Smart Field Question

[Ken Murray]

Hey guys new to Trello 

Trying to build a manufacturing schedule 

I have the HOURS on the card - basic field 

I have the DUE DATE on the card - basic field

i want to subtract HOURS from Due Date to create a "Start Date" 

any advice for what powerups i need or how to go about this? 

[milynnus]

@Ken Murray 

You can do it by using a date CF to set the start date but it cannot do hours.