Why investing in
Core Web Vitals pays

There are numerous insightful case studies and research materials available on web performance, psychology, and user experience. We aim to provide you with a resourceful page that empowers you to convincingly persuade stakeholders about the value of investing in Core Web Vitals.


Prioritizing pagespeed performance, a strategic investment in your future

Running a webshop is a juggling act. You're constantly bombarded with choices: new features, marketing campaigns, the latest trends, like AI. It's easy to see why improving page speed metrics like Core Web Vitals or investing in real user monitoring might fall down the list. But here's the thing: a slow website is like a leaky bucket. No matter how much you pour into marketing or features, you'll lose customers if they can't even get through the door.

Consider your eCommerce site to be a physical store. Customers are more likely to head elsewhere if they encounter long lines, cluttered aisles, or slow service. The same principle applies online. A slow website frustrates users, resulting in lost sales and missed opportunities.

Here are 10 reasons why prioritizing page speed is an investment, not just an expense.

You want more conversions

Studies consistently show a direct correlation between pagespeed and conversion rates. A faster website simply translates to more sales. Just a A 0.1-second increase in loading time results in:

  • + 8.4% conversions and + 9.2% on the average shopping basket in the retail market;

  • +10.1% conversions and +1.9% on the average basket in the travel market;

  • +8.6% of page views per session in the luxury sector

  • -8.3% bounce rate on forms in general in the retail market.

Milliseconds make Millions

We’ve actually collected a wide set of research for you, just on this subject. From Vodafone to Redbus, continually there’s a strong correlation between a faster website and more sales. Read all of our Core Web Vitals case studies.

You want market growth

A speedy website opens doors to a wider audience to buy from you. Did you know that audience conditions can greatly impact how they experience your site? You might be browsing your site with a €1500,- smartphone, on a 5G connection, but the rest of the world might not.

This matters, because internet speed directly impacts how fast a browser can download your website and show it to the user. Both Largest Contentful Paint (LCP) and Interaction to Next Paint Core (INP) Core Web Vitals metrics are largely impacted by who your audiences are and how they experience your site.

  • People who have slow internet can download your site slower, between 2G and 3G we see much slower page loading times. Around 4G + 5G the impact gets less substantial. This impacts your LCP.

  • People who have less RAM on their phone, and therefore likely have less CPU power have a lot more issues with INP, because the browser isn’t fast enough to respond to their actions, causing a delay.

interaction to next paint device memory
You can see that INP is much worse for the low-end phone (2048 MiB) than for the high-end phone (8192 MiB).
lcp internet speed
LCP by internet speed measured in RUMvision, the slower the internet connection, the worse the LCP.

There are 2 growth possibilities here.

  1. More global sales: internet speed is really fast here in the Netherlands (where RUMvision is from), and 4G+ is pretty much the norm. But in other parts of the world, there is a lot more 3G mobile internet. Don’t think it’s just outside of the EU, we already see a large difference in Germany and Spain for instance. If you really want to deep dive into this, I recommend reading The Performance Inequality Gap, 2024, which will explain to you how having a good phone greatly helps performance.

  2. Boosted revenue from domestic customers, including those with slower connections or phones. Think about it: Would someone on the train with a slow internet connection never want to buy something from you? Or someone with a low- or mid-range phone? Or do you want to ensure that they also have a positive experience?

Improving performance and focusing on Core Web Vitals would help them both. Using real user monitoring would allow you to visualize this.

You want people to return to your shop

If you had a bad experience in an actual store, would you want to return to buy more? Probably not, or it should be a really good deal. The same is true for your online visitors; they remember their experience when they decide to return. Good experience? I would love to shop again or subscribe to your newsletter. This helps organic growth.

Was it a bad experience? No thanks; I'll go to your competitor or a marketplace such as Amazon.

62 % visitors will not return after bad mobile experience

Think With Google

You want to reduce bounce rate

This is an extension of the previous point, because why would you even wait for a couple of seconds for a page to load? First impressions matter, and a page taking forever to load or staying white for a long time requires patience you can’t expect everyone to have.

Research from Google proves that 8.1% of bounce gets reduced by improving the LCP. That's 8.1% of visitors that you lost!

bounce rate pagespeed


You care about your brand-image

You put a lot of effort into building your brand. Whether it's a luxury brand or all about putting the customer first, you want people to have a certain feeling when they think of it, both online and offline. You want your website to feel trustworthy, pleasant, all-the-while while staying unique!

However, if your website is slow to respond (INP), moves around (CLS), or takes forever to load (LCP), it can harm your brand image. Worse, what if people dislike the experience so much they begin to tell others about it?

