How do you measure speed? Free and in one minute
Go to PageSpeed Insights (pagespeed.web.dev), paste your domain and look at the mobile tab, not desktop: Google ranks with the mobile version and that's where sites break.
The two numbers that matter: LCP (main content should appear in under 2.5 seconds) and CLS (the page shouldn't jump while loading; under 0.1).
Cause 1: unoptimized images
It's the most common cause and the cheapest to fix. On a single site I audited I found 40 of 55 images unoptimized: multi-MB camera photos where 80 KB would do.
The fix: modern formats (WebP or AVIF), dimensions matching the real on-screen size, and lazy loading for anything below the fold.
Cause 2: too many scripts and plugins
Every plugin, chat widget, pixel and slider adds weight and blocks loading. The most extreme case I measured: a site whose main content took 45.1 seconds to appear on mobile. After the rebuild, 1.7 seconds: 26 times faster.
List everything your site loads and ask what's earning its place. What isn't, goes.
Cause 3: hosting and architecture
An oversold shared host, no CDN or a heavy theme puts a floor under your load time that no image optimization can break. Sometimes rebuilding pays: a 2018 WordPress I migrated to a static site went from 7.9 to 0.6 seconds of LCP.
Why does it matter? It's not just impatience
According to Google's data, the probability of a visitor bouncing rises 32% when load time goes from 1 to 3 seconds. Speed is also a ranking signal: a slow site shows up less and converts less, at the same time.
Quick check
- 01Measure your domain on PageSpeed Insights, mobile tab
- 02Note your LCP: over 2.5 seconds means there's work to do
- 03Check the weight of your largest images
- 04List plugins and scripts: remove what you don't use
- 05Measure again after every change
Save this list and run it against your own site.
Frequently asked questions
What counts as a good load time?
Main content visible in under 2.5 seconds on a phone. That's the threshold Google uses to consider a page fast, and you can measure it free on PageSpeed Insights using the mobile tab.
Why is my site fast on my computer but slow on phones?
Because your computer has a better connection and more power than your average visitor's phone, and your browser already has the site cached. Google ranks with the mobile version: that's the measurement that matters.
Does a caching plugin fix a slow site?
It helps, but it can't compensate for multi-MB images or an excess of scripts and plugins. Measure what's actually slowing your site first; caching is one more layer, not the underlying fix.
Does speed affect my Google ranking?
Speed is a ranking signal: a slow site shows up less. It also loses visitors before showing anything: according to Google's data, bounce probability rises 32% when load time goes from 1 to 3 seconds.