Answer · Conversion Engineering
What’s a Heatmap?
The short answer
A heatmap is a visualization showing where visitors interact with a webpage. The three types: click heatmaps (where users click), scroll heatmaps (how far down they scroll), and movement heatmaps (where their cursor moves). Useful diagnostic tool for finding friction; useless without segmentation by traffic source.
№ 01The longer answer
Heatmaps aggregate visitor behavior data and render it as colored overlays on a page screenshot. Red areas indicate high interaction; blue indicates low. They’re produced by tools like Microsoft Clarity (free), Hotjar ($39+/mo), and FullStory ($299+/mo).
Each heatmap type answers a different question. Click heatmaps surface what users think is clickable (often: non-link headlines, photos, logos). Scroll heatmaps tell you where 50% of visitors stop reading — usually 600-1000px sooner than designers expect. Movement heatmaps are mostly decorative (cursor follows eye at only ~30% correlation).
The trap: heatmaps require segmentation. A heatmap showing 40% of clicks on the header logo is meaningless if you don’t know whether those clicks came from existing customers (navigating home) or cold traffic (mistaking the logo for a link). Always segment by source before interpreting.
Heatmap reliability requires sample size. Below 1,000 sessions per segment, you’re looking at noise. Most agencies don’t mention this and report heatmaps from low-traffic pages anyway. Don’t make changes based on under-powered heatmaps.
№ 02Is Microsoft Clarity good enough?
For 90% of mid-market B2B sites, yes. It’s free, has no session cap, and the heatmap quality matches Hotjar at $39/mo. Use Clarity unless you have a specific reason to pay for Hotjar or FullStory.
№ 03How long does it take to collect heatmap data?
On a page with 1000+ monthly sessions, a reliable heatmap forms in 2-4 weeks. On a page with under 500 monthly sessions, you’ll never have enough data — don’t bother.
№ 04Can I see individual user sessions?
Yes — session replay is a related feature. All three major tools (Clarity, Hotjar, FullStory) record individual sessions you can play back. Watch with a hypothesis in mind; otherwise you’ll burn 4 hours producing zero insights.
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