You have a nice website: good copy, appealing design, clear navigation. But inquiries fall short of your expectations. One cause that is often overlooked: the site loads too slowly — especially on smartphones. That sounds trivial, but it is one of the best-researched connections in online marketing.
The numbers: what studies show — and what they don’t
- Google (2016): The study “The Need for Mobile Speed” looked at more than 10,000 mobile websites and found that 53% of mobile visits were abandoned when a page took longer than three seconds to load. The figure is old and dates from the 3G era, but the direction still holds today: people who have to wait leave.
- Deloitte (2020): The study “Milliseconds Make Millions”, commissioned by Google and based on data from 37 brand websites, found that when the mobile site got 0.1 seconds faster, retail conversions rose by an average of 8.4%, and travel conversions by 10.1%.
- Google ranking: The Core Web Vitals feed into the page experience signals that Google’s ranking systems take into account. Relevance and content quality carry more weight — but when several pages are similarly helpful, a good user experience can make the difference.
Important for context: these are averages, mostly from big brands. How much speed matters in your case depends on your industry, your target audience and your starting point. There is no guarantee. What is clear, though: a slow site hurts you twice. Visitors bounce before they have even seen your offer, and the site has a harder time in search.
What does “fast” actually mean?
Google measures the user experience while a page loads with the Core Web Vitals — three metrics with fixed thresholds. Each one is assessed at the 75th percentile: at least three out of four page views have to meet the threshold.
| Metric | What it measures | Good | Needs improvement | Poor |
|---|---|---|---|---|
| LCP (Largest Contentful Paint) | When does the largest content element become visible? | ≤ 2.5 s | 2.5–4 s | > 4 s |
| INP (Interaction to Next Paint) | How quickly does the page respond to clicks and input? | ≤ 200 ms | 200–500 ms | > 500 ms |
| CLS (Cumulative Layout Shift) | How much does the layout jump around while loading? | ≤ 0.1 | 0.1–0.25 | > 0.25 |
How to measure your website for free
- PageSpeed Insights from Google: shows field data from real Chrome users at the top, provided your site has enough visitors, and below that a lab score from 0 to 100 with concrete suggestions for improvement.
- Google Search Console: the “Core Web Vitals” report shows which groups of pages miss the thresholds.
- GTmetrix: a detailed waterfall analysis of which file takes how long to load.
- Chrome DevTools (F12): the Network tab shows every loaded file with its size, and in the “Lighthouse” tab you can run measurements yourself.
For the lab score, Google’s own color scale applies: 90–100 is good (green), 50–89 needs improvement (orange), below 50 is poor (red). Always measure on mobile as well, and several times, because individual measurements fluctuate. In the end, the field data is what counts, because it shows what real visitors experience.
The most common causes of slow websites
The culprits are almost always the same — and most of them can be fixed without a relaunch.
1. Images that are too large
The classic. A photo straight from a camera or smartphone easily weighs several megabytes. On a website, well under 200 KB is enough for most images, as long as they are delivered in a modern format such as WebP or AVIF and at the size they are actually displayed. Tools: Squoosh, TinyPNG or your system’s automatic optimization, such as the Next.js image component. Images further down the page can load later via lazy loading — but not the large image at the very top, or your LCP gets worse.
2. Too many external scripts
Every tracker, every chat widget, every embedded map loads additional JavaScript. That costs bandwidth and processing time; on older smartphones, responsiveness (INP) suffers most. Check regularly which scripts you really need. Some things can also be loaded only after a click, such as a map or a video — and tracking isn’t allowed to start before consent anyway.
3. No CDN (content delivery network)
Within Germany, the distance to the server only adds a few milliseconds. A CDN is still worth it: it delivers images, scripts and fonts from a nearby node, absorbs traffic spikes and helps a lot if your server is far away. Providers include Cloudflare (with a free entry tier), AWS CloudFront or your hosting provider’s own network. With providers outside the EU, data protection belongs on the checklist too.
4. Outdated transfer protocols
HTTP/2 and HTTP/3 transfer many files in parallel and faster than the old HTTP/1.1. Almost all current hosting providers support at least HTTP/2. To see whether your site uses it, open the Network tab in Chrome DevTools and check the “Protocol” column (“h2” or “h3”).
5. Render-blocking resources
These are CSS and JavaScript files that have to be fully loaded before the browser displays anything at all. The fix: load the CSS needed for the first screen first and the rest later; include JavaScript with “defer” or “async”; limit the number of typefaces and font weights.
6. A slow server
Cheap shared hosting, missing caching or a WordPress install with dozens of plugins mean that even the server’s first response takes a long time. This is called Time to First Byte (TTFB). As a rough guide, Google suggests 0.8 seconds at most. If your value is well above that, caching, a better hosting plan or a plugin cleanup often does more than any image optimization.
Our process at Vagabov Agency
In our website projects, performance is part of the planning, not an add-on bolted on afterward. Projects built on Next.js include the following as standard:
- automatic image optimization via the Next.js image component, in modern formats and the right sizes,
- lazy loading for everything below the fold,
- static generation wherever possible,
- delivery via a CDN,
- measurement with Lighthouse and PageSpeed Insights before going live and after major changes.
Basic technical SEO, including load time optimization, is part of every one of our website packages, not an extra charge on top.
What does this mean for your business?
Nobody can honestly predict how many additional inquiries a faster site will bring you — and neither can we. But you can measure it yourself:
- Record a baseline: Note the Core Web Vitals of your most important pages and your conversion rate — that is, inquiries, bookings or purchases per 100 visits — over at least four weeks.
- Fix the biggest bottleneck: Start with whatever PageSpeed Insights shows as the biggest potential saving — usually images or scripts.
- Compare: Look at a period of the same length after the change. Watch out for seasonal effects, and keep in mind that your analytics can’t record visits from people who haven’t given consent.
- Keep going or stop: Once your values are in the green, each additional millisecond brings less. At that point, working on your content and your offer pays off more.
Our article on comparing your speed with your competitors (in German) shows how to benchmark your site against the competition in just a few minutes. The technical details are in the article on technical SEO and Core Web Vitals with Next.js (in German).
Conclusion: performance isn’t a technical detail — it’s business
A fast website is not a nice-to-have. Load time is one of the levers with the most direct effect on user experience, visibility and inquiries — and you can measure it before and after you invest.
If you want to know what is slowing your website down, just bring your PageSpeed scores to a free initial call. We’ll then discuss which measures are worth it for you.
