Tag: speed up mobile website for higher booking conversion rates

You have never seen your own site the way a customer does. You are on wifi, with everything cached, on a laptop.

TL;DR Google’s threshold is 2.5 seconds for main content, measured at the 75th percentile on mobile. Oversized images cause most failures. Compress them, defer your scripts, delete dead widgets. Usually an afternoon.

Measure before you touch anything

Run your booking page and your top service page through Google PageSpeed Insights. Read the mobile score only. Desktop is flattering and irrelevant.

Record three numbers

Metric	Good	What it means
LCP (Largest Contentful Paint)	Under 2.5s	When the main content appears
INP (Interaction to Next Paint)	Under 200ms	How fast it responds to a tap
CLS (Cumulative Layout Shift)	Under 0.1	How much things jump around

Google measures these at the 75th percentile, meaning it has to be fast for most visitors, not the best-case one.

Then scroll down in the report. It names the specific files causing the delay. That list is your work order.

Images cause most of it

The usual pattern: someone exports a photo straight from a camera, uploads it, and the browser scales it down to fit a phone. The visitor downloads a file sized for a billboard to look at something the size of a playing card.

The fix, in order

1. Resize before uploading. Export at roughly twice the display width, no more.
2. Convert to WebP. Typically much smaller than JPEG at the same visual quality.
3. Compress. Free browser tools like Squoosh do this with no install.
4. Add loading="lazy" to every image below the fold.
5. Set explicit width and height on every image tag, which prevents layout shift.

Use	Width	Target size
Hero	1600 to 2000px	under 300 KB
In-page photo	800 to 1200px	under 150 KB
Thumbnail	400px	under 50 KB
Logo	Actual display size	under 30 KB

This alone fixes most local business sites.

Script deferral

Scripts block rendering. The browser stops building the page to run them.

• Add defer to any script that does not need to run before paint. That is most of them.
• Add async to independent third-party scripts like analytics.
• Move tag managers below the fold where the platform allows.
• Delay chat widgets until the user interacts or scrolls. Chat tools are among the heaviest things on a typical site and almost nobody needs them in the first second.

Delete what you are not using

Sites accumulate. Audit what actually loads.

Common dead weight

• Chat widgets from a service you cancelled.
• Two or three analytics tools when one would do.
• A popup builder used once for a promo two years ago.
• Social feed embeds that pull a full script to show three posts.
• Review carousels calling an external API on every load.
• Font files for weights you never use.

How to find them. In PageSpeed Insights, look at the third-party summary. Anything you do not recognise or do not use, remove.

Fonts, the quiet one

A custom font is a file that must download before text renders in it.

• Limit to two families and the weights you actually use. Every extra weight is another file.
• Add font-display: swap so text renders in a fallback immediately and swaps when the font arrives.
• Self-host rather than calling a third-party font service, which adds a connection.

The booking flow specifically

Speed on the booking page matters more than anywhere else, because that visitor already decided.

• Load the booking widget on interaction, not on page load. Show a button, load the calendar when tapped.
• If your scheduler is an iframe, lazy-load it.
• Test the whole flow on cellular, not wifi, in an incognito window.
• Time it end to end. Landing to confirmed booking. Anything over 60 seconds is losing people.

The realistic order of work

Priority	Task	Effort	Impact
1	Compress and resize all images	Afternoon	Highest
2	Lazy-load below-fold images and embeds	1 hour	High
3	Remove unused widgets and scripts	1 hour	High
4	Defer remaining scripts	1 hour	Medium
5	Fix fonts	30 min	Medium
6	Delay chat widget	30 min	Medium

Then measure again. Same pages, same tool, and compare.

What to ask whoever maintains your site

Three questions that produce useful answers without you needing to understand the replies in detail.

• “What is our mobile PageSpeed score and our LCP?” A competent answer has actual numbers.
• “Are our images sized for how they display?” This is the most common cause and the easiest to confirm.
• “What third-party scripts are loading that we do not use?”

Run your booking page through PageSpeed Insights right now on mobile. Whatever it names as the top blocking file is your afternoon, and it is usually a photograph.

Don’t have the time? [BOOK A CALL]