How do I update the Opportunity ‘Amount’ field with a formula that sums custom Opportunity Product fields?

First off – the documentation on the SFDC site is incorrect on this issue. The question keeps getting asked, people get referred to this link, and then they soon write back saying that it DOES NOT WORK.

In short, since the Amount field on Opps only calculates Sales Price, Quantity and Discount, the taxes (or any custom $ field) do not get added. Some of our products are fee -and are not taxed.

The method of using a WFR to update the Sales Price (as in Total Tax Amount__c) so as to update the Total Sales, to in turn update the Opp Amount figure does not in fact update the Sales Price.

Result: Our quotes have the wrong Amount.


The TotalPrice (UnitPrice X Quantity) across all Opportunity line items rolls up to the Opportunity Amount. If you wanted to affect the TotalPrice on the OLI, you could update the UnitPrice with the optional extras so that they are factored into the TotalPrice. This would then roll up to the Opportunity Amount.

In summary, custom fields cannot be made to roll up directly, however you can use them to affect the UnitPrice which multiplied by Quantity rolls up.

Hopefully that makes sense.

Source : Link , Question Author : Bart__c , Answer Author : techtrekker

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