Heatmap
A heatmap is a data visualization that uses a color spectrum to show how users interact with a web page: where they click, how far they scroll, and what they look at. Warm colors (red, orange) mark areas of high activity, while cool colors (blue, gray) mark areas with little or no interaction. The three main types are click maps, scroll maps, and eye-tracking heatmaps.
Heatmaps turn abstract user behavior data into an intuitive visual basis for decisions. Their value is backed by extensive research:
- Users don’t read, they scan: across three eye-tracking studies (500+ participants, 750+ hours of testing, 13 years of research), Nielsen Norman Group showed that people don’t read web content word by word but scan it in predictable patterns (NNGroup – How People Read Online, 2020)
- Half the page goes unseen: according to the Contentsquare Digital Experience Benchmarks 2025 (an analysis of 90 billion sessions on 6,000 websites), scroll depth hovers around 50%, so on average half of a page’s content is never seen (Contentsquare – Digital Experience Benchmarks, 2025)
- Strong visual signifiers improve efficiency: an NNGroup eye-tracking experiment with 71 participants showed that pages with strong visual signifiers guide users to their goal much better: 86% of participants focused their attention correctly, compared with 50% for weak signifiers (NNGroup – Heatmap Visualizations from Signifier Experiment)
- Real impact on conversions: the online store WallMonkeys analyzed click maps and scroll maps, identified an underperforming slider, and replaced it with a search bar, which led to a 550% increase in conversion rate (Crazy Egg – WallMonkeys Case Study)
- Eye tracking reveals what clicks don’t: in its e-commerce eye-tracking research (32 participants, Tobii eye tracker), Baymard Institute found that eye tracking uncovers issues that click maps alone miss (Baymard Institute – Research Methodology)
FAQ
Which type of heatmap should I use?
It depends on your goal. Click maps are ideal for evaluating CTAs and navigation. Scroll maps show how much of your content is actually seen. Contentsquare data from 90 billion sessions shows that on average only half of a page gets seen. Eye-tracking heatmaps are the most accurate but require specialized equipment.
How much data do I need for a reliable heatmap?
For click maps and scroll maps, the more visitors, the more reliable the picture. Tools like Hotjar (1.1+ million websites) or Microsoft Clarity (100+ million users per month) collect data automatically. For eye-tracking studies, NNGroup recommends about 39 participants per heatmap.
Are there free heatmap tools?
Yes. Microsoft Clarity offers click maps, scroll maps, and session recordings completely free, with no data volume limits. Paid tools include Hotjar and Crazy Egg, which also offer A/B testing based directly on heatmap data.
Sources:
- NNGroup – How People Read Online (2020) – 3 eye-tracking studies, 500+ participants, 750+ hours of testing
- NNGroup – Heatmap Visualizations from Signifier Experiment – quantitative experiment, 71 participants
- Contentsquare – Digital Experience Benchmarks 2025 – analysis of 90 billion sessions, 6,000 websites
- Baymard Institute – Research Methodology – 18,000+ user tests, eye tracking
- Crazy Egg – WallMonkeys Case Study – 550% increase in conversions
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