Question 1

What format does the CSV data need to be?

Accepted Answer

Each line should contain a date in YYYY-MM-DD format followed by a comma and a numeric value, for example: 2024-03-15,7. The tool auto-detects the year range from your data.

Question 2

What is a calendar heatmap?

Accepted Answer

A calendar heatmap shows data intensity across days of a year using color shading. Darker cells indicate higher values. It was popularized by GitHub's contribution graph and is commonly used for habits, analytics, and activity tracking.

Question 3

Can I use it for multiple years of data?

Accepted Answer

Yes. The tool renders one calendar grid per year found in your data. Scroll down if your data spans multiple years.

Question 4

How do I download the heatmap?

Accepted Answer

Click Download PNG to save the rendered canvas as an image file. The download includes the full calendar grid for all years in your data.

Question 5

Is there a limit on how much data I can paste?

Accepted Answer

No hard limit. Rendering is done client-side on a canvas element. Large datasets with several years of daily data will still render quickly.

Calendar Heatmap Generator

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