Google sheets spreadsheet will not format date correctly

Question

I have a Google spreadsheet with a date column formatted to dd mmm yyyy. Many of the dates are formatted this way, but some cells will not format this way, and no matter what I select under "Format", "Number", I cannot get these cells to change at all. It seems to remain the text that I entered, but I want it to switch to my preferred format selection.

Answer 1

If the cell values don't change the way that they are displayed then those values are text, not dates.

This occurs because Google Sheets internally manage dates and duration as numbers, to be more precise as serialized numbers.

This commonly occurs on ambiguos "dates", those that use 2 digits for months instead of three letters and that have day equal or greater than 13.

There are several workarounds, one is to split the "date" parts and use date(year, month, day) function,