Why a website is slow and what can be fixed in a day

A slow website is rarely the result of one big mistake. It is usually the sum of small decisions made over the years: one more image, one more plugin, one more tracking script. The good news is that this is also why it can be fixed piece by piece.

Why speed matters

• Visitors leave. Someone waiting more than a few seconds on a phone goes back to the search results and clicks the next one.
• Google takes it into account. Speed and visual stability are part of how the search engine assesses page experience.
• Ads cost more. You pay for the click even when the visitor leaves before the page loads.

How to measure

Our Page speed tool runs Google’s measurement for mobile and desktop and shows the full report. Three numbers matter most:

• LCP (Largest Contentful Paint): how quickly the main content appears. Good is up to 2.5 seconds.
• INP (Interaction to Next Paint): how quickly the page responds to a tap or click. Good is up to 200 milliseconds.
• CLS (Cumulative Layout Shift): how much content jumps while the page loads. Good is up to 0.1.

Two notes before you start fixing. First, look at the mobile result, because it is measured on a slower device and slower connection and is almost always worse. Second, a single measurement is not reliable: the same page measured three times in a row can get noticeably different numbers. Measure several times and look at the middle value.

The six most common causes

1. Oversized images. A photo from a phone or camera, four thousand pixels wide, shown in a frame four hundred wide. The browser downloads all of it, then shrinks it. This is the most common single cause and the easiest fix.

2. Render-blocking resources. Style and script files in the head that must be downloaded before anything is shown. Until they arrive, the visitor looks at a white screen.

3. Third-party scripts. Analytics, chat, ad pixels, maps, embedded videos, cookie notices. Each comes from someone else’s server and each takes up processor time. On many sites they make up more than half of the total load, and some of them are no longer used by anyone.

4. Fonts. Four font families in six weights means around twenty files. Until they arrive, the text is invisible or jumps when the font is swapped.

5. A slow server. If the server needs a second to even start sending the page, everything else starts a second behind. Common causes are cheap shared hosting, caching that is not configured and a content management system with many plugins.

6. Too many plugins and a heavy theme. A theme that supports every possible layout loads the code for all of them, although you use one. Every plugin brings its own styles and scripts, on every page.

What can be solved in one day

1. Resize and convert images. Reduce them to the width at which they are displayed and save them in a modern format (WebP or AVIF). The effect is often the largest of all the steps.
2. Turn on lazy loading for images below the first screen, so they are downloaded only when the visitor gets close.
3. Set dimensions on images and embedded frames, so the browser reserves the space and content does not jump.
4. Turn on caching and compression on the server or through a content delivery network.
5. Remove what is not used. Plugins, old tracking scripts, fonts and weights that appear nowhere.
6. Defer third-party scripts that are not needed for the first view. A chat or map can load when the visitor needs it.
7. Preload the main font and allow text to show in a fallback font until the real one arrives.

Measure again after each step. That way you see what really helped and do not spend time on changes with no effect.

What takes more work

• Replacing a heavy theme with a lighter one or building your own.
• Moving to better hosting when the server is the bottleneck.
• A page assembled in the browser. If content is fetched and put together only after scripts load, the visitor and the search engine see an empty page for a long time. Preparing pages in advance, on the server or at build time, helps here.
• A web shop with a large catalogue, where the slow part is database queries, not rendering.

Common misconceptions

• “It is fast on my computer.” You have a fast connection, a powerful computer and the page in cache. A visitor arriving for the first time on a phone has none of those.
• “The score has to be 100.” The score is a summary, not a goal. What matters is that the three main numbers are in the green and that the page does its job. A page scoring 85 that sells is better than one scoring 100 that does nothing.
• “A speed plugin will fix it.” A plugin can turn on caching and compression. It cannot shrink a five-megabyte image or remove ten scripts you added yourself.

An example

This website is built so that styles are delivered inside the page itself, images come in several sizes and scripts load only where they are needed. In Google’s measurement it regularly scores between 95 and 100 on mobile. It is not a special trick, but a matter of thinking about speed from the start, not after launch.

Measure your site with our tool. From the results you can send an inquiry with the measured scores in one click, and we will tell you what we would fix first. Read more about how we build websites in the description of our web solutions.