Website speed: how to measure it on mobile and what slows it down

A slow website makes it harder for customers to read, browse and contact you, especially on a phone. To improve it, first measure how the site loads for visitors, then find what slows it down. The cause is often simple: heavy photographs or third-party scripts that load before the content.

A quick check you can do yourself

1. Open the site on your phone using mobile data, not Wi-Fi.
2. Note how long it takes before you see the main heading and image.
3. Tap the menu and a button. Does the page respond straight away?
4. Watch whether text or buttons move while the page is loading.

These observations match the three measurements Google uses for page experience.

What Core Web Vitals measure

Core Web Vitals are three measurements describing how visitors experience a page. According to web.dev, a page is rated good when these values are met for at least 75% of visits:

• LCP, loading: the largest visible element, usually the main image or heading, appears within 2.5 seconds.
• INP, responsiveness: the page responds to a tap or click within 200 milliseconds.
• CLS, visual stability: the layout does not shift unexpectedly while loading; the value should be 0.1 or less.

How to measure with PageSpeed Insights

Go to PageSpeed Insights, enter your address and choose the mobile result. The report has two parts:

• Real-user data: shown when the site has enough visits, and reflects the actual experience.
• Lab test: a single test under simulated conditions. It helps find causes, but the result varies from one run to the next.

Do not focus only on the 0 to 100 score. Check which measurement fails and read the suggestions linked to it.

How to test on mobile networks in Albania

Almost all your visitors arrive on a phone: according to INSTAT, in 2025, 99.9% of internet users in Albania went online by mobile phone. The speed they get depends on the operator, where they are and the signal. 5G is expanding, but according to AKEP data for the first reporting period of 2026, as reported by the operators themselves, it covered about 60% of the population on Vodafone and 70% on One, and up to 36% of the territory (Monitor, in Albanian). Outside cities and inside buildings, many clients open your website on 4G or a weak signal.

Test on a phone, in real conditions

1. Both networks: test with one phone on Vodafone and one on One, or ask a colleague on the other operator.
2. Three places: in the city centre, inside a building where the signal is weaker, and in the area where your clients live or work.
3. As a new visitor: turn off Wi-Fi and open the site in a private tab, so the browser does not reuse files from an earlier visit.
4. Measure what clients see: with a stopwatch, note when the heading and main image appear and when you can tap the main button. Test the form or booking too.
5. Repeat: run at least three tests in each place and note the slowest result as well, not just the best.

Simulate a weak connection on a computer

In Chrome, the developer tools (DevTools) offer fast 4G, slow 4G and 3G options in the Network tab. Choose slow 4G and reload the page to see how it behaves on a weak signal. PageSpeed Insights also tests the mobile version on a simulated “Slow 4G” connection: 150 milliseconds of latency, 1.6 Mbps download and a processor four times slower. This gives you a consistent point of comparison between tests.

How much data the page downloads

At the bottom of the Network tab, Chrome shows how much data was transferred. A heavy page opens more slowly on a weak signal and uses more of the client’s data plan. Photographs are often the largest part; we explain below how to reduce them. If the page is slow even before anything appears, see the point about the server.

Illustrative example: recording your tests

The figures are illustrative. When you see large differences between places or operators, start fixing the pages that bring the most clients, such as the homepage or service pages.

The most common causes on business websites

Unprocessed photographs

A photograph from a phone can be several megabytes. On a website it should load at the size it is displayed and in a web-friendly format such as WebP. Images further down the page can load only when the visitor scrolls near them.

Third-party scripts

Chat widgets, embedded videos, maps and tracking or advertising code all add work for the browser. Keep only the ones you use and, where possible, load them after the main content appears.

Too many extensions or a heavy theme

On sites with an administration panel, each extension can add code to every page. Remove the ones you do not use and check whether the theme loads features you do not need.

A slow server response

If the delay happens before anything appears, the problem may be the hosting or the way pages are generated. Ask your provider about page caching and server location. See our hosting guide as well.

Elements without set dimensions

Images, banners and ads without a set width and height push the text down as they load. This raises CLS and can make a visitor tap the wrong button.

What you can fix yourself and what needs a developer

You can resize photographs before uploading them and remove third-party tools you no longer use. Changes to the theme, code, script loading and hosting usually need a developer. After every change, measure the same pages again and test the forms, menu and main features.

How we can help

We first check what slows the site down and which pages matter most to your customers, such as the home page, services or products. Then we propose fixes that suit how the site is built. A site can often be improved without rebuilding it from scratch. See website maintenance or send us your website address.