When clients come to us with a slow WordPress site, the causes are almost always the same. We have audited hundreds of sites and the same patterns come up over and over. Here are the 10 things we check first — in the order that usually produces the biggest improvements fastest.
Before you touch anything: measure first
Run your site through Google PageSpeed Insights and GTmetrix before doing anything. Note your current LCP, FCP, and total blocking time. Every change you make should be measured against this baseline. Without a measurement, you cannot tell if something helped or made things worse.
1. Hosting
This is the single most impactful variable, and the one most people overlook because they set it up years ago and forgot about it. Shared hosting at $5–$10/month puts your site on a server shared with hundreds or thousands of other sites. When any of them spike, you slow down.
Switch to managed WordPress hosting: Kinsta, WP Engine, Cloudways, or SpinupWP. Budget $30–$80/month. This single change often improves LCP by 1–2 seconds. Everything else on this list becomes easier once the server is fast.
2. Caching
WordPress generates pages dynamically on every request by default — querying the database, running PHP, assembling HTML. Caching stores the finished HTML so it can be served instantly to the next visitor.
For most sites, WP Rocket is the easiest and most effective caching solution ($59/year). It handles page caching, browser caching, file minification, and lazy loading in one plugin. If you are on LiteSpeed hosting, LiteSpeed Cache is free and excellent.
3. Image optimization
Images are almost always the largest assets on a page, and most sites have at least one hero image that is 2–4MB when it should be under 200KB.
- ✓Convert images to WebP format (roughly 30–50% smaller than JPG at the same quality)
- ✓Resize images to the actual display size (a 4000px image displayed at 800px is wasteful)
- ✓Compress images through Squoosh or ShortPixel before uploading
- ✓Use the loading='lazy' attribute on below-the-fold images
- ✓Set explicit width and height attributes to prevent layout shift (fixes CLS)
ShortPixel or Imagify can bulk-convert and compress existing libraries. This is often the fastest win after hosting.
4. Minification and concatenation
WordPress with multiple plugins often loads dozens of separate CSS and JavaScript files. Each file requires a separate network request. Minification removes whitespace and comments; concatenation merges files to reduce requests.
WP Rocket handles this automatically. If you are not using a cache plugin with this feature, Autoptimize (free) is a capable standalone option. Test carefully after enabling — some plugins break when their scripts are concatenated.
5. Render-blocking resources
Scripts and stylesheets that load in the <head> block the browser from rendering the page until they finish loading. Identify these in PageSpeed Insights under 'Eliminate render-blocking resources'.
Solutions: move scripts to load with defer or async attributes; inline critical CSS and defer the rest; load web fonts with font-display: swap.
6. Database bloat
WordPress databases accumulate waste over time: post revisions (often hundreds per post), expired transients, spam comments, unused metadata. This bloat slows every database query.
WP-Optimize or Advanced Database Cleaner can remove this safely. Limit post revisions by adding define('WP_POST_REVISIONS', 5) to wp-config.php going forward.
7. Too many plugins
Every active plugin adds code that runs on every page load. Deactivate and delete plugins you do not actually use. Review your active plugin list and ask: is this functionality used? Could one good plugin replace three mediocre ones?
The number of plugins is less important than what each one does. A well-coded plugin with a narrow function is better than a bloated all-in-one plugin that loads resources on every page even when not needed.
8. CDN (Content Delivery Network)
A CDN stores copies of your static files (images, CSS, JavaScript) on servers around the world. Visitors download assets from the server closest to them rather than your origin server.
Cloudflare's free plan adds CDN functionality, basic DDoS protection, and SSL. For most sites, enabling Cloudflare is a zero-cost speed improvement.
9. Unused CSS and JavaScript
Page builders and theme frameworks often load hundreds of kilobytes of CSS and JavaScript that are used on one page but loaded on all pages. Google's Coverage tool in DevTools shows exactly how much of each file is unused.
Asset CleanUp or Perfmatters can selectively disable plugins and scripts on pages where they are not needed. This is particularly impactful for WooCommerce, which loads checkout scripts on every page by default.
10. PHP version
PHP 8.x is significantly faster than PHP 7.x. Check your hosting control panel for your current PHP version. Many sites still run on PHP 7.4 or older because no one has updated since the initial setup. Upgrading to PHP 8.2 or 8.3 is usually safe for well-maintained themes and plugins, and the speed improvement is measurable.
Before upgrading, check that your theme and all plugins list compatibility with PHP 8.x in their documentation.
The compounding effect: each of these fixes has a modest individual impact. Applied together, they can take a site scoring 30 on mobile to 80+. Start with hosting and images — those two alone often move the needle more than everything else combined.
What to do if the site is still slow after all this
At that point, the problem is usually architectural — a page builder generating too much DOM, a theme with excessive JavaScript, or a WooCommerce install that needs custom optimization. A developer audit is faster than continued experimentation at this stage.
We make WordPress fast — and keep it that way
Every Webicode build targets Core Web Vitals green. If your existing site is slow, we can audit it and fix it.
Get a speed audit