Keystone Pricing Calculator

How it is calculated

Enter the unit cost you pay for one item, in US dollars. The tool applies the keystone rule: price = cost × 2, profit = price − cost, which always equals the cost. The margin shown is a fixed 50.00%, because doubling the cost always leaves half of the selling price as gross profit, whatever the cost is.

Margin here means margin on the selling price: profit / price. Measured against cost, the same sale is a 100% markup. A negative cost gives no result, and a cost of zero returns zeros. The tool has no field for a different multiplier, shipping, tax or discounts. For a different target margin, use price = cost / (1 − margin).

Common mistakes

• Confusing margin with markup. Doubling the cost is a 100% markup but only a 50% margin, and quoting one as the other misstates profit.
• Using landed cost incorrectly. If freight, duty or packaging are left out of the unit cost, the true margin is below 50%.
• Treating the result as net profit. It is gross profit, and rent, staff, card fees and returns still come out of it.
• Applying keystone to every category. Products with thin margins, such as electronics or groceries, often cannot be sold at double cost.
• Entering the intended selling price instead of cost. The tool doubles whatever you type, so the answer would be twice your target price.