Website speed: what to measure and improve

A page can load quickly and still respond slowly when someone presses a button. Improving performance means looking at loading and interaction together.

Start with important pages

Check the homepage, a service or product page and the enquiry or purchase journey. Test mobile and desktop. One page score cannot describe the whole website.

Understand the measurement

PageSpeed Insights combines a lab test with real visitor data when enough is available. These results can differ. A single score does not mean every visitor has the same experience.

Look at common sources of weight

Large images, unnecessary video downloads, multiple fonts and third-party scripts can add work for the browser. Check what the page actually uses before adding another optimisation tool.

Compare under similar conditions

Keep a baseline and repeat the test after making changes. Also check forms, navigation and visual elements. Removing code without testing can improve a score while breaking a feature.

Prioritise delays that get in the way of real tasks. Speed is part of the experience, rather than the only measure of success.

Plan images and interactions together

Our own Thermaikos Guide combines photography, an interactive map and motion. For a site like this, performance checks need to cover content-heavy pages and map interactions as well as the homepage. In web development, we consider loading alongside the tasks a visitor needs to complete.

Further reading: PageSpeed Insights.