The formula, without the mystery.
Margin = (price − cost) / price; markup = (price − cost) / cost
A worked example
A product costing 20 and selling for 50 has 30 gross profit, a 60% gross margin and 150% markup. A 50% markup does not mean a 50% margin.
What if the cost is zero?
Markup has a zero denominator and is undefined. This tool asks for a positive cost so both measures remain meaningful.
Keep the assumptions consistent
Use one planning period and one currency. Enter amounts consistently excluding sales tax or VAT. These simplified models do not account for uncertainty, inventory limits, working capital or progressive taxes. Results are planning estimates.