Show when task has been marked as done

[ler1995]

Hello!

I would like to create a field that shows when (date and time) a record (task) has been marked as "Done". Here is what I have so far:

How do I create a formula and/or automation to do this?

TIA!

[matthew_b]

Hi! 

You can create a "Last modified time" field and set it to trigger when the Status field is updated like this:

[ler1995]

This autopopulates yesterday's date and time into the field, and I would like for completed date and time field to be empty until "done" is the status

[Alexey_Gusev]

Hi,
You can use a formula

IF(Status='Done',LAST_MODIFIED_TIME(Status))

It's a good solution when you know that once Status is 'Done' it doesn't changed, it works instantly and uses only formula.

If somebody change the Status, output will be blank again and date of last 'Done' is lost. So if you want to save this date, you need to add automation to copy this value to another field. Or you can setup automation to put current date in some field when The record matches condition ( Status='Done' )

[matthew_b]

Ah, I see! In that case, @Alexey_Gusev 's solution below is prob best.