A slow website
A slow website loses visitors and is harder to use, but "slow" can mean several different problems. This guide is for site owners who want to find the actual cause before changing anything. It shows how to measure, how to tell a slow server from a heavy page, and how to fix the most common causes.
Measure first
Guessing wastes time. Two free tools tell you where the time goes.
PageSpeed Insights. Open PageSpeed Insights, enter the address of a page, and run the test. It reports how quickly the page loads on mobile and desktop and lists specific problems, such as oversized images or scripts that block the page from showing. Test more than one page: the home page, a typical article or product page, and any page visitors complain about.
Your browser's developer tools. In most desktop browsers, press F12 (or Cmd+Option+I on a Mac), open the Network tab, and reload the page. You see every file the page loads, how big it is and how long it took. Tick the option to disable the cache so you see what a first-time visitor gets.
Write down the results before you change anything, so you can tell whether a fix helped.
Server delay or heavy page?
In the Network tab, click the first entry, which is the page itself, and look at its timing. The key number is time to first byte (TTFB): how long the server takes to start sending the page after the browser asks for it.
| What you see | What it usually means |
|---|---|
| Long TTFB, often more than a second, then everything else loads quickly | The server is slow to build the page: caching, database, PHP or resource limits |
| Short TTFB, but the page takes a long time to finish | The page is heavy: large images, many scripts, fonts or third-party services |
| Both | Work on the server side first, then the page weight |
Common causes and fixes
No caching
Many websites, including those built with WordPress and similar apps, build each page from scratch on every visit by running PHP code and querying a database. Page caching saves the finished page and serves the saved copy to the next visitor, which cuts TTFB sharply. Turn on the caching your website app offers, or install a well-maintained caching plugin. Also make sure browser caching headers are set, so returning visitors do not download the same files again.
Large images
Photos straight from a camera or phone are often several megabytes each. Resize images to the largest size they are shown at, compress them, and use modern formats such as WebP or AVIF where your site supports them. Enable lazy loading so images further down the page load only when the visitor scrolls to them.
Too many plugins and scripts
Each plugin, tracking code, chat widget, font and embedded video adds files and work. Remove anything you no longer use. In the Network tab, sort by size or time to find the heaviest items, and ask whether each one earns its place.
Slow database queries
A database that has grown large, or a plugin that runs inefficient queries, can make every page wait. Clean out old revisions, spam comments and expired temporary data, and remove plugins that run heavy reports or searches on every page. If your app has a query monitoring tool, use it to find the slowest queries.
Outdated PHP
PHP is the programming language many websites run on. Newer supported versions are usually faster and receive security fixes. Check that your site and its plugins support a newer version, then switch. See PHP versions and settings, and take a backup first.
Resource limits
Shared hosting accounts have limits on CPU, memory and the number of processes running at once. When a site reaches them, requests queue up, slow down or fail, sometimes with a 503 error. See Resource limits for how to spot this.
Bot traffic
Automated traffic, such as aggressive crawlers, scrapers or attempts to guess login passwords, can use resources that real visitors need. Check your access logs or visitor statistics for many requests from a few addresses or user agents. Protect login pages, block abusive bots, and use your website app's security tools.
WordPress sites
WordPress has its own set of fixes, from caching plugins to cleaning up the database. See Speed up WordPress.
When to upgrade your plan
Upgrade when the site is already well optimized and still slow, or when it regularly hits its resource limits because of genuine visitors. Signs include limits being reached at busy times, a long TTFB even with caching turned on, and steady growth in traffic. Optimizing first is worth it either way: a lean site runs better on any plan.
Change one thing, test again with the same tools, and compare with your earlier results. That way you know which fix helped, and you can undo one that caused problems.