Margin calculation

Hello. I have a selling price of X in one cell and a cost price of Y in another cell. How do I express this as a percentage margin in an adjacent cell? Forgive such a basic question but I'm new to this.

maybe like this: =X/Y-1

As an example, I tried this. A1 is 80 and B1 is 40. In accordance with your reply, I entered the following in C1:
=(A1/B1)-1
This gave an answer of 1 which is clearly wrong. Anyone else know how I do it?

The answer is correct. 1 represents 100% which is exactly the increase of 40 to 80.

Looking at it logically - if 10% of 40 is 4, then the resultant is 44
20% of 40 is 8, the resultant sum or increase from 40 is 48
50% of 40 is 20, the resultant sum or increase from 40 is thus 40 + 20 = 60
100% of 40 is 40, the resultant sum or increase from 40 is thus 40 + 40 = 80


I use this formula all the time in my calculations ot determine % increases or decreases. To have it display as a %, just set the cell or column format to % and also set the decimal places you would like to see

Another way to do this is (End Value - Begin Value) / Begin Value x 100

Which would be (A1-B1)/A1*100

Thanks for your help. A1 is the selling price. B1 is the cost price. C1 is the margin(profit, expressed as a percentage). So if the selling price is 80 and the cost price is 40, C1 is
=(A1-B1)/A1*100.
The answer being 50%.
Have I got this now?

Ok, excuse my misinterpretation - I interpreted what you were looking for in a similar manner as HPR or Holding Period Return where holding period return/yield is calculated as the sum of all income and capital growth divided by the value at the beginning of the period being measured ie. the growth of End Value from Beginning Value