When working with Power BI desktop, you can define whatever date format you want to use for each date field in your model. That works well on Power BI desktop, and on the Power BI service (the browser). However, there’s one annoying case where your format is ignored, and I’m here to help with that, after a recent tough struggle. That case is when you use a date field in a slicer, shown as a slider:
The date format used in this case has nothing to do with what you may have defined as the format of the field. It will show as dd/mm/yyyy or mm/dd/yyyy and that’s usually OK, but which one will it be? dd/mm or mm/dd ?
Apparently there are a few places where you can define it, or you think you can define it. There’s the Power BI desktop language attribute, here:
There’s the Windows regional settings:
In browsers other than Microsoft’s browsers, there’s a language definition, here’s how it looks in Chrome:
And last but not least, the Power BI service language settings:
All together, this is really confusing. After a few cases I’ve encountered, I think I’m now able to determine exactly what works, and here it is.
There are two cases we need to look at: using Power BI Desktop, and using Power BI service (browser, powerbi.com).
In the Power BI desktop case, the only setting that matters is the windows regional settings. Changing the definitions under the “options” menu in Power BI desktop doesn’t change anything. I live in New Zealand, and over here the common format is dd/mm/yyyy. Setting the windows regional settings to English(New Zealand) allows that. Setting it to English(US) changes the format to mm/dd/yyyy. Note that a Power BI desktop restart is usually needed after a change.
For Power BI service (browser), it depends on which browser you are using. If you are using Microsoft browsers(Internet Explorer or Edge), the way to change your date format is the same as it is with Power BI desktop, via the Windows regional settings. If you are using a different browser, you need to do two things. The first one, is set the desired language, like English(US), or English (New Zealand) as the top option under your browser’s selected languages. It’s not enough to set it as the default, it has to be at the very top of the list (example in chrome):
Then, under the Power BI service language setting, set it to use the browsers default:
You’ll probably need to refresh your Power BI page for the changes to kick in.
I hope that helps!