If you want to speed up WordPress site performance, don’t start by installing a speed plugin. Start by measuring, then fix the biggest problems first. In my experience building WordPress sites since 2013, including 9.5 years building them for every client of a dental marketing agency, slow sites almost always come down to the same few causes, and they’re fixable.
Step 1: Measure before you change anything
Run your home page and your most important service page through Google PageSpeed Insights, on the mobile setting. Note the scores, then note these three numbers, Google’s Core Web Vitals:
| Metric | What it measures | Google’s “good” target |
|---|---|---|
| Largest Contentful Paint (LCP) | How fast the main content appears | 2.5 seconds or less |
| Interaction to Next Paint (INP) | How quickly the page responds when someone taps or clicks | 200 milliseconds or less |
| Cumulative Layout Shift (CLS) | How much the page jumps around while loading | 0.1 or less |
Google says to aim for these at the 75th percentile of page loads, so most real visitors get a good experience, not just your fast office connection.
PageSpeed Insights shows two kinds of data. Field data comes from real Chrome users over the last month, if your site has enough traffic. Lab data is a single simulated test. Use lab data to test fixes quickly, and field data to confirm real visitors noticed.
Step 2: Fix your images
This is the most common problem and the easiest fix:
- Resize before uploading. A photo straight from a phone is often several megabytes and thousands of pixels wide. Most website images never need to be wider than about 2,000 pixels.
- Use modern formats like WebP or AVIF, which are far smaller than JPEG for the same quality.
- Lazy-load images below the fold, but not the main image at the top of the page, which should load straight away.
- Set width and height on images so the page doesn’t jump as they load. That fixes a lot of layout shift.
Step 3: Deal with a heavy theme or page builder
Multipurpose themes and page builders load sliders, animations, icon libraries and layout code on every page, even when a page uses none of it. That’s often the main reason for a slow Largest Contentful Paint and a sluggish response on phones.
Options, from least to most work:
- Turn off unused features in the theme or builder settings.
- Replace sliders and animations at the top of the page with a single fast-loading image and headline.
- Move to a lighter theme or a custom-built one when the current one can’t be made fast.
Step 4: Remove plugins you don’t need
Every plugin adds code, and many add scripts and styles to every page. Go through the list:
- Delete anything inactive.
- Remove plugins that duplicate each other, or that do something your theme already does.
- Replace heavy plugins that load on every page for a feature used on one page.
Test on a staging copy first, so a removal doesn’t break the live site.
Step 5: Add page caching
Caching saves a ready-made copy of each page, so WordPress doesn’t rebuild it from scratch for every visitor. Many hosts include server-level caching; otherwise a reputable caching plugin does the job. Add it after steps 2 to 4: caching makes a lean site fast, but it can only hide part of a bloated one.
Step 6: Check your hosting
Cheap shared hosting can be fine for a small, well-built site. A heavy site on slow hosting suffers twice. If your server response time is slow even on a simple page, the host is the bottleneck. Sometimes the right fix is better hosting, and sometimes it’s a lighter site that doesn’t need it.
Step 7: Measure again
Rerun PageSpeed Insights on the same pages and compare with your notes from step 1. Lab numbers change straight away; field data takes weeks to catch up, because it’s based on real visits over time.
Speed is part of SEO
Google lists page experience among the SEO fundamentals worth getting right, and a fast site keeps visitors who would otherwise leave. If you’re planning a rebuild, building for speed and search from the start is easier than fixing it later; see SEO-friendly web design. And for the local side of getting found, see my local SEO guide for small businesses.
If you’d rather have a developer fix it, that’s what my WordPress development service does.
