Updated
The formulas
profit = price - cost
margin = profit / price
markup = profit / costA worked example
A product costs 60 to make and sells for 100. The profit is 40.
The margin is 40 divided by 100, so 40 percent. The markup is 40 divided by 60, so 66.7 percent. It is the same sale and the same profit, described two ways.
Why it matters
If you want a 40 percent margin and add 40 percent to the cost, you end up with a 60 cost and an 84 price. That is a margin of only 28.6 percent.
Markup is always the bigger number for the same sale. Know which one a supplier, a client or your accountant means.
Convert between them
Use the decimals, not the percentages, in these formulas.
markup = margin / (1 - margin)
0.40 / 0.60 = 0.667
margin = markup / (1 + markup)
0.667 / 1.667 = 0.40Find the price for a target margin
To reach a set margin, divide the cost by 1 minus the margin. For a 40 percent margin on a cost of 60, that is 60 divided by 0.6, so a price of 100. The profit margin calculator does this in its second mode, and shows margin, markup and profit for any cost and price.
Next steps
Once you know the profit per unit, work out how many units you need to sell to cover your fixed costs. If you sell to consumers, remember that margins are calculated on the price before VAT.