Profit Margin vs Markup: Pricing Products Correctly

Margin and markup describe the same transaction from two different denominators. Confusing them is one of the most common and most expensive arithmetic errors in small business — and it always errs in the same direction: you charge too little.

The two formulas

margin % = (price − cost) / price   × 100
markup % = (price − cost) / cost    × 100

Margin is share of revenue. Markup is share of cost. On a product that costs $60 and sells for $100:

Margin = (100 − 60) / 100 = 40%
Markup = (100 − 60) / 60 = 66.7%

Same $40. Two very different-looking percentages.

The confusion that costs real money

The classic error: you want a 40% margin, so you add 40% to cost. $60 × 1.40 = $84. But $84 gives you a margin of (84 − 60) / 84 = 28.6%, not 40%. You have just given away over eleven points of margin on every unit.

To get a target margin, divide rather than multiply:

price = cost / (1 − target_margin)
price = 60 / (1 − 0.40) = $100

Target margin	Divide cost by	Equivalent markup
20%	0.80	25%
30%	0.70	42.9%
40%	0.60	66.7%
50%	0.50	100%
60%	0.40	150%
70%	0.30	233%

Landed cost: what actually goes in COGS

A margin calculated on the supplier invoice alone is fiction. The number that belongs in the formula is landed cost — everything required to get one sellable unit into your hands:

Unit price from the supplier
Inbound freight, divided per unit
Customs duty and import fees
Non-recoverable taxes
Packaging and assembly
An expected damage or defect rate

For e-commerce specifically, two further deductions belong in any margin you plan to spend against: payment processing (roughly 2.5–3.5% of the sale) and expected returns. A 40% gross margin with a 3% processor fee and a 10% return rate is closer to 30% in reality.

Breakeven and contribution margin

Per-unit margin tells you whether a sale is worth making. Contribution margin tells you how many sales keep the business alive:

contribution_per_unit = price − variable_cost_per_unit
breakeven_units       = fixed_costs / contribution_per_unit

With $8,000 of monthly fixed costs and $34 of contribution per unit, breakeven is 236 units a month. That single number reframes most pricing debates: a $4 price increase here drops breakeven to 211 units — a 10% easier month, from a change most customers will not notice.

What a discount really costs

A discount does not reduce revenue by its percentage — it reduces profit by far more, because the cost side does not move. At 40% margin, a 20% discount cuts profit in half.

Discount	At 30% margin	At 40% margin	At 50% margin
10%	−33% profit	−25% profit	−20% profit
20%	−67% profit	−50% profit	−40% profit
30%	−100% profit	−75% profit	−60% profit
40%	Loss	−100% profit	−80% profit

The volume you need to break even on a discount follows from the same arithmetic:

required_volume_increase = discount / (margin − discount)

20% off at 40% margin → 0.20 / (0.40 − 0.20) = 1.00 → sales must double

Which is the useful test before running a promotion: not "will this sell more?" but "will this sell twice as much?" If the honest answer is no, the promotion is a transfer from your margin to your customers — sometimes worth it deliberately, rarely worth it by accident.