The Speed and Mobile Checklist

The checklist

Run every one of these on a phone, on cellular data, not on your office wifi.

• Loads in under 2.5 seconds on a phone, tested on real 4G
• No layout jump as it loads, nothing moves under your thumb
• Images sized and compressed for mobile, not desktop files scaled down
• Green, not red, on Google PageSpeed Insights, mobile tab
• Main button in thumb reach, tappable without zooming
• No popup covering the content on landing
• Phone number or booking button visible without scrolling
• Still works on a weak signal, one or two bars

How to test in two minutes

One. Go to pagespeed.web.dev, paste your URL, switch to the Mobile tab, and look at the coloured bars at the top. Those are your real-visitor numbers if Google has enough data for your site. Below them is a lab test with a list of what to fix.

Two. Load your own site on your own phone, on cellular, and count out loud. "One thousand and one, one thousand and two." If you get past three, you have a problem worth money.

The second test matters more than the first. A score is an opinion about your site. Watching your own homepage crawl while you count is a fact about your customer's experience.

Fix in this order

Most speed advice is a list of thirty things, which is why nobody does any of them. There is an order, and it is not the order the tools give you.

First, images. On almost every site we audit, images are most of the page weight and the single biggest win. Three things: export at the size they actually display rather than shrinking a 4000px photo in the browser, save as WebP rather than PNG or JPEG, and set width and height on every image so the browser reserves the space.

That last one is also most of your layout-jump problem, so you fix two metrics with one change.

Second, what loads before anything is visible. Fonts, chat widgets, tracking scripts, review widgets, popup tools. Each one is a request that happens before your customer sees anything. Audit what is actually on the page. Most sites are carrying two or three tools nobody has used in a year.

Third, everything else. Caching, minification, the clever server things. Real, but worth far less than the first two, and usually your host's job rather than yours.

Do not start with the clever things. We have seen sites with a beautifully tuned cache serving 6MB of unoptimised hero images.

Reading the diagnosis, not just the score

PageSpeed gives you a number. The number tells you there is a problem, not what it is. Google's own breakdown of Largest Contentful Paint splits the load into stages, and which stage is slow tells you who has to fix it.

Time to first byte. From the moment someone taps the link to the moment the first bytes of your page arrive. If this alone is over a second, nothing you do to the page will save you. Google names the usual causes: chains of server redirects, visitors far from the nearest server, and pages that cannot be cached because of query parameters. This is a hosting and configuration problem, not a design one.

First byte to first paint. A big gap here means the browser is downloading a pile of render-blocking assets before it can show anything, or the page is being assembled in JavaScript rather than delivered as HTML. That is a build problem. It is also the single most common thing we find on sites built with heavy page builders.

First paint to largest paint. A big gap here means your main image or headline is not available early enough, usually because it is loaded by JavaScript instead of sitting in the initial HTML. This one you can often fix yourself, by making sure the hero image is a plain image tag in the markup.

Knowing which of the three is slow turns "the site is slow" into a specific job for a specific person.

The mobile checks people skip

Speed is only half of it. A fast site you cannot use on a phone still loses.

Thumb reach. Hold your phone one-handed, the way a customer waiting somewhere would. Can you reach the main button with your thumb without shifting your grip? Buttons in the top corners fail this.

The popup on landing. A popup that covers the content before someone has read anything is the fastest way to lose a first-time visitor, and Google treats intrusive interstitials on mobile as a ranking problem. If you must have one, trigger it on exit or after real engagement, never on arrival.

The phone number. For a local service business this is the whole point. It should be visible without scrolling and it should be a tappable link, not text someone has to copy.

The weak signal test. Turn wifi off, find a bad spot, and load your own site. This is what a customer standing outside your competitor's shop is experiencing.

What to do with the results

Write down your three Core Web Vitals numbers today, before you change anything. Then fix images, and measure again a week later. A week matters because the real-visitor data updates on a rolling 28-day window, so a fix does not show up immediately even though it is already helping people.

If you cannot get under 2.5 seconds after the images are handled, the problem is usually the theme or the page builder rather than anything you can configure. That is a rebuild conversation, not a plugin conversation.