Step 1: measure

Test the pages that matter most: the home page, a typical article or product page, and the checkout or contact page. Write the results down before you change anything.

Step 2: speed up the server response

The time to first byte (TTFB) is how long the server takes to start sending the page. If it is above about 0.8 seconds, fix it first, because everything else waits for it.

• Turn on page caching, so pages are sent ready-made instead of built by PHP for every visitor.
• Use the newest PHP version your site supports, with OPcache on.
• Add an object cache such as Redis for dynamic sites. See our Redis Manager guide.
• Clean up the database. See our database performance guide.

Step 3: fix images

• Resize images to the size they are displayed. A 4,000-pixel photo shown 800 pixels wide wastes most of its weight.
• Compress them, for example with Squoosh, or a CMS plugin that does it on upload.
• Serve WebP or AVIF, which are much smaller than JPEG and PNG.
• Lazy-load images below the first screen, but not the main image at the top.
• Set width and height on images, so the layout does not jump while they load.

Step 4: reduce JavaScript and CSS

Scripts are the main reason pages feel slow to respond on phones. Remove plugins, widgets and trackers you do not need. Load the rest with defer or delay them until the user interacts. Keep fonts to one or two families and use font-display: swap.

On modern HTTP/2 and HTTP/3 connections, merging all files into one big bundle is no longer always faster. Test before and after if a plugin offers to combine files.

Step 5: turn on compression and browser caching

Most hosting already compresses text files with Gzip or Brotli. Check the content-encoding header in the Network tab. Static files should have long cache times, so repeat visitors do not download them again. Caching plugins and CDNs set this for you.

# Check compression and cache headers for a stylesheet
curl -sI -H "Accept-Encoding: br,gzip" https://example.com/wp-content/themes/theme/style.css | grep -iE "content-encoding|cache-control"

Step 6: use a CDN

A CDN serves images, scripts and styles from locations close to your visitors, which helps most when they are far from your server. See our CDN guide and our Cloudflare and cPanel guide.

Step 7: check the hosting

If the server response stays slow after caching, the site may have outgrown its plan. Signs include hitting CPU or memory limits in cPanel’s resource usage, and slow pages at busy times only. A larger plan or a Cloud VPS gives the site dedicated resources. Our mobile optimisation guide covers the mobile side.

Speed checklist

• ✓ Page caching on, and current PHP with OPcache.
• ✓ Images resized, compressed and in modern formats.
• ✓ Unneeded plugins and scripts removed; the rest deferred.
• ✓ Compression and browser caching active.
• ✓ CDN in place for visitors far from the server.
• ✓ Results measured before and after each change.