Why your website needs to be fast: Google, PageSpeed and customers

Customers usually open your website on a phone, on the go, over mobile internet. If the page takes too long to load, they will not wait: they will go back and open a competitor’s site instead. Google knows this too and takes page experience, including speed, into account.

Below we explain in plain language why speed matters, how Google measures it and where to start.

Why speed matters

For customers. A fast site builds trust. A slow page, buttons that jump around and text that appears late are all reasons to leave.
For Google. Google considers page experience, including the Core Web Vitals metrics, in its ranking systems. Relevance to the search query still comes first, but among similar pages the one with the better experience can get an edge.
For advertising. If a visitor from a paid ad leaves before the page loads, that ad money is wasted.

Core Web Vitals in plain language

Core Web Vitals are three key metrics that Google has chosen to measure user experience.

LCP: when the main content appears

Largest Contentful Paint measures how long it takes for the largest element on the page, usually the main image or headline, to appear. A good result is 2.5 seconds or less.

INP: how quickly the site responds

Interaction to Next Paint shows how quickly the page responds when someone taps a button or opens a menu. A good result is 200 milliseconds or less. In March 2024, INP replaced the older FID metric.

CLS: does the page jump around

Cumulative Layout Shift measures how much elements move while the page loads. If you are reading text and an image suddenly appears above it, pushing everything down, that is poor CLS. A good result is 0.1 or less.

Google evaluates these metrics using data from real users: a page counts as good when it stays within the threshold for at least 75 percent of visits.

What PageSpeed Insights shows

PageSpeed Insights (pagespeed.web.dev) is a free tool from Google. It shows two kinds of data:

Real user data — statistics collected from Chrome users. If your site has few visits, this section may be empty.
A lab test (Lighthouse) — the page is checked under simulated conditions and scored from 0 to 100. A score of 90 or above is shown in green and considered good.

The mobile test deliberately simulates a slower network and a mid-range phone. That is why the mobile score is usually lower than the desktop one; focus on the mobile score.

The mobile internet factor

Mobile internet speed varies by location, time of day and carrier. A site tested on a computer over fast office Wi-Fi can behave very differently on a phone. Every extra megabyte means more waiting and more data used by your customer. That is why a website should be designed first for a phone and an ordinary mobile connection.

Google also indexes sites mainly by their mobile version (mobile-first indexing).

Image optimization

On many websites, images make up a large share of the page weight. They are a good place to start:

Modern formats. An image in WebP or AVIF is usually noticeably lighter than the same image in JPEG or PNG.
The right size. A phone screen does not need a 4000-pixel-wide photo; serve each screen a right-sized version (srcset).
Lazy loading. Let images further down the page load when the user scrolls to them. But do not lazy-load the main image on the first screen, as that hurts LCP.
Set dimensions. When an image has a width and height, the browser reserves space for it in advance, and the page does not jump (CLS).
Compression. A quality drop the eye cannot see noticeably reduces file size.

Other important factors

Excess JavaScript. Every library, widget and animation loads the phone’s processor; remove what you do not need.
Fonts. Load fonts from your own server and keep only the weights and character sets you actually use.
Third-party scripts. Chat widgets, piles of analytics tags and ad code noticeably slow a page down.
Server and caching. The server should respond quickly, and static files should be cached and served through a CDN.

How speed connects to SEO

Speed is not the only SEO factor: useful content, clear headings and trustworthy links still come first. But speed affects search performance in several ways:

Core Web Vitals are part of the page experience signals;
a fast page keeps visitors on the site instead of sending them back to the search results;
when the server responds quickly, Google can crawl more of your pages and notice new ones sooner.

How to check your site

Test your site at pagespeed.web.dev and look at the mobile result.
Open the Core Web Vitals report in Google Search Console to see which pages have problems.
Start with the heaviest images: format, size, compression.
Remove unnecessary plugins, widgets and scripts.
Try the site on a real phone over mobile internet.

About this website

The uflex.uz website itself was built on these same principles, with a PageSpeed score of 100 as the goal: no heavy JavaScript framework on public pages, fonts served from our own server, and optimized images.

Leave a request on the UFLEX website if you want your site’s speed checked or need a new, fast website.