can we create roll-up summary on formula field in salesforce?

Hi Saurabh,

Can Roll-up summary field works with Formula field? The answer is Yes and No.

Yes if the Formula field is not referring to a field from foreign object. Let me give you an example:

Project (Parent object)

Project Name (Text 50)
Due Date (Date)
Total Cost (Roll-up Summary : Sum of all child Project Items Calculated Cost)

Project Item (Child Object)

Project Item Name (Text 50)
Item Quantity (Number 18, 0)
Item Price (Currency 16, 2)
Calculated Cost (Formula = Item Quantity * Item Price)

No if the Formula field is referring to another field in a different object. Let me use the same example:

Project (Parent object) (Same as above)
Project Item (Child Object)

Project Item Name (Text 50)
Item Quantity (Number 18, 0)
Related Item (Lookup : Product)
Calculated Cost (Formula = Item Quantity * Product.Price)
Note that the Calculated Cost is now referring to a field called Price in the Product object. Because of this reason, the Roll-up Summary field (Total Cost) in the Project Object will not work anymore.

Thanks.