How to Improve Website Speed: Check, Fix, Test Again

How to check your website speed

Fixing a slow site starts with measuring it properly. This guide covers the free tools, the targets worth aiming for and the fixes to try in order, from cheapest to most involved.

Test your most important pages on a phone with PageSpeed Insights, then fix the biggest causes first: oversized images, too many plugins or third-party scripts, missing caching and weak hosting. Google's guidance asks for the main content to appear within 2.5 seconds for most visits. Test again after each change so you know which one helped.

Knowing how to improve website speed starts with a reliable measurement of where you stand. Test on a phone, because phones are slower than laptops and mobile connections vary. Test more than the homepage. Pick the page most visitors reach from search, the page your adverts point to and one page that is heavy with images or a form.

These are the tools worth using, all free.

• PageSpeed Insights, from Google. Enter a page address and it reports mobile and desktop results. It shows two kinds of data: measurements from real visitors over recent weeks, which appear only when the page has enough traffic, and a lab test run on a simulated phone.
• The Core Web Vitals report in Google Search Console. It groups your pages as good, needing improvement or poor, based on real visitors, which makes it useful for spotting patterns across the whole site.
• Lighthouse in Chrome DevTools. It runs the same lab test in your own browser, which is handy while you are making changes.
• A real phone on mobile data. Open the page by hand and see how long it takes before you can read the first screen and tap a button. No tool replaces this.

When real visitor data and the lab test disagree, trust the real data for how the site performs and the lab test for finding causes. Scores also move from one run to the next. Test the same page with the same tool before and after each change, and compare the individual measurements rather than chasing a perfect score.

What is a good website load time

No single load time suits every page, because a page can feel loaded in several ways. Google's guidance for Core Web Vitals sets three targets. They are judged on real visits at the 75th percentile, which means three out of four visits should meet the target.

Treat these as targets for the pages that matter, not as a mark for every page on the site. The homepage, the service or product pages and anything your adverts send people to deserve attention first.

Does website speed affect SEO rankings?

Yes, but less than most owners expect. Google uses page experience signals, and Core Web Vitals are among them. A good page experience does not make up for content that fails to answer the search, though. A fast page with little to say will not outrank a useful slower one, and shaving a fraction of a second off a page rarely changes its position by itself.

Where speed matters most is visitor behaviour. A slow page loses people before they read, and mobile visitors on a weak connection leave quickest. Paid traffic makes this worse, since every click that gives up on a slow page was paid for. Speed also forms part of the technical groundwork in a technical SEO audit. The search engine optimisation page describes the search work Liftup offers around it.

What slows a website down

A few causes account for most slow sites. Your test report usually points at them directly.

• Images bigger than they need to be. A photo straight from a camera or phone can be many times the size the page displays. Reports flag these as images to resize or to save in a modern format.
• Third-party scripts. Chat widgets, tag managers, advertising and tracking pixels, social feeds and embedded maps or videos each load code from another server that you do not control. They add up quickly.
• Too many plugins or a heavy theme. Every plugin adds code, and some load on every page whether the page uses them or not. Page builders and multipurpose themes carry code for features you never switch on.
• Slow or crowded hosting. If the server takes a long time to respond, nothing else on the page can be fast. This shows up as a long wait before anything appears.
• No caching. Without it, the server builds each page from scratch for every visitor.
• Too many fonts. Each font family and weight is a separate file to download.
• Autoplay video and large sliders at the top of the page, which put the heaviest content in the place that needs to load first.

How to improve website speed: fixes to try in order

Start with the changes that cost little and carry little risk. None of the first five changes the design.

