Definition
Email heatmap analysis uses aggregated engagement data to create visual representations of how subscribers interact with email content. Heatmaps reveal which areas of an email attract the most attention, which elements are being clicked, and how far subscribers scroll before losing interest. This data-driven approach to email design optimisation replaces guesswork with empirical evidence about what works for your specific audience.
Click heatmaps are the most common type of email heatmap. They overlay click data onto the email design, using colour intensity to show where clicks are concentrated. Hot spots in bright red indicate areas with high click density, while cool areas in blue indicate areas with low click activity. Click heatmaps immediately reveal whether subscribers are clicking where you expect them to click, or whether attention is being drawn to unintended elements such as navigation links or secondary CTAs. They also reveal dead zones where subscribers are not clicking despite the presence of clickable elements.
Scroll depth heatmaps measure how far subscribers scroll through an email before stopping. This data is collected by tracking which content regions are visible when a subscriber has the email open, or by proxy methods that measure the time between email open and first click combined with content position. Scroll depth heatmaps answer critical layout questions such as whether subscribers are seeing content below the fold, whether the email is too long, and whether key messages and CTAs should be moved higher in the layout.
Best Practices
- Generate click heatmaps for every campaign and review before the next send: Make click heatmap analysis a standard part of your campaign review process. Compare click distribution against your design intent. If subscribers are clicking unintended elements or ignoring primary CTAs, adjust the design before the next similar campaign.
- Combine click, scroll, and attention heatmap data for comprehensive understanding: Click heatmaps show what people click but not what they see. Scroll heatmaps show what people see but not what they notice. Attention heatmaps estimate visual focus based on mouse movement and scroll patterns. Combining all three data types provides the most complete picture of subscriber engagement behaviour.
- Segment heatmap analysis by subscriber group to identify behavioural differences: High-value subscribers may engage with email differently than new subscribers or lapsed subscribers. Generate separate heatmaps for different subscriber segments and compare the engagement patterns. Segment-specific insights enable targeted layout optimisation for each audience.
- Use heatmap insights to inform template redesign rather than reactive adjustments: Collect heatmap data over 4-8 weeks across multiple campaigns before making template changes. Look for consistent patterns rather than campaign-specific anomalies. Use the aggregated data to inform your next template redesign cycle, positioning key elements in proven high-engagement zones.
- Install heatmap tracking on a sample of your subscriber list rather than full volume: Full-list heatmap tracking generates large data volumes that are expensive to store and process. Track heatmap data from a representative 10-20% sample of your list, ensuring the sample is statistically representative of your full subscriber base. Sample sizes of 5,000-10,000 engaged subscribers provide reliable heatmap data.
Related Glossary Terms
A/B Testing
A/B testing in email marketing is the practice of sending two variations of an email to a small sample of your list to determine which version performs better before sending the winner to the remaining subscribers.
Above the Fold in Email
Above the fold in email refers to the content visible to a recipient before they scroll, a critical area for first impressions and primary calls to action.
Accessible CTA (Email)
An accessible CTA is a button or link coded with sufficient colour contrast, visible focus states, descriptive screen-reader text, and a minimum touch target of 44×44 pixels.
Adaptive Design
Adaptive design in email uses predefined layouts that adjust to specific device or client widths, rather than fluidly resizing to every possible screen.
AI-Generated Content in Email
AI-generated content in email is copy, images, code or subject lines produced by artificial intelligence tools to speed up campaign production and testing.
Alt Text
Alt text is the written alternative to an image in an email, displayed when images are blocked, slow to load, or consumed by screen readers.
Frequently Asked Questions
Click heatmapping records the pixel coordinates of every click within an email and aggregates them across all recipients. The aggregated data is overlaid on the email design, with colour intensity representing click density. Most ESP analytics platforms offer built-in click heatmapping, and third-party tools provide more detailed visualisation and segmentation options.
A scroll depth heatmap shows what percentage of subscribers scroll to each point in your email. It is displayed as a gradient overlay on the email layout, showing where subscriber drop-off occurs. For example, a scroll depth heatmap might show that 80% of subscribers see content in the top third of the email, but only 30% scroll to the bottom, informing decisions about content placement and email length.
Attention heatmaps use mouse movement patterns, scroll behaviour, and time-on-element data to estimate where subscribers are visually focused, even if they do not click. Click heatmaps only show where clicks occur. Attention heatmaps are valuable because many subscribers read email content without clicking, and understanding what they read helps optimise content placement and messaging hierarchy.
Major ESPs including Salesforce Marketing Cloud, Braze, and Mailchimp offer built-in click heatmap functionality. Third-party tools such as Email on Acid, Litmus, and Sinch Mailjet provide more advanced heatmapping including scroll depth and attention heatmaps. Dedicated email analytics platforms offer the most sophisticated heatmapping with segmentation and trend analysis capabilities.
Reliable heatmap data typically requires a minimum of 500-1,000 engaged subscribers who open and interact with the email. For segmented heatmaps, each segment needs at least 500 engaged subscribers. Smaller samples produce noise that can be mistaken for patterns. Collect data across multiple campaigns to validate that heatmap patterns are consistent rather than campaign-specific.