profit margin 
noun
The amount by which revenue from sales exceeds costs in a business: we have a gross profit margin of 80 per cent current levels of interest can erode profit margins...
- Go to the income statement again to find the gross profit margin, which is revenue less cost of revenue.
- That's because falling unit costs increase the profit margin on each good or service sold.
- Sales of gifts and entertainment services generally have a higher profit margin than sales of airline tickets.