A question that, when googled, will display pages of blogs and opinions. According to Microsoft there are at least 5 different options for creating a Power BI calendar, with pros and cons for each. Which one you use depends on what the table is for, your programming experience, what data you have access to and your own personal preference (or the preference of the person you’re asking for advice!).
The flow diagram below aims to help you decide which solution is best for your particular need. It is not meant to be a definitive answer but aims to help you in your decision process, especially if you’re new to Power BI.
I’ve create a step by step guide for each of the DAX, M and Excel date table solutions, a link to each blog can be found here

If you’re still unsure why you need a calendar table check out this blog first: What is a calendar table and why should I create one in my Power BI project?
- How to create date table in Power BI with a ready-made Excel file
- How to create a DAX date table
- How to create a Power Query M date table
Cover photo by Brooke Lark on Unsplash