How Do Popups Affect Your Website Speed? A Comprehensive Popup Speed Test Study

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If you’re running an ecommerce website, page loading speed is everything. We all know the frustration of waiting for a slow website to load. Adding popups—if they’re not optimized—can slow things down even more.

But how much of an impact do popups really have on your website speed?

To find the answer to this question, we took a close look at the speed performance of some of the most popular popup software on the market. In this article, we’ll share the results, showing you which tools are speeding things up (or slowing them down).

Let’s jump in!

Why does page speed matter when choosing a popup tool?

First off, let’s address why website speed matters.

A slow website is like a leaky bucket. Every extra second a visitor waits for your landing page to load increases the likelihood they’ll bounce and visit a competitor instead.

When popups are involved, they’re not just affecting their own load time—they can drag down your entire website speed if you’re not using the right tool.

Here’s why popups can slow down your site:

  • Extra resources: Pop-ups rely on scripts and stylesheets, which means additional files for your browser to load. The more files, the slower the page load time.
  • Content blocking: A poorly optimized popup can block other important content from loading, leaving your visitors stuck in limbo and frustrated.
  • Increased server requests: Each popup adds to the number of requests sent to the server, leading to slower response times, especially during high-traffic periods.

If your popup tool is bogging down your site, it’s hurting both your conversions and your SEO. That’s why choosing a fast, lightweight popup solution is crucial for keeping visitors happy and your page’s speed lightning-quick.

The methodology: how we tested

To get a true sense of how popups impact load times, we selected the following tools for a comprehensive site speed test:

  • OptiMonk
  • Justuno
  • VWO
  • Ecomsend
  • Klaviyo
  • Privy
  • Sleeknote
  • Personizely

Note: Some tools were excluded because they don’t display popups on speed measurement platforms, making performance tracking impossible.

We used GTMetrix, a leading website performance testing tool, to evaluate these popup platforms across both desktop and mobile devices.

GTMetrix site speed tool

Testing was conducted in five regions to account for global performance variations:

  • Vancouver, Canada
  • San Francisco, USA
  • Frankfurt, Germany
  • Singapore
  • Sydney, Australia

It’s worth noting that we tested popups without images to focus solely on the tools themselves. Images can significantly skew results by affecting the LCP (Largest Contentful Paint), a metric that doesn’t fully capture the performance impact of popups on loading times.

Key metrics measured

GTMetrix measures many metrics, but it aggregates the results of these metrics into easy-to-understand insights that are crucial for optimizing page speeds:

  • Grade: A letter grade from “A” (best) to “F” (worst), calculated based on performance and structure.
  • Performance: A score from 1 to 100, with higher numbers indicating faster load times and better performance.

We averaged the results across desktop and mobile to give a clearer picture of overall performance. While GTMetrix measures many aspects of website efficiency, not all of them are relevant for popups, so we focused on the most pertinent data.

The results

Alright, now that we’ve covered the methodology, it’s time to break down how each popup tool fared in our page speed test.

Desktop loading speed performance

The popups we used for our page speed test followed a simple, standardized design to ensure consistent results. None of the popups included images, and each popup featured four key elements:

  • A headline
  • A short description providing context or additional information
  • An input field used for email capture
  • A call-to-action button

This clean, minimalist setup kept things consistent across all tools, letting us measure how efficiently the core components of the popup loaded.

Take a look at the popups we used here:

Pop-ups used in the page speed test

Across all tests, OptiMonk consistently outperformed the competition, earning top marks in both Grades and Performance. Other notable performers included VWO and Klaviyo, which also scored highly in several regions.

In terms of performance score, OptiMonk was leading the way, with VWO coming in second and Ecomsend coming in third:

How do popups affect your page speed on desktop? Performance data

OptiMonk earned an “A” in all but one region. Other popup tools achieved a more mixed result:

How do popups affect your page speed on desktop? Grades

Here, you can see the raw page speed results for each region and test:

Vancouver, Canada

San Francisco, USA

Frankfurt, Germany

Singapore

Sydney, Australia

Mobile performance loading speed

Now, let’s take a look at the mobile results.

Again, here are the popups that appeared for our page speed tests:

Pop-ups used in the page speed test

On mobile, the performance was similar, with OptiMonk taking the top spot across the board. Mobile performance is often even more crucial because mobile visitors are typically less patient with slow load times. On mobile, VWO and Klaviyo were again close competitors, only falling short by a few points in some regions.

OptiMonk’s flawless performance on mobile devices reinforces its reliability for websites looking to maintain fast loading times, regardless of device or region.

Here, you can see the raw results for each region and test:

Vancouver, Kanada

San Francisco, USA

Frankfurt, Germany

Singapore

Sydney, Australia

Conclusion

Across all regions and devices, OptiMonk was the clear winner. Its use of CDN technology ensures popups are delivered quickly, no matter where your visitors are located. For ecommerce businesses or anyone relying on popups to drive conversions, OptiMonk is the tool to beat.

While other tools like VWO and Klaviyo offer solid performance, they can’t quite match the load speed and consistency of OptiMonk. For anyone prioritizing a fast, smooth user experience—especially in a world where every millisecond counts—OptiMonk should be at the top of your list.

Whether you’re running an international ecommerce store or a local site, choosing the right popup tool can make all the difference in maintaining fast load times while maximizing conversions.

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