Profit margin vs markup: a 100-cost worked example

Adding 50% to cost does not produce a 50% profit margin. Margin uses selling price as its denominator; markup uses cost. The same profit amount can therefore produce two different percentages.

Cost of 100, selling price of 150

Assume no extra costs and consistent tax treatment for both values.

• Profit: 150 − 100 = 50
• Margin: 50 ÷ 150 × 100 = 33.33%
• Markup: 50 ÷ 100 × 100 = 50%

Enter these values in the profit margin calculator. It displays both ratios, making the denominator difference visible.

Price for a target margin

For target margin m, selling price = total cost ÷ (1 − m). Express the percentage as a decimal: 40% becomes 0.40.

At cost 100, a 40% margin requires 100 ÷ 0.60 = 166.67. Adding only 40% to cost gives a price of 140 and a margin of approximately 28.57%.

If total cost is 120, the same target margin requires a price of 200. This formula assumes costs are known amounts. Fees calculated as a percentage of selling price need a separate calculation rather than being treated as a fixed cost without adjustment.

Include the extra costs

Add 20 of packing and processing costs to product cost 100. At price 150, profit is now 30, margin is 20% and markup is 25%. Count each cost once. Do not add packaging again if it is already included in the product cost.

Be careful with zero denominators

Margin is undefined when sales value is zero; markup is undefined when cost is zero. The calculator may display zero in these edge cases. Do not treat that display as a meaningful profitability ratio. Review the profit amount and the underlying assumptions instead.

Once unit economics are clear, use the break-even guide to estimate how many units cover fixed costs. Marketplace sellers should first account for commission and shipping deductions.

Recheck margin after a discount

At a cost of 100 and a selling price of 150, the simplified difference is 50 and margin is 33.33%. A 10% price discount reduces the selling price to 135. With cost unchanged, the difference becomes 35 and margin becomes 25.93%. A 10% price reduction has reduced the amount remaining per unit by 30% in this example.

Try selling prices of 150 and 135 in the calculator. Keep the tax treatment consistent between cost and price. If commissions, shipping or other expenses are excluded, do not interpret the result as net business profit.

Before running a promotion, record the regular price, discounted price and total unit expenses together. Evaluate separately whether extra sales volume could compensate for the lower contribution per unit.