Luckily, the Core Web Vitals help you determine if there are issues for your real users. Real user monitoring, like RUMvision can help you gain insights even further. For instance, deepdive on what exact page and element users were actually experiencing a layout shift. But this is also where knowing your real audiences comes in handy, as well as knowing what to optimize. For instance, Google Lighthouse often suggests compressing images. We say, it depends.

As an example, a luxury brand may not benefit from severely compressing their images, as the quality will inevitably decline. A high-quality image may be more beneficial to your brand's image for suits priced at €500 or more than one that loads rapidly.

Knowing the average internet speed that your site's visitors use might help you make an informed decision about the image quality, which is crucial since there is a delicate balance to maintain between performance and brand image. Because of its superior quality and the ease with which it will persuade your target audience to make a purchase, I would consistently choose the 125KB image if I knew that the vast majority of my audience had internet speeds of 6MBps or higher.

Note that this is not an invitation to upload 10MB+ images 😛

resize images core web vitals


Sustainability matters to you and your brand

This might not actually be something you've ever thought about, but your website uses electricity and emits carbon emissions as well, through its data centers and taking battery life of phones. And this can be quite a lot! It’s estimated that internet usage accounts for 3.7% of global CO2 emissions, and that will double in 2025! In fact, it’s more than aviation.

If you want to find out an estimate about how much carbon your website emits, use the website carbon calculator.The key takeaway here is that improving web performance makes your site more sustainable. More details on how? Read the Web Sustainability Guidelines (WSG) 1.0

Investing in web performance can help you reduce your environmental impact because faster websites use less energy and transfer less data. This not only aligns with responsible business practices, but it also appeals to environmentally conscious consumers and better fits your company's image. A win-win-win.

You want to keep your server load stable

A lower page load means you can also have more visitors on your website at the same time. Practical if you’re expecting a huge rush, for instance with a Black Friday Sale. A fast website can handle more traffic without straining your server resources. This translates to improved scalability, allowing you to accommodate growth without worrying about infrastructure bottlenecks.

You want a lower PPC and better CTR for your ads

Why spend heavily on attracting visitors via SEA if your website itself drives them away? Optimizing page speed allows you to convert the traffic you already pay for. Because not only does it reduce bounce - additional fun fact- an ad by itself will cause a delay because it’s an extra redirect to your site.

Good Core Web Vitals can contribute to lower PPC. In Google Ads, the quality score (experience on the landing page) can contribute to your position and thus directly affects the bid to achieve a certain position. We have seen, in real-life cases, that improving the technical experience has led to a reduction in CPC of up to 20-25%. You could also consider the fact that better page speed benefits the automated bidding strategy as a nice bonus.

It’s a win-win you can easily visualize with using RUMvision, we’ve actually written a whole use-case for this: https://www.rumvision.com/use-cases/making-sure-paid-traffic-has-the-best-page-speed-possible/

You care about Developer happiness

You might not believe it, but optimizing for speed and improving UX can be fun for developers to work on. Because as it turns out, developers are just like people, they want people to be happy with their work!

However, when developers are unable to reproduce an issue, it can be frustrating. It is safe to say that few things annoy a developer more than hearing someone exclaim, "The website is slow!" without providing any further explanation or insight into the matter.

This is why it's satisfying for frontend developers to see how real users' performance changes quickly after a release through real user monitoring tools like RUMvision. Changes in performance are easily visualized, and a trend line makes it interesting to see progress. Deep diving into real user data, as well as third-party impact, makes data-driven decisions much easier and saves a lot of time debugging issues.

Giving developers more time to code and fix Core Web Vitals issues. A happy circle of life, really.

You want to improve SEO

Google places a high value on a positive page experience. So much that the Core Web Vitals are a free publicly available dataset provided by Google.

Google themselves say that it is critical for site owners to have good Core Web Vitals if they want to perform well in Search (as well as provide a good user experience in general).

And while true Google ranking factors are notoriously hard to figure out, the fact they put such a focus on it for free, is vitally important to take into account. https://developers.google.com/search/docs/appearance/page-experience

For more info on this subject: https://www.rumvision.com/blog/impact-core-web-vitals-seo/


Don't waste time and effort on optimizations that miss the mark. Invest in real user monitoring (RUM) tools like RUMvision to gain valuable insights into your website's performance. By focusing on page speed and Core Web Vitals, you're unlocking a wealth of benefits that contribute to the long-term success of your webshop.

Remember, a fast and efficient website is an investment, not an expense. It's the foundation for a thriving online business that keeps customers happy, coming back for more.