Divide the selling price by the purchase price (or cost), from the result of the subtract unit and multiply the resulting number by one hundred - is a simple algorithm to calculate the fee in percentage.
Use the calculator for the practical calculation of margins. If you prefer to use a computer, then you can use the built-in Windows calculator. The easiest way to start is to press the key combination WIN + R, type the command calc and press Enter. But you can do it through the main menu. To do this, click "start" button, select "Programs", go to "Standard". In it, expand the section "Service" and select "Calculator". The calculator interface is a little different from the usual, so the calculations will not cause difficulties.
Take, for example, Microsoft Office Excel if you need to make such calculation constantly or for a large number of goods. In this tabular editor you can create the formula once, save and then change the value of the purchase and retail prices and immediately see the result without repeating each time manual calculations or enter formulas. If you decide to use this method - start Excel and the program will automatically create an empty table to work.
Enter in the first cell of the retail price and click the right arrow to move to the next cell of the row. Do not enter in the purchase price and click the right arrow. In the third cell I put the formula to calculate the margin in percentage.
Type an equal sign - a tabular editor believes the formula contents of a cell if it begins with this sign. Then click the first cell (the retail price), press the slash ("slash") and click the second cell (the purchase price). Enter a minus sign and unit. After this press Enter and enter the formula will be finished.
Click the cell with the formula, right-click and select the context menu "Format cells". In the list of "Numeric formats" in the opened window, select "Percentage" and specify how many decimal places to display tabular editor in the result set. Then click the "OK" button. The creation of the simplest signs to calculate margin in percent to be completed. If necessary, you can copy the cell with the formula and paste it in any number of rows and then fill-line retail and purchasing prices of other goods. To avoid confusion, it is possible to write in the fourth cell of the product names.