Calculating Margin on an Opportunity

Problem

There is no out-of-the-box way or field in Salesforce that calculates margin on a sales deal.

Solution

Create a total cost field on the opportunity record that is a currency field. Add a product cost field to your products. Rollup your Opportunities Line Items and reference the source field for the related product's cost to get the total product cost across all line items. Then create a formula field that calculates margin between selling pricing and product cost.