1. A fast website offers a better user experience
Nobody likes waiting. When a page loads slowly, images appear late or parts of the page jump around while loading, frustration arises. That certainly applies on mobile or with a slower internet connection.
A fast website lets visitors immediately do what they came for: view information, compare products, fill in a form or make a purchase. Performance therefore goes beyond just the total load time of a page and is an important part of a good user experience.
Google uses the Core Web Vitalsfor this, among other things. These measure three important aspects of the user experience:
- Largest Contentful Paint (LCP): how quickly the most important content becomes visible;
- Interaction to Next Paint (INP): how quickly a website responds when a user interacts with it;
- Cumulative Layout Shift (CLS): how stable the page remains during use.
A technically fast website must therefore not only appear quickly, but also respond smoothly and remain visually stable.
2. Speed can contribute to higher conversion
Every extra delay creates a moment at which a visitor can drop off. That is especially important for websites where visitors have to perform an action. Think of requesting a quote, booking an appointment, filling in a form or completing an order.
In e-commerce, performance can therefore directly influence revenue. Speed plays a role on a B2B website too. If a potential customer lands on a landing page from Google or LinkedIn and first has to wait before the most important information becomes visible, the customer journey starts with unnecessary friction.
Studies and practical examples collected by Cloudflare about website performance and conversion show that faster pages are generally associated with better conversion results. That doesn't mean every millisecond automatically yields extra revenue. Conversion is determined by many more factors, such as the offer, the content, ease of use and trust in an organization.
Speed mainly ensures that poor performance doesn't stand between the visitor and the desired action.
3. Website speed plays a role in SEO
Website performance is also relevant for SEO. Google uses Core Web Vitals within its ranking systems to assess aspects of the user experience. A fast, stable and responsive website thereby contributes to a good page experience.
A faster website does not automatically rank higher in Google, however.
In its explanation of page experience and search results Google emphasizes that there is no single separate page experience signal that determines the ranking. The ranking systems use various signals. Good Core Web Vitals therefore do not guarantee a high position in search results.
Good content, alignment with search intent, authority and other SEO factors remain important. Performance should therefore not be seen as a trick to rank higher in Google. It is part of a technically healthy website that functions well for both users and search engines.
4. A fast website can be more efficient
Performance also has consequences behind the scenes. Large images, unnecessary scripts, inefficient code and large amounts of data can cause a website to use more resources than needed. A well-optimized website therefore tries to load only what is actually needed.
Think, for example, of:
- images in modern formats and appropriate sizes;
- caching;
- efficient front-end code;
- as little unnecessary JavaScript as possible;
- lazy loading where it makes sense;
- a good hosting and infrastructure setup;
- efficient use of APIs and external scripts.
That this is not a theoretical problem is shown by the Web Almanac 2024 by HTTP Archive. It names images and JavaScript as important contributors to the weight and the number of requests of modern web pages. The typical mobile page made dozens of separate requests in 2024 to fetch all necessary files.
By serving images at the right size, removing superfluous scripts and loading only necessary resources, data traffic and the load on the browser can be limited. Lazy loading can also prevent images outside the visible part of the page from being loaded immediately.
For a relatively small website the financial difference may be limited. But for websites and digital platforms with a lot of traffic, more efficient software can certainly make a difference for the required server capacity, infrastructure costs and scalability.
How fast should a website be?
To make website performance measurable, you can look at the Core Web Vitals. According to Google's current guidelines for Core Web Vitals 2024 (still current) the following values count as good:
- LCP: at most 2.5 seconds;
- INP: at most 200 milliseconds;
- CLS: at most 0.1.
This is judged at the 75th percentile of measured page views, separately for mobile devices and desktops. That means at least 75% of visits must fall within the recommended limit.
That last point is important. A website that opens lightning fast on a developer's laptop doesn't necessarily deliver the same performance for real visitors. Devices, browsers, internet connections and locations differ. That is why it is wise to also look at real-user data besides technical tests.
How can you test your website's speed?
A well-known first step is Google PageSpeed Insights. With it you can see how a page performs and where possible technical improvement points lie.
According to the official documentation from Google PageSpeed Insights combines two kinds of data:
- Field data: real-world data from real Chrome users from the Chrome User Experience Report, when sufficient data is available;
- Lab data: a Lighthouse test under controlled conditions, intended to investigate technical problems.
Field data helps you understand what real users experience. Lab data helps developers find and analyze technical improvement points. Want to know more about the different measurements and what FCP, LCP, TBT, CLS and other scores mean? Then read our explanation of Google Lighthouse and the most important performance metrics.
For a complete picture of website performance you therefore want to look at both.
A perfect score should never become a goal in itself. A score of 100 doesn't automatically mean you have a good website. Conversely, a lower score doesn't mean the entire website must be rebuilt. Look mainly at what real users experience and which technical problems actually have impact.
Performance starts with building your website
A fast website doesn't arise only by shrinking images afterwards or turning on caching. The performance research in the Web Almanac 2024 shows, for example, that a slow LCP is not caused solely by the file size of an image. Server response time, delay in requesting resources and the time needed to render content can also play an important role.
Performance is therefore partly determined by choices made much earlier in the development process. Think of the technical architecture, frameworks used, hosting, external scripts, APIs, databases and the way content is loaded.
That is why at Ninjible we don't see speed as an optimization you add at the end. Performance is part of good web design and good software development.
Whether it concerns a website, web application, e-commerce platform or larger digital ecosystem: the less users have to wait, the better the digital experience.
