Why a slow website costs you customers, and how Google measures it
Short answer: a slow website costs you customers because the people searching for a local business are usually on a phone, often on mobile data, and they have 2 or 3 other results one tap away. If your page is still loading, jumps about or ignores their tap, they go back and choose someone else. Google measures exactly this with 3 Core Web Vitals: how fast the main content appears, how quickly the page responds, and how stable it is while loading. This post explains each one in plain English, with the thresholds Google publishes.
Why speed matters for a local business
Think about how your customers find you. A homeowner with a leaking tap, standing in the kitchen. A parent looking for a dentist between school runs. A manager on a site visit searching for an electrician. None of them are at a desk on fast broadband, and none of them are patient. They are comparing you with the next result.
A slow site loses in 2 ways. Some visitors leave before they see anything, and you never know they came. Others wait, but the site feels clumsy, and that feeling transfers to the business. A site that jumps as you try to tap the call button does not make a tradesman look careful.
The 3 Core Web Vitals
Google publishes 3 measures of how a page feels to a real visitor. Each has a “good” threshold, and Google judges a page by the experience of the slower end of its visitors, the 75th percentile, not the luckiest ones.
| Measure | What it means in plain English | Good | Needs improvement | Poor |
|---|---|---|---|---|
| LCP, Largest Contentful Paint | How long until the main thing on the page, usually the heading or hero photo, has appeared | 2.5 seconds or less | Over 2.5 up to 4 seconds | Over 4 seconds |
| INP, Interaction to Next Paint | How long the page takes to react when someone taps, clicks or types | 200 milliseconds or less | Over 200 up to 500 milliseconds | Over 500 milliseconds |
| CLS, Cumulative Layout Shift | How much the page jumps about as it loads | 0.1 or less | Over 0.1 up to 0.25 | Over 0.25 |
LCP: does the page show up quickly?
LCP is the moment the visitor can see what they came for. On most small business sites that is a large photo or the main heading. If the photo is a 5MB image straight off a camera, LCP is slow, however fast the rest of the page is. Google’s good threshold is 2.5 seconds or less.
INP: does the page respond when tapped?
INP replaced an older measure, First Input Delay, in March 2024. It measures the delay between a tap and the page visibly responding, such as a menu opening or a form field accepting text. Slow INP usually comes from heavy scripts: chat widgets, page builders, tracking tags and sliders, all competing for the phone’s attention. Good is 200 milliseconds or less, which feels instant.
CLS: does the page stay still?
CLS measures the annoying jumps when an image, a banner or a font loads late and pushes the text down. You go to tap “Get a quote” and hit an advert instead. It is a score, not a time, and good is 0.1 or less. The fix is mostly about reserving space for images and banners before they load.
Does speed affect Google rankings?
Yes, but less than people selling speed fixes suggest. Google says page experience, which includes Core Web Vitals, is one of many signals its ranking systems use, and that relevant, helpful content matters more. A fast page with nothing useful on it will not rank. Between 2 pages that are equally relevant, the better experience can help.
The bigger effect is on the customer. Rankings get you the visit. Speed decides whether the visit turns into an enquiry.
What slows small business sites down
The same causes come up again and again.
- Huge images. Photos uploaded at full camera size instead of resized and compressed to a modern format such as WebP.
- Sliders and video headers. Several large images or a video loading before the visitor can read a word.
- Too many plugins and scripts. Each chat widget, review feed, social feed and tracker adds weight and slows taps.
- Page builders. Drag-and-drop builders often load far more code than the page needs.
- Fonts loaded badly. Several font files from another server, causing invisible text or a jump when they arrive.
- Cheap shared hosting. A slow server delays everything before the first byte arrives.
How to test your own site
You do not need to be technical.
- Go to PageSpeed Insights, Google’s free tool at pagespeed.web.dev, and enter your address.
- Look at the top section first. If enough real visitors have used your site, it shows field data from Chrome users, which is what Google actually uses.
- If there is no field data, the lab test below it gives a useful estimate from a simulated phone.
- If you have Google Search Console set up, its Core Web Vitals report shows which pages pass and which do not.
- Then do the human test. Open your site on your own phone, on mobile data, and try to send yourself an enquiry.
How we build for speed
We build to tighter targets than Google’s: LCP under 2 seconds on mobile and CLS under 0.05. Our sites are static, so pages are ready before anyone asks for them, images are resized and compressed, there are no sliders or video headers, and no third-party scripts beyond analytics. That is part of every £399 build, not an extra, and you can see what is included on our affordable web design page.
If your current site is slow, a website redesign is often the quickest fix, because speed problems usually come from how the site was built rather than one setting. Once it is live, fixing anything Google flags is part of the care plan.
Questions to ask yourself
- How long does my home page take to show on my phone, on mobile data?
- Does anything on the page jump as it loads?
- Does my site pass Core Web Vitals in PageSpeed Insights?
- How many widgets, sliders and plugins does my site carry, and does each one earn its place?
- When did anyone last check the size of the photos on my site?
If you would like us to look, send us your web address and we will reply by email within one working hour with what is slowing it down.