01Start with landed unit cost
Use the cost per expected sellable unit from a complete landed-cost estimate, not the supplier's unit price. Freight, duty, brokerage, inspection, packaging and expected unsellable units can materially change the amount inventory must recover.
02Separate ticket price from selling price
The ticket price is what the business plans to display. The expected selling price reflects ordinary discounting. Model both. A product that works only when every unit sells at full price needs a separate markdown and clearance scenario.
03Do not confuse margin and markup
Gross or contribution margin divides profit by selling price. Markup divides the difference between selling price and cost by cost. The percentages are not interchangeable. Record which formula a buyer, supplier or marketplace uses before comparing targets.
04Include percentage deductions
Marketplace commissions, payment processing and a returns or loss allowance usually move with selling price. Enter each rate separately. Check whether a provider applies the fee before or after tax, shipping, refunds or other adjustments; the calculator uses a simplified selling-price base.
05Include per-unit operating costs
Add pick-and-pack, local fulfillment, retail packaging or other variable costs that exist for each sale. Keep rent, salaries, software and broad marketing outside this unit view unless the business has a documented allocation method.
06Work backward from a target
The maximum landed-cost result shows what can remain for the product after the target contribution margin and entered variable deductions. It is a negotiation and assortment screen, not a promise that the target price or sales volume is achievable.
07Run base, discount and stress cases
Use at least three scenarios: normal selling price, a realistic promotion and a slower clearance case. Change returns, fees and fulfillment when the channel changes. Compare contribution per unit and total exposure for the planned quantity.
08Reconcile actual performance
After sales begin, replace assumptions with actual selling price, refunds, fees, fulfillment and sellable-unit data. Preserve the estimate beside the result. The variance improves future buy-cost limits, pricing and reorder decisions.