Question

"Can I automate this in Notion? I'd like to create two databases: one for habits and one for days. The habits database would show which days a habit was completed and its overall completion rate. The days database would show which habits were completed on a specific day and the overall completion rate for that day. Can these databases be linked so that when I check a habit for a specific day, it automatically updates in both databases? Or is there a better way to do this?"

Answer 1

I believe this template is similar to your use-case.

https://makedigitalspace.notion.site/Goals-and-Habits-Tracker-1747189becaa80bb8a40c2264eaace96

What you're trying to achieve can be done using relation property and formula.

If you're interested to build it yourself then here's a brief explanation of it:
https://www.notion.com/help/relations-and-rollups

a video explanation of how you can use formula to pull information:
https://youtu.be/PJzJWz5ARa0