What is caching in WordPress? Caching means saving a ready-made copy of something so it doesn’t have to be built again. Instead of WordPress running code and database queries for every visitor, the server hands over a saved copy of the page in a fraction of the time.
Turning on caching is usually the single biggest speed improvement for a WordPress site. It’s also the source of the confusing “I changed it but the site still shows the old version” moments.
Here’s how the different types work and which ones you need.
Why WordPress needs caching
WordPress builds pages on the fly. Each time someone visits, it loads PHP code, asks the database for content, settings and menus, and assembles the HTML.
That’s flexible, but slow when repeated thousands of times. Most pages look the same for every visitor, so building them from scratch each time is wasted work.
The four types of caching
1. Page caching
The server saves the finished HTML of each page and serves it directly to the next visitor. This has the biggest effect on load time and on Time to First Byte.
How to get it: many hosts provide it at server level, which is the best option. Otherwise, use one well-supported caching plugin.
2. Browser caching
The visitor’s browser keeps files like your logo, CSS and JavaScript, so it doesn’t download them again on the next page or the next visit.
How to get it: most hosts and caching plugins set this up for you.
3. Object caching
Saves the results of database queries in memory, using tools such as Redis or Memcached. It helps most where pages can’t be fully cached: the WordPress dashboard, logged-in users, WooCommerce carts and membership areas.
How to get it: your host must support it. Many managed WordPress hosts offer it as a switch.
4. CDN caching
A content delivery network keeps copies of your files, and sometimes whole pages, in data centres around the world, so visitors download them from somewhere nearby.
How to get it: some hosts include a CDN. You can also add one separately.
Which ones do you need?
| Site type | What to use |
|---|---|
| Brochure or service site | Page caching and browser caching. Add a CDN if visitors are spread out. |
| Blog or content site | Page caching, browser caching and a CDN. |
| Online shop or membership site | All of the above, plus object caching, with cart, checkout and account pages excluded from page caching. |
Setting it up without breaking anything
- Check what your host already does. If the host has server caching, you may not need a caching plugin at all. Running both can cause conflicts.
- Use one caching plugin only. Two caching plugins fight each other.
- Start with the basics. Page caching and browser caching first. Test.
- Add optimisation settings one at a time. Options like combining, minifying or delaying JavaScript can break menus, sliders and forms. Turn on one, test the site on mobile, then the next.
- Exclude dynamic pages. Cart, checkout, my account and any page that shows personalised content must not be cached.
- Test forms afterwards. Some forms break when the page is cached. See contact form not sending emails if yours stops working.
“I updated the page but it hasn’t changed”
That’s caching doing its job a little too well. Clear the caches in this order:
- Your caching plugin or host’s cache.
- The CDN cache, if you use one.
- Your browser, or simply check in a private window.
Most caching tools clear a page automatically when you update it in WordPress. If changes still don’t appear, something in the setup needs adjusting.
When caching isn’t enough
Caching hides a slow server well, but it can’t fix everything:
- The first visit after the cache clears is still slow.
- Logged-in users and shop carts can’t use page caching.
- Heavy images and scripts still have to download.
If your site is still slow with caching on, look at hosting, images and plugins. My guide to why your WordPress site is slow covers each. For how caching affects the scores Google measures, see Core Web Vitals explained.
Setting up and tuning caching is part of my WordPress support and maintenance work.
Frequently asked questions
Is a caching plugin enough to make my site fast?
It’s often the biggest single improvement, but not the whole fix. Slow hosting, huge images and too many scripts will still hold the site back.
Can caching break my website?
Basic page caching rarely does. Aggressive optimisation features, like combining and delaying JavaScript, are what usually break things. Turn them on one at a time and test.
Should I cache my WooCommerce shop?
Yes, but exclude the cart, checkout and account pages. Product and category pages can be cached normally.
Why is my WordPress dashboard still slow?
The dashboard is never page cached. A slow admin points to the server, a heavy plugin or a large database. Object caching often helps.
About the author
Vincent Earl Panoncial is a WordPress developer and the founder of VEP Studio. He has built and maintained 100+ WordPress websites, most of them at digital marketing agencies, and now works directly with businesses on development, maintenance and webmaster services.
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Featured photo by Julian Hochgesang on Unsplash.
