The denominator changes the meaning
Margin and markup both describe the gap between cost and selling price, but they divide that gap by different numbers. Margin uses revenue; markup uses cost. This is why a pricing instruction such as “add 40%” needs clarification before someone changes a price list.
Suppose an item costs 60 and sells for 100. Its 40 profit is 40% of the selling price and about 66.67% of cost. A 40% markup would instead produce a price of 84. Both calculations are internally consistent; they answer different questions. Use the margin and markup calculator to name the intended target explicitly.
Build a cost that matches the decision
A direct product cost might include purchase or production costs. A broader order cost might also include packaging and shipping. Decide which definition you are using and keep it consistent across products. Otherwise a comparison can appear precise while mixing different expenses.
Do not label a per-item contribution as final business profit when rent, staff costs, selling fees or other expenses are still excluded. The break-even calculator can show how contribution covers fixed operating costs. The Etsy fee calculator can help separate the charges on a modeled marketplace order.
Expect a small difference after price rounding
A target formula can produce more than two decimal places. With cost 1 and target margin 33%, the exact target price is slightly below 1.50. Rounding the price down to 1.49 would miss that target; this tool rounds upward to 1.50 and reports the percentage actually achieved.
The rounding rule is a pricing-model choice, not a claim about the best commercial price. Discounts, demand, competitors and customer willingness to pay are outside the arithmetic.
Keep a reproducible pricing note
Save the cost definition, target type, target percentage and proposed price together. When a supplier cost changes, you can then distinguish a changed input from a changed pricing rule. Compare results in the same currency and make any currency conversion separately with a clearly chosen rate.