Enter the list rate, the units you pay for, the extra units given under the scheme (the 10 + 1 style) and any cash discount. The tool spreads what you pay across every unit received to give an effective cost per unit and an effective discount, and shows your margin if you add a selling price.
Calculations run in your browser. This tool does not send the values you enter to a server.
The net payable (units bought times the rate, less the discount) divided by all units received, including the extra scheme units.
Only after you enter a selling price above zero. It shows the margin per unit, the margin percentage and the total profit if all units sell.