How to find time elapsed from dates?

[Thomas Kakutani]

I am trying to get time to complete, so I have a "Date Added" custom field and a "Date Complete" custom field. I was looking at this web page: https://help.trello.com/article/1159-arithmetic-in-date-variables so it looks like it is doable, but none of what I have tried has worked, even if it is copy and pasted.

This is what I have right now: set custom field "# of Days" to "{{%Date Complete}} - {{%Date Add}}"

Any ideas?

[Iain Dooley]

@Thomas Kakutani I can't see any examples of using date arithmetic between 2 dates on that page, only adding or removing a number of days/weeks to/from a date.

You could do this with Trellinator:

https://gist.github.com/iaindooley/ee8450469552a37b61cee48bcaae2088

You can read more about Trellinator here:

https://community.atlassian.com/t5/Marketplace-Apps-Integrations/Introducing-Trellinator-Automate-Trello-with-Google-Apps-Script/ba-p/925271