Every product has a hidden answer: how much money you actually keep from each sale. That figure — profit per unit — decides whether your business is viable, whether you can afford a paid ad, and whether you should raise the price or cut the cost instead. This calculator works it out for you from the five numbers that matter: what you charge, what the product costs to make, what shipping really runs, your fixed monthly overhead, and how many units you move.
Slide the inputs and the result card updates instantly. It breaks the math into contribution margin, fixed cost per unit, net profit per unit, profit margin, total monthly profit, and the number of units you must sell each month to break even.
How to Use
- Enter the Sale Price per Unit — the final amount the customer pays you, after discounts and coupons.
- Type your Cost of Goods Sold (COGS) — factory cost, wholesale price, materials and direct labor for one unit.
- Add Shipping & Fulfillment per Unit — postage, packaging, labels and warehouse handling. Many sellers forget this line and are shocked when margin evaporates.
- Fill in Other Variable Cost per Unit — payment processing fees, platform commissions, or ad spend that scales with every order. Leave it at zero if you have none.
- Enter your Monthly Fixed Costs (Overhead) — rent, software, salaries and subscriptions that stay the same whether you sell one unit or a thousand.
- Set Units Sold per Month — your average monthly volume. Fixed costs are spread across this number, so the same overhead feels tiny at high volume and crushing at low volume.
The result card then shows your contribution margin per unit (what each sale contributes toward overhead), the fixed cost absorbed by each unit, your net profit per unit, the margin percentage, your total monthly profit, and your monthly break-even point.
The Formula
Profit per unit comes from the standard unit-economics model taught in every introductory accounting course:
Profit per Unit = Sale Price − COGS − Shipping − Other Variable Costs − (Fixed Costs ÷ Units Sold)
Worked example on the default numbers: price $25, COGS $12, shipping $3, other variable cost $0, monthly fixed overhead $5,000, volume 1,000 units. Contribution per unit is 25 − 12 − 3 = $10. Fixed cost per unit is 5,000 ÷ 1,000 = $5. Profit per unit is 10 − 5 = $5, which is a 20% margin (5 ÷ 25). Total monthly profit is 1,000 × 5 = $5,000, and the break-even point is 5,000 ÷ 5 = 1,000 units — meaning below 1,000 units a month you lose money, and above it every extra unit drops $10 of pure contribution to the bottom line.
Notice the two-layer structure. The contribution margin ($10) is what pays for the business; the net profit per unit ($5) is what is left after overhead. If profit per unit is negative, raising volume alone cannot save you — you must cut variable cost, raise price, or shrink overhead.
Why Volume Changes the Answer
A product that loses money at 100 units a month can be profitable at 10,000. The reason is the fixed-cost line. At 100 units, the same $5,000 overhead weighs $50 onto every unit — instantly turning a $10 contribution into a $40 loss. At 10,000 units, that overhead shrinks to $0.50 per unit, and the same product banks $9.50 on every sale. This is why startups talk about "unit economics": the per-unit model must be sound at mature volume, and the question is how long your cash runway lasts before you get there.
Examples
Example 1 — A handmade candle seller. Price $25, wax and wicks cost $12, shipping $3, no other variable costs, fixed overhead $500 a month for studio rent and software, selling 100 candles. Contribution is $10 per unit; fixed cost per unit is $5; profit per unit is $5 at a 20% margin, and monthly profit is $500. Break-even is 100 units a month — right at current volume. Cutting COGS to $10 pushes profit per unit to $7 and margin to 28%, which is why sourcing cheaper wax matters more than any marketing campaign.
Example 2 — An Amazon FBA electronics reseller. Price $40, product cost $24, FBA shipping and handling $6, platform referral fee 15% ($6), monthly fixed overhead $8,000 (office, software, ads team), selling 2,000 units. Contribution per unit is 40 − 24 − 6 − 6 = $4; fixed cost per unit is $4; profit per unit is $0 — razor thin, exactly break-even. Raising the price by $2 adds almost $2 straight to profit per unit and lifts margin from 0% to 5%, illustrating how fragile high-volume, low-margin businesses are.
Example 3 — A million-dollar scale test. Price $25, COGS $12, shipping $3, fixed overhead $2,000,000 a month, selling 1,000,000 units. Fixed cost per unit collapses to $2, so profit per unit rises to $8 (32% margin) and total monthly profit hits $8,000,000. The calculator handles volumes this large so you can sanity-check projections before betting inventory on them.
FAQ
How do I calculate profit per unit?
Subtract every cost tied to one unit from the sale price: profit per unit = price − COGS − shipping − other variable costs − (monthly fixed costs ÷ units sold). On a $25 item that costs $12 to make, ships for $3, and carries $5 of allocated overhead, profit per unit is $5.
What is the difference between contribution margin and profit per unit?
Contribution margin per unit is price minus variable costs only (COGS, shipping, fees). Profit per unit goes one step further and also subtracts your fixed overhead spread across the units you sell. Contribution margin shows whether the product itself is worth selling; profit per unit shows whether the whole business is actually making money.
What is a good profit margin per unit?
Consumer retail often runs at 20–50% gross margin, while online marketplaces and high-volume reselling can sit near 10–20%. A healthy net profit margin per unit for a small business is usually 10% or more. Anything below 5% leaves almost no room for returns, ads, or unexpected costs.
How many units do I need to sell to break even?
Divide monthly fixed costs by profit per unit. With $5,000 of overhead and $5 of profit per unit, you need 1,000 units a month to break even. Below that volume you lose money; every unit above it is nearly pure contribution. Raise price or cut variable costs and the break-even line drops fast.
Why does my profit per unit change when I change monthly volume?
Because fixed costs are constant in dollars but variable in per-unit terms. At low volume the overhead is spread thinly across few units, so each unit absorbs a large share; at high volume the same overhead is divided across many units, shrinking the per-unit burden. This is why per-unit profit rises as you scale.
Should I include shipping and platform fees in profit per unit?
Yes. If you leave shipping, payment processing, and marketplace commissions out, your per-unit profit will look much better than reality. The most common cause of "profitable on paper, broke in the bank" is treating variable costs as if they were fixed — or ignoring them entirely.
Disclaimer
This profit per unit calculator is provided for informational purposes only and does not constitute financial, tax, or accounting advice. Results are estimates based on the inputs you enter; actual costs, fees, taxes, and returns vary by product, channel, region, and season. Always confirm your numbers with a qualified accountant or bookkeeper before making pricing, inventory, or advertising decisions.