What is the difference between a margin and a markup?

Margin - is the ratio of sales profit to sales price, expressed as a percentage.
For a product that costs 150zł a margin of 25% is added according to the formula:
(150*100)/(100-25)=15000/75=200zł

Mark-up - is the ratio of profit on sales to the purchase price, also expressed as a percentage.
For a product that costs 150zl a mark-up of 25% is added according to the formula:
150*1.25=187.50zł