UX Score: the new standard for digital performance

Online shoppers expect more than competitive prices and wide product selection. Speed, stability, and ease of use are equally critical to their experience and ultimately, your conversion rates. The UX Score makes this tangible and comparable: an objective measure that captures the digital experience in a single number from 0 to 100.

What is UX Score?

UX Score is a composite index from 0 to 100 that measures how smoothly and pleasantly a website performs in practice. This isn't about synthetic lab tests-it's about real user experiences collected anonymously at an aggregate level through Google's Chrome User Experience Report (CrUX).

This data is publicly accessible via Google BigQuery, the CrUX API, and various online tools. We use it to assess website performance on the most critical success factors: loading speed, visual stability, and interaction responsiveness.

Featured in Twinkle100

The UX Score methodology is featured in Twinkle100, Twinkle Magazine's annual ranking of the top 100 e-commerce sites in the Netherlands. This ranking is produced in collaboration with the Centre for Market Insights (CMI) at Hogeschool van Amsterdam and uses real user data from the Chrome User Experience Report (CrUX).

The Twinkle100 analysis goes beyond simple rankings to include trend analysis, quality marks, payment methods, website traffic, and performance metrics. This comprehensive approach helps organisations like Bol.com, Coolblue, and Albert Heijn understand how their digital performance compares across the industry.

Read our Twinkle100 case study to learn how we analyse performance data for the top e-commerce sites in the Netherlands.

How UX Score is calculated

Each metric receives a score from 0 to 100, depending on how well a site performs. We use Google's established thresholds:

• Good means the experience meets the highest standard
• Needs Improvement means the experience is acceptable but could be better
• Poor means the experience demonstrably leads to frustration and abandonment

These scores combine into one overall picture: the UX Score.

Total: 100 points maximum

Core Web Vitals: where we focus most

The three Core Web Vitals are central to the UX Score, each worth 25 points:

Largest Contentful Paint (LCP) - 25 points

Measures how quickly the main content becomes visible. A high LCP often means customers abandon before they've seen anything. Target: under 2.5 seconds.

Cumulative Layout Shift (CLS) - 25 points

Measures how stable the page remains during loading. Poor CLS causes frustration when buttons jump at the moment of clicking. Target: under 0.1.

Interaction to Next Paint (INP) - 25 points

Measures how quickly the site responds to interactions (clicks, taps, and keyboard input). A slow INP makes the site feel unreliable or unprofessional. Target: under 200 milliseconds.

These metrics were chosen by Google because they correlate most strongly with customer satisfaction, bounce rate, and conversion. This aligns with the most modern standards from Google.

Supporting metrics

Beyond Core Web Vitals, supporting factors contribute to a complete picture:

Time to First Byte (TTFB) - 10 points

Measures how quickly the server responds. Target: under 800 milliseconds.

First Contentful Paint (FCP) - 15 points

Measures how quickly the first visible content appears. Target: under 1.8 seconds.

By combining both Core Web Vitals and supporting Web Vitals, we create a reliable and complete picture of digital performance, covering the entire journey from loading to interaction.

What does a score of 100 mean?

A UX Score of 100 represents the highest level of digital performance. The site is exceptionally fast, stable, and responds instantly to interactions:

• The server responds immediately (TTFB)
• First content appears without delay (FCP)
• Main content is quickly visible (LCP)
• The page remains stable without unexpected shifts (CLS)
• The site feels smooth with every click or touch (INP)

Leading e-commerce sites increasingly achieve this level, demonstrating that an excellent user experience is achievable when consistently invested in.

Why this score matters for your organisation

The UX Score isn't a technical KPI for developers-it's a strategic indicator for everyone responsible for revenue, brand, and customer experience.

A high score means:

• Customers move through your site without friction
• They see products faster and click with confidence
• No disruptive interruptions in their journey
• This translates directly to higher conversions, lower bounce rates, and more returning customers

A low score indicates:

• Moments in the customer journey that cause frustration
• Slow server response causing sluggish page starts
• Product images taking seconds to appear
• Unstable layouts causing misclicks or lost content
• These aren't minor irritations-they're moments where customers abandon and revenue leaks away

Three concrete benefits for organisations:

1. Management Information: One number shows how your site's digital experience compares to the market
2. Team Focus: Makes clear where investments in IT, marketing, or design yield the most return
3. Business Case Support: Performance improvements are no longer just technical optimisations-they're key drivers of growth and customer satisfaction

The UX Score makes it possible to translate speed, stability, and responsiveness into language everyone understands: the language of customer experience and business results.

Conclusion

Retailers compete on product, price, and brand-but user experience is becoming increasingly important. The UX Score makes this visible and measurable.

In the Twinkle100 ranking, you'll see not only which companies achieve the highest revenue, but also which organizations provide their customers with the best digital experience. In an era where consumers abandon quickly at the slightest digital friction, this is valuable information for every digital leader.

UX Score vs other metrics

How to measure your UX Score

Want to know your current UX Score? Use our free benchmark tool to get an instant analysis of your website's performance.

Ongoing monitoring options

For continuous tracking of your UX Score over time, consider these approaches:

1. Real User Monitoring (RUM) and Observability Tools

Use a RUM or frontend observability platform to collect real user data:

• DebugBear - Web performance monitoring with Core Web Vitals tracking
• SpeedCurve - RUM and synthetic monitoring
• Honeycomb - Frontend observability with detailed trace analysis
• Grafana Faro - Open-source frontend observability

2. Google Analytics 4 + Web Vitals

Combine GA4 with the web-vitals library to track Core Web Vitals alongside behavior metrics:

• Install web-vitals package: npm install web-vitals
• Send Core Web Vitals to GA4 as custom events
• Create dashboards correlating performance with conversions

3. Custom Implementation

Build your own tracking using the Web Vitals JavaScript library and your analytics platform.

Improving your UX Score

Follow this prioritized approach to boost your UX Score:

Step 1: identify the weakest component

Look at your UX Score breakdown. Which component is lowest?

• Low LCP Score? → Focus on Largest Contentful Paint optimisation
• Low INP Score? → Focus on Interaction to Next Paint improvements
• Low CLS Score? → Focus on Cumulative Layout Shift fixes

Step 2: quick wins

Start with these high-impact, low-effort optimisations:

• Images: Use modern formats (WebP, AVIF), lazy loading, and responsive images
• Fonts: Use font-display: swap and preload critical fonts
• JavaScript: Defer non-critical scripts and split large bundles
• Layout Shifts: Set width/height on images and reserve space for ads

Step 3: measure impact

After each optimisation:

• Wait 7-14 days for sufficient RUM data
• Compare before/after UX Score
• Track impact on business metrics (conversion rate, revenue)
• Iterate on the optimisations with the biggest ROI

Get started with UX Score

Ready to measure and improve your UX Score? Here's how to get started:

1. Set up Real User Monitoring - Install a frontend observability tool or the web-vitals library
2. Establish your baseline - Collect 2-4 weeks of data to understand current performance
3. Identify opportunities - Find which component (LCP, INP, CLS) has the most room for improvement
4. Implement optimisations - Start with quick wins, then tackle larger issues
5. Measure business impact - Track how UX Score improvements correlate with conversions

Need help improving your UX Score? Contact our web performance consultants for a free audit and optimisation roadmap.

Related Resources

• Core Web Vitals Guide - Deep dive into LCP, INP, and CLS
• Frontend Observability Guide - Learn how to instrument and monitor real user performance
• Optimize Largest Contentful Paint (LCP)
• Improve Interaction to Next Paint (INP)
• Fix Cumulative Layout Shift (CLS)