1. Resize and compress images. Make each image no wider than the space it fills, save photos in WebP or a similar modern format, and compress them.
2. Load images sensibly. Give every image a width and height so the layout does not jump. Let images below the first screen load only as the visitor scrolls to them. Do not do this to the main image at the top, which should load first.
3. Remove what you do not use. Delete inactive plugins, old tracking codes, unused fonts and embeds that do not earn their place.
4. Turn on caching and compression. Most hosts and caching plugins offer both. Check that your site is actually using them.
5. Delay non-essential scripts. Chat widgets and similar tools can load after the page is usable.
6. Check hosting. If the server is slow even on a simple page, a better plan or a server closer to your visitors helps. A content delivery network serves copies of your files from places near the visitor, which matters if most of your audience is far from the server.
7. Look at the theme or builder. If the page is still slow after all of the above, the cause is probably the build itself, which is a developer's job.

Test after every one or two changes. If a page gets slower or breaks, you will know which change caused it.

Why a site is slow on mobile

A phone has a slower processor than a laptop and often a weaker connection, and every script on the page must be downloaded and run on it. A site that feels fine on an office computer can feel slow on a mid-range phone away from Wi-Fi. Mobile lab tests reproduce this by slowing the simulated device and connection, which is why mobile scores are usually lower than desktop ones.

The usual causes on mobile are these.

• Images sized for a desktop screen and sent unchanged to a phone.
• Heavy JavaScript from sliders, widgets and animations, which a phone is slow to run.
• Pop-ups and banners that appear late and push the content around.
• Menus and effects designed for a mouse that behave badly on touch.

Open your site on a real phone on mobile data and note how long it takes before you can read the first screen. If a phone user would give up before that, it is your first priority.

Is a faster website worth paying for?

It depends on what slowness is costing you. If the site brings enquiries or orders, or if you pay for adverts that land on it, speed is worth money, because every visitor lost before the page loads is a visit you already paid for. If the site gets few visits and the slowness is limited to one heavy page, the cheap fixes will do.

The cost follows the cause. Image fixes, plugin removal and caching are small jobs. Moving hosting is bigger. Replacing a heavy theme or rebuilding page layouts is the biggest, and it is usually the point at which a redesign becomes the better route. The guide to website maintenance versus redesign helps you judge where that point is. If you want a developer to find the cause, the website development page explains what Liftup builds and how to start a conversation.

A sensible order is to measure, make the free fixes, measure again and only then ask for a quote for what remains. A good quote names the pages tested, the results before the work and the result the work aims for.

Keep a speed log

Gradual slowdown is how most sites get slow, and it is invisible unless you record it. Keep a simple log with the date, the page, the tool, the mobile results for LCP, INP and CLS, and what changed since the last test. Run the check monthly and after any plugin, theme or content change.

Questions and answers

How do I check my website speed?

Enter a page address into PageSpeed Insights and read the mobile result. Then open Core Web Vitals in Google Search Console to see how groups of pages perform for real visitors. Finish by opening the site on an actual phone over mobile data.

What is a good load time for a website?

Google's guidance for Core Web Vitals asks for the main content to appear within 2.5 seconds, for taps and clicks to respond within 200 milliseconds, and for the layout to shift by 0.1 or less. These targets apply at the 75th percentile of real visits. There is no single figure that suits every page.

Does website speed affect SEO rankings?

Yes, but it is one signal among many, and content that answers the search carries more weight. Speed has a bigger effect on visitors, who leave slow pages before reading. Fix speed as part of good technical groundwork, not as a shortcut to rankings.

What slows a website down the most?

The common causes are oversized images, third-party scripts such as chat widgets and tracking pixels, too many plugins or a heavy theme, slow hosting and missing caching. Your speed report normally shows which ones apply to your pages. Start with images, since they are the cheapest to fix.

Is a faster website worth paying for?

It is worth it when the site brings in enquiries or orders, or when you pay for adverts that send people to it. Try the free fixes first and test again. Pay for developer time when the cause is the theme, the hosting or the way the pages were built.

Why is my site slow on mobile?

Phones have slower processors and weaker connections than laptops, so heavy scripts and large images hurt more. Mobile lab tests also simulate a slower device, which is why scores are lower. Reduce image sizes, remove unused scripts and avoid large sliders and autoplay video.