How to improve website speed, in the order that pays off.
A slow website loses visitors before they read a word. This guide shows how to measure speed honestly, find the few causes behind most slow pages, and fix them in the order that pays off: images, scripts, fonts, hosting and caching.
- Measure on mobile first, and fix the biggest cause before the small ones.
- Images, scripts and plugins cause most slow pages, and they are fixable.
- Speed is kept, not won once: check it after every change.
6 min readPublished By Domeq Solutions
Why does website speed matter?
People leave pages that feel slow, and most visits now happen on phones, often on a slower connection than your office broadband. A slow page loses the visitor, and it also sends search engines a signal that the experience is poor.
Speed is not one number. It is how soon a page shows something useful, how soon it can be used and whether it jumps around as it loads. Google summarises these as the Core Web Vitals: loading, interactivity and visual stability. Their targets are published by Google and can change, so check the current figures when you test.
A fast page is a polite page: it respects the visitor's time.
What happens when a page loads.
Request
The browser asks the server for the page.
Server answers
Hosting and caching decide how fast.
Files download
Images, scripts and fonts are the weight.
Browser draws
Heavy scripts can hold up what you see.
Page is usable
The visitor can tap, scroll and read.
How do you measure speed honestly?
Measure before you change anything, so that you know whether the change helped. Test the pages that matter most, such as the homepage and the main service or product pages, on the mobile setting of a free tool such as PageSpeed Insights or the Lighthouse panel in Chrome.
Run each test a few times, because results vary. Note the score, and more importantly the specific suggestions and the largest element that loads. Our free website audit also shows how quickly your server starts to answer, which is the first step of every page load.
Speed terms, explained.
- Largest Contentful Paint (LCP)
- How long the biggest visible element, often a photograph or a headline, takes to appear.
- Interaction to Next Paint (INP)
- How quickly the page responds when someone taps or clicks.
- Cumulative Layout Shift (CLS)
- How much the layout jumps around while the page loads.
- Time to first byte
- How long the server takes to start sending the page.
- Caching
- Keeping a ready copy of a page or file so it does not have to be rebuilt every time.
- Content delivery network (CDN)
- A network of servers that delivers your files from a place close to each visitor.
- Render-blocking resource
- A file the browser must load before it can show the page.
Looking for another term? Browse the full glossary.
What should you fix first?
Most slow pages have the same handful of causes. Work through them in this order, because the first ones usually give the largest gains for the least effort.
Seven fixes, biggest gains first.
Resize and compress images
Photographs are usually the heaviest part of a page. Save them at the size they display, in a modern format such as WebP, and compress them.
Load images only when needed
Images below the first screen can load as the visitor scrolls, so the top of the page appears sooner.
Remove what you do not use
Delete unused plugins, themes, scripts and fonts. Each one adds files to download and code to run.
Trim third-party scripts
Chat widgets, trackers and embedded feeds can slow a page badly. Keep only the ones that earn their place.
Limit and optimise fonts
Use one or two typefaces, and only the weights you need, and let text show while the font loads.
Turn on caching and compression
Caching stores ready copies of pages, and compression shrinks files in transit. Most hosts and platforms offer both.
Check the hosting
A slow server delays every page. If the server is slow to answer, no amount of tidying fixes it, and a better plan or a CDN may be needed.
Does the platform change what you can do?
The fixes are the same everywhere, but the way you apply them depends on the platform. A site built on WordPress gains most from fewer plugins, a lean theme and caching. A Shopify store gains most from fewer apps and lighter images. A custom Next.js build starts fast by design, and stays that way when images and scripts are controlled.
See WordPress Development, Shopify Development and WordPress vs Next.js for how each platform handles speed.
Which speed mistakes are most common?
Speed work goes wrong in familiar ways.
Six common mistakes.
Testing only on a fast desktop
Your visitors are on phones and slower connections. Test the way they browse.
Chasing a perfect score
A score is a guide. Fix the problems that real visitors would notice first.
Uploading huge photographs
A photo straight from a camera can be many times heavier than it needs to be.
Installing a plugin for every feature
Each addition costs speed, and some do the same job twice.
Fixing once and never checking again
New content, plugins and scripts slow a site gradually. Review speed every quarter.
Ignoring the server
Cheap, crowded hosting can undo every other improvement.
How do you keep a site fast?
Make speed part of routine care. Resize images before they go up, test new pages and plugins before they go live, and review the main pages every quarter. The website maintenance checklist puts it into the monthly, quarterly and yearly rhythm.
At Domeq, every website is built to a performance score target of 90 or higher, and checked in testing before launch. After launch, Website Maintenance & Optimization keeps the speed work going. Want a first read of where a page stands today? Run the free website audit.
Questions, answered.
Why is my website slow on mobile?
Common causes are oversized images, too many scripts and plugins, heavy fonts, slow hosting and no caching. Phones also have slower processors and connections than a desktop, so problems show up there first.
What is a good website speed score?
Tools score from 0 to 100, and a score in the green range is a good aim. Domeq builds to a performance score target of 90 or higher. A score is a guide, so also watch how the site feels on a real phone.
Does website speed affect SEO?
Yes, as one of many factors. A slow page frustrates visitors and can weaken how a page performs in search. Speed alone does not guarantee rankings, but a slow site is a handicap.
How do I make images load faster?
Resize them to the size they display, save them in a modern format such as WebP, compress them and load those below the first screen only when the visitor scrolls to them.
Do too many plugins slow down WordPress?
Often, yes. Each plugin adds code to load and maintain, and badly written ones can slow a site a lot. Keep only the plugins you use, and prefer a few well-made ones to many.
What are Core Web Vitals?
A set of measures Google uses for page experience: how fast the main content loads, how quickly the page responds to a tap, and how stable the layout is while loading. Google publishes the targets and can change them.
How often should I test my website speed?
After every major change, and at least once a quarter. New content, plugins and scripts slow a site gradually, so regular checks catch the drift early.
Keep reading.
More guides on the same topic, and on the ones around it.
- Website Maintenance Checklist: Monthly, Quarterly, YearlyA website maintenance checklist with the monthly, quarterly and yearly tasks that keep a business site fast, secure and working.Website Maintenance & Optimization
- Website Security Basics for a Small BusinessWebsite security basics for small businesses: why sites get attacked, habits that prevent most problems, what to do after a hack and when to get help.Website Maintenance & Optimization
- What Affects the Cost of a Website in India?What decides the cost of a website in India? Seven price factors, how to compare quotes fairly, and the costs that arrive after the quote.Website Design & Development
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