Thirty minutes. No pitch. Just a map of what your marketing is missing. Send your brief →
FIELD GUIDE 17
The site speed checklist
Site speed is a tax you pay on every visitor, and it is charged before they have read a single word about you.
You do not need a statistic to believe that a slow site loses people. You do need to know what to measure and which fixes are worth the money, because most speed advice is written for engineers optimising at a scale that does not apply to a twelve-page service business site.
What to measure
Google’s Core Web Vitals are the right target because they are what Google itself uses, they are measured on real visitors rather than a lab test, and they map to things a customer actually experiences.
| Metric | What the visitor feels | Good |
|---|---|---|
| LCP Largest Contentful Paint | How long until the main thing appears | Under 2.5 seconds |
| INP Interaction to Next Paint | How long until the page reacts when tapped | Under 200 milliseconds |
| CLS Cumulative Layout Shift | Whether things jump around while loading | Under 0.1 |
MEASURE ON A PHONE, ON MOBILE DATA
Test on an actual mid-range phone on a normal connection, not on your office wifi on a desktop. The desktop number is the one that makes everyone feel fine and explains nothing.
The five fixes that account for most of the gain
Images
Almost always the single biggest problem on a service business site, and almost always the easiest to fix.
Serve modern formats, size them to how they are actually displayed, and lazy-load anything below the fold. A 4MB photo of a finished bathroom scaled down by the browser is the classic case.
Too many plugins and scripts
Every plugin, chat widget, tracking pixel, popup tool and font loader adds weight and blocks rendering.
Audit them. Remove anything nobody uses. Chat widgets and popup builders are usually the worst offenders and are frequently installed and forgotten.
Fonts
Custom fonts commonly block text from appearing at all. Limit to two weights, self-host where you can, and make text render immediately with a fallback rather than waiting.
Hosting and caching
Cheap shared hosting has a floor you cannot optimise past. If the server takes 900ms to respond before anything else happens, no front-end work will save you.
Turn on page caching. On WordPress this is one plugin and it is frequently the single largest improvement available.
Layout stability
Set explicit dimensions on images and reserve space for anything injected later, such as banners and embeds. This costs nothing and fixes most CLS problems.
The order to do it in
- Run a Core Web Vitals test on your busiest page, on mobile. Write down all three numbers.
- Find your largest images and fix those first. This alone often moves LCP under the threshold.
- List every plugin and third-party script. Delete anything not actively used.
- Turn on caching if it is not already on.
- Set image dimensions to stop layout shift.
- Re-test. If LCP is still poor and images are fixed, the problem is your hosting.
WHEN TO STOP
Once you are inside the thresholds, stop. Going from 2.4 seconds to 1.9 seconds will not change your enquiry count, and the effort is better spent on the homepage checklist. Speed is a hygiene factor, not a growth lever.
FIG. 03 · SOURCES, CHECKED 2 AUGUST 2026
Every number above was traced to its primary source before publication. Where a widely repeated figure could not be verified at the source, it was cut rather than repeated.
- VerifiedGoogle, Core Web Vitals thresholds LCP under 2.5s, INP under 200ms, CLS under 0.1, as published by Google and used in its own page experience reporting.
- UnverifiedConversion-rate multipliers deliberately omitted Widely quoted claims such as "1 second loads convert 3x better than 5 second loads" come from aggregate studies across unrelated sites and do not transfer to an individual small business. The thresholds above are actionable without them.
RANKTHREAD
Fast is the floor, not the strategy
Speed will not win you customers. Being slow will quietly lose them before you get a chance to say anything, which is a different and cheaper problem to solve.
RANKTHREAD
Get the next one
We publish a new field guide most weeks. Plain method, sources cited, no pitch. Leave your address and we will send the next one.
