Margin, markup and profit

The calculator keeps profit, margin and markup separate. Profit is selling price minus entered cost; margin uses selling price as its percentage base, while markup uses cost as its percentage base.

Five pricing paths analyse cost and selling price, derive selling price from target margin or markup, and derive cost from selling price and margin or markup. The break-even panel separately provides break-even, profit at quantity and target-profit quantity.

Target margin uses cost ÷ (1 − margin/100) and accepts 0 ≤ margin < 100. Target markup uses cost × (1 + markup/100) and accepts a non-negative markup. Reverse cost paths use selling price × (1 − margin/100) and selling price ÷ (1 + markup/100).

Contribution per unit is selling price minus variable cost per unit. Break-even is reachable only with a positive contribution; the panel then distinguishes the exact quantity from the minimum whole quantity and break-even revenue. A non-positive contribution is the valid `unreachable` state, not a successful break-even result.

The cost-60/selling-price-80 case proves that 25% margin is not 25% markup. The quantity cases separately test break-even, profit at quantity and a target-profit quantity.

Cost 60 and selling price 80: profit 20, margin 25%, markup 33.33%. Fixed costs 10,010, price 50 and variable cost 30: exact break-even 500.5 units, minimum whole quantity 501, revenue 25,025.

With selling price zero, margin is undefined; with cost zero, markup is undefined. The service keeps those quotients undefined rather than displaying NaN or Infinity. Positive costs and selling prices may still produce a negative profit and negative percentages.

EUR, USD, GBP and CHF are display formats only, with no exchange-rate conversion. The model does not add discounts, sales tax, other taxes, fixed overhead outside the chosen panel or a complete company profit statement; it is not accounting, tax or pricing advice.