Margin and markup use different bases
Margin divides profit by revenue, while markup divides profit by cost; the percentages are not interchangeable.
Operating margin and leveraged-position risk
Measure what survives discounts, returns, variable cost, overhead, and leverage
Build a unit-economics and break-even model, solve a target-margin price, stress price and volume, then evaluate cash required, interest, equity, and margin-call exposure for a stock position.
Plan with context
Margin can mean business profitability or collateral supporting borrowed exposure.
In operations, discounts, returns, variable costs, fixed costs, and volume determine usable profit. In trading, borrowed capital amplifies equity changes and can trigger forced liquidation.
Contribution pays fixed cost first
Revenue remaining after variable cost must cover overhead before the business creates operating profit.
Discounts compound with returns
A discount reduces collected price, and returns reduce realized sales again, often producing a larger margin loss than either headline percentage suggests.
Break-even is volume-dependent
Fixed cost divided by contribution per unit estimates the sales volume required before operating profit becomes positive.
Initial margin controls leverage
The investor’s cash percentage determines borrowed funds and how strongly the position’s gain or loss affects deposited equity.
Maintenance margin creates a threshold
If account equity falls below the broker’s requirement, more collateral or forced liquidation may follow—sometimes before a simplified formula’s price.
Included
Unit cost, list price, volume, variable and fixed cost, discount, returns, tax, target contribution margin, gross margin, markup, break-even, price-volume scenarios, stock shares and prices, initial and maintenance margin, borrow interest, margin-call estimate, leveraged return, and Chart.js risk curve.
Not included
Inventory methods, payment fees, shipping, working capital, product mix, tax-return rules, dividends, commissions, short sales, options, changing loan rates, house requirements, liquidation slippage, or broker discretion.
Use it well
Reconcile realized—not listed—prices and every variable cost, stress both price and volume, and leave a meaningful equity buffer above a broker’s maintenance requirement.