Website performance & speed, explained
Everything you need to know about making your website fast — why it matters, what slows sites down, and how to fix it.
- Difficulty
- Beginner
A slow website costs you visitors, customers, and search rankings. This section explains what page speed really means, why it matters for your business, and what you and your team can do about it — in plain English.
Come here when your site feels sluggish, when someone sends you a scary-looking speed score, or before you add something heavy like a video, a new plugin, or a page full of photos. If your site is slow right now and you want a symptom-first checklist, start with My site is slow.
Quick summary
Speed comes down to a handful of things: your images, your hosting, your plugins and third-party scripts, your fonts, and whether caching is switched on. Measure first, then fix the biggest cause. Start with What slows websites down or How to measure your site's speed.
If you only read three things
- Why website speed matters — the business case.
- What slows websites down — diagnose before you fix.
- Images & page speed — usually the highest-impact win.
Why speed matters
Why website speed matters
How a slow site affects your visitors, your revenue, and your Google ranking.
What is page speed?
A plain-English explanation of what 'page speed' actually means.
Core Web Vitals explained
Google's three measurements of loading, responsiveness and visual stability — and what they mean for you.
How to measure your site's speed
Free tools to check how fast your site is right now.
What slows sites down
What slows websites down
The most common causes of a slow site, ranked by impact.
Images & page speed
Why images are often the biggest culprit — and how to fix them.
How plugins affect speed
More plugins doesn't always mean more problems — but it can.
Fonts & page speed
How web fonts slow things down and what you can do about it.
Improving speed
Caching explained
How a saved copy of your page makes your site faster for every visitor.
Cache plugins explained
WP Rocket, WP-Optimize and Autoptimize compared.
How a CDN speeds up your site
What a Content Delivery Network does and why it helps.
How hosting affects speed
Why your choice of host has a huge impact on performance.
Mobile performance explained
Why mobile speed is different — and why it matters more than ever.
Reference
Performance: realistic expectations
What a good score looks like — and why perfect scores aren't the goal.
Website performance checklist
A practical checklist for keeping your site fast.
Performance terms, explained simply
A plain-English glossary of speed and performance jargon.
When speed becomes a problem
My site is slow
The symptom-first checklist when pages are crawling today.
My changes aren't showing up
Usually caching doing its job — here's how to clear it safely.
How to clear your cache & hard refresh
The 30-second fix to try before anything else.
What to check on your site monthly
Keep speed from creeping back up over time.
Need a hand?
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