What is difference between Mark up and Margin?

Margin = (Sale Price - Cost)/Sale Price

So lets say you are a distributor and buy soap for 1 Dollar and sell it for 2 Dollar your margin will be (2-1)/2 so 0.5 or 50 Percent gross margin.

Your mark up will be how much you raise the price, so in the example above 100% from 1 to 2.