How to read your speed test results and decide what to fix first
Look at the mobile result first and at Largest Contentful Paint before the overall score. The score is a weighted summary; the individual metrics tell you what visitors actually wait for. Mobile tests simulate a slower device and network, so problems show up there earlier than on desktop, and phone visitors are the ones most likely to give up on a slow page.
Read the metrics in pairs. A slow LCP with a fast First Contentful Paint usually means the page starts quickly but its main image or headline block arrives late. A high Total Blocking Time points to heavy JavaScript: sliders, chat widgets, tag managers and third-party embeds are common causes. A poor CLS means content moves while loading, typically images without set dimensions or banners inserted above existing text. The loading timeline shows the order in which things appear, which helps you see which element holds the page back.
Then use the Opportunities list, which estimates savings per item, and start with the change that affects the biggest element on screen. Diagnostics are useful context but rarely the first fix. Run the test two or three times: results vary between runs because network and server response time vary, and a single run can mislead. Our audits run Lighthouse from Frankfurt, so a server located far from Europe will show extra delay that your local visitors may not feel.
A worked example: a product page scores 58 on mobile with an LCP of 4.8 seconds, while CLS is fine. The timeline shows the hero photo appearing last, and Opportunities lists a large, unoptimised image. Resizing it, serving a modern format and preloading it is a single change that addresses the main problem, so it goes first; trimming unused scripts comes second. After the fix, retest the same URL on mobile and compare. With a free account you can schedule the audit and get an alert if the score drops again after a future release.