How can I convert 2020-12-14T18:24:27.000Z to 12/14/2020 in Google Sheets?
The Format > Number > Date command does not change the timestamp to a date.
The conversion can occcur in-place or a separate column.
You can extract the date portion of the timestamp using MID() then use DATEVALUE() to convert it to date format.
=DATEVALUE(MID(A1,1,10))
Then use Format > Number > Date command.

References:
MID()
DATEVALUE()
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With