I need to create rollup summary type of field on Object A by summing specific field from Object B where Object A is master, Object B is child and there exists a lookup relationship between the two. What is the best approach to achieve this. EDIT: I cannot change the type of relationship from lookup to Master Detail.

  • 1
    You can't do a roll-up summary with a lookup field, so you'll either need to convert it to a master-detail, or write a trigger. Not sure if the new process builder can do this or not.
    – Nick C
    Commented Feb 15, 2015 at 12:49

1 Answer 1


You have a few options here. As @Nick Cook mentioned in a comment, you could change the relationship to Master-Detail but this could cause a lot of work as all the reports on that field would have to be recreated.

If you decide you want to leave it as a lookup relationship, you have two basic options to create the rollup yourself. You can try to find an app on the app exchange that does this for you or you can try to build it yourself via Apex.

If you want to find an app on the app exchange, I would recommend the rollup helper (**** I have no personal affiliation or interest in this product, just one that I have used in the past and works well). The rollup helper can be found here.

If you want to go the route of coding, there are a few nifty packages out there that I would look into

Anthony Victorio wrote a nice utility for creating your own rollups. Take a look here.

Andy Fawcett also wrote a utility for this as well that you can find here

Hope this helps.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .