How to speed up your website: the checks that matter most

A slow site loses visitors, and search engines take speed into account. Most slow sites have the same few problems, and each one can be measured.

1. Measure first

Run the website speed test. It loads the page three times and reports the median, then splits the time into stages: finding the server (DNS), connecting, securing the connection (TLS), waiting for the first byte, and downloading. The biggest stage is where to start.

2. Server response time

The wait before the first byte arrives (often called TTFB) is mostly the server thinking. If it is more than about half a second, the usual fixes are better hosting, a newer PHP version, a page cache, and fewer or faster database queries.

3. Turn on caching

A page cache stores a finished copy of each page, so the server does not rebuild it for every visitor. Browser caching tells visitors’ browsers to keep images, styles and scripts, so a second visit is quick. Look for Cache-Control headers on your files.

4. Compress what you send

Text files (HTML, CSS, JavaScript) shrink by around 70% with gzip or Brotli compression. Most servers offer it as a setting. The speed test shows whether a page is compressed and by how much.

5. Make images smaller

Images are usually the heaviest part of a page. Resize them to the size they are shown at, use modern formats such as WebP or AVIF, and load images below the fold lazily.

6. Fewer, lighter requests

• Remove plugins, scripts and fonts you do not need.
• Combine or delay third-party scripts such as chat boxes and trackers.
• Use HTTP/2 or HTTP/3, which load many files at once. Our check shows which version a site uses.

7. Use a CDN

A content delivery network keeps copies of your files in many countries, so visitors load them from somewhere close. It matters most when your audience is spread across the world.

Check again

Change one thing at a time and re-run the test, so you know what helped. Speed also varies through the day, so compare several runs.

Related guides

• How siteupdown.com checks a website, and what the verdicts mean
• Uptime percentages explained: what 99.9% really means
• 500, 502, 503 and 504 errors: what server errors mean

Last updated 2 November 2026. Written by the siteupdown.com team. Spotted a mistake?

← All help guides