For the operator who ran their site through PageSpeed Insights and got
back a red report full of acronyms. The two guides here explain what
each metric measures, then walk through the free, standards-based
fixes that actually move them.
After this series: you understand LCP, INP, CLS, TTFB, FCP, and
TBT well enough to read a PSI report without Googling; you have a
concrete checklist of image, script, compression, caching, font, and
bot-blocking changes to apply; and you can point at before/after
numbers to prove the fixes worked.
Work through the steps in order. Each one is small enough to do in under an hour, produces a measurable delta on PageSpeed Insights, and costs nothing beyond your own time. Step 10 covers server-level hardening — not strictly a “speed” fix, but a site getting hammered by bad bots is a slow site, so it belongs on the same list.
New to the metric names below? See Core Web Vitals: what PageSpeed is actually measuring first — LCP, INP, CLS, TTFB, and TBT are explained there in plain terms.
...
The fixes for everything below live in the companion piece: How to make your website faster without buying anything.
The three that feed ranking Core Web Vitals are a set of standardised measurements Google uses to quantify real-world user experience on a webpage. Introduced in 2020, became a confirmed Google Search ranking signal in 2021. Three metrics:
Metric What it measures Good threshold LCP Loading performance Under 2.5 s INP Interactivity Under 200 ms CLS Visual stability Under 0.1 The three that don’t (but are useful anyway) The others covered below — TTFB, FCP, TBT — are supporting metrics. They don’t affect rankings directly but they’re diagnostically useful: they tell you why your Core Web Vitals are poor.
...