading your hours of operation and looking for your phone number. But their device still has to process all of it before your page becomes usable. WordPress has a different problem: themes and plugins pile up JavaScript and CSS that the page does not need, and the database-driven architecture adds server-side latency.

They load third-party scripts you did not ask for. Analytics, advertising pixels, live chat widgets, cookie consent tools, font loaders — every integration adds a request, and every request adds time. All three platforms include several of these by default. Some you opted into, some you did not. Each one has to complete before the browser can finish rendering your page.

Images are often not optimized at the source. Website builders will compress images to a degree, but they serve them in ways that are not always efficient for every device. A visitor on a mobile phone with a mid-range connection is often downloading imagery sized for a 1440-pixel desktop monitor.

The server response itself carries overhead. Wix and Squarespace use dynamic server-side rendering, which means every page visit triggers a process on their servers to assemble your page before sending it. WordPress queries a database on every request unless you add caching plugins. This adds latency before a single byte reaches your visitor's browser.

None of this is fixable from within the platform's interface. It is baked into the architecture.

What a Low PageSpeed Score Actually Costs You

Beyond rankings, there is a direct conversion cost to slow websites that independent research has documented consistently.

Research from Google and SOASTA found that as mobile page load time increases from one second to three seconds, the probability of a visitor bouncing increases by 32 percent. At five seconds, that probability jumps to 90 percent. Separately, in a case study cited by Google on web.dev, the BBC reported losing an additional 10% of users for every extra second their site took to load.

For a local business website, the math is simple. If someone searches for your service, finds your site, and leaves before it finishes loading — they go to your competitor. They do not wait. They do not come back. That is a customer you paid for with your time, your Google Business Profile effort, your word-of-mouth reputation, or your ad spend, and they left before they even read your first sentence.

A mobile visitor searching "emergency plumber near me" at 9pm is not going to wait four seconds for your homepage to finish loading its JavaScript bundle. They are going to tap the next result.

What 95–100 Looks Like in Practice

Sites that score in the 95–100 range are built differently from the ground up. They serve clean, minimal HTML and CSS with no platform overhead. Images are properly sized, compressed, and served in modern formats. There are no unnecessary third-party scripts running before the page is usable. The server delivers a complete, pre-built page instantly, with nothing to assemble at request time.

This is how hand-coded static sites work by design. Every site is a self-contained HTML file — no WordPress, no Wix, no framework. Just clean code that browsers can render immediately.

That is not a feature bolted on after the fact. It is a consequence of how the sites are built.

The Honest Bottom Line

A low PageSpeed score is not a catastrophe, and fixing it will not instantly triple your leads. But scoring 31 or 72 when your competitor scores 95 is a real, measurable disadvantage in search — and it represents a portion of potential customers who are leaving your site before they can become actual customers.

If you are investing in local SEO, running Google Ads, or asking customers to find your local business website online, the performance of that site is part of the investment working or not working. A slow site leaks value from every other effort you make to get found.

The good news is that this is a solvable problem. It does not require a complicated technical overhaul or an ongoing monthly subscription. It requires a site built correctly in the first place.

How to Check Your Own Score

It takes 30 seconds:

Go to pagespeed.web.dev
Paste your website URL
Make sure "Mobile" is selected (Google uses mobile-first indexing, so this is the score that matters for your rankings)
Click "Analyze" and wait for the results

Look at the number in the circle at the top. Green (90–100) means you are in good shape. Orange (50–89) means there is room for improvement. Red (0–49) means your site is actively hurting your search performance and losing visitors.

If you are on Wix, Squarespace, or WordPress and the score is below 75, there is not much you can do within the platform to fix it. You can reduce the number of apps and plugins, compress images before uploading, and remove unnecessary widgets — but the core performance ceiling is set by the platform itself. The editor infrastructure and heavy frameworks load for every single visitor regardless of what you change in your dashboard.