Your monthly sales report lands. Product A did $50,000, Product B did $30,000, Product C managed $10,000. The instinct is obvious: Product A is the winner. But I’ve watched business owners build entire strategies around that instinct, only to discover six months later that Product A was barely breaking even once they factored in discounts, fulfillment, and the ad spend required to move it. Meanwhile, Product C, the quiet one, was funding the business. Revenue tells you what sold. It doesn’t tell you what those sales actually contributed.
This guide walks through how to calculate profitability at the individual product level, layer by layer, so you can answer the only question that matters: which products actually make money?
Product profitability measures the revenue retained from a product after subtracting the costs attributable to that product. At minimum, subtract COGS from net revenue to get gross profit. For stronger decision-making, also subtract variable selling costs like fulfillment, payment processing, and product-specific advertising to arrive at contribution. No single formula captures every business, so the right depth depends on what decision you’re making.
What product profitability actually means (and why your P&L won’t show it)
Company profitability asks “how’s the business doing?” Product profitability asks “how is this specific SKU performing?” Your profit and loss statement shows the first. It rarely shows the second.
A business can be profitable overall while carrying products that lose money on every unit. The reverse happens too: a modest seller with strong margins can quietly subsidize weaker products. I often see businesses where three or four SKUs generate most of the contribution, and everything else just comes along for the ride.
The product profitability ladder
I use a layered approach when advising business owners. This is a ProfitBooks editorial framework, not an accounting standard, but it keeps the analysis structured.
The Product Profitability Ladder (ProfitBooks Editorial Framework)
Level 1, Sales
What did the product sell for at list price?
Level 2, Net revenue
Revenue after discounts, returns, and refunds.
Level 3, Gross profit
Net revenue minus COGS.
Level 4, Contribution
Gross profit minus variable selling costs (payment processing, fulfillment, marketplace fees, product-specific ads).
Level 5, Product-level profitability
Contribution after any avoidable product-specific fixed costs.
Level 6, Business profit
After broader operating expenses.
Each level answers a different question. Stopping at Level 3 when your real problem lives at Level 4 is how “profitable” products quietly drain cash.
Phase 1: calculate net revenue
Start with gross sales per product. Then subtract discounts, returns, and refunds.
Here’s where business owners get caught: they use list price as their revenue number. A product listed at $100 with a 20% discount and a 5% return rate doesn’t generate $100 in revenue per unit. It generates closer to $76. The gap between list price and retained revenue is where profitability analysis starts, and where most spreadsheet models already go wrong.
Community discussions on Reddit’s r/shopify consistently flag this. Platform-level revenue totals hide product-level variation, and that makes the best seller look more profitable than it is.
Phase 2: determine COGS
COGS composition depends on your business model.
A retailer’s COGS is primarily the purchase cost of inventory. A manufacturer includes raw materials, direct labor, and production costs. An ecommerce seller might include product cost plus inbound freight and customs duties, depending on how they handle landed costs.
The friction warning I’d give here: many businesses undercount direct costs. Shopify’s own documentation distinguishes COGS from operating costs like marketing and admin, but fulfillment, inbound shipping, and packaging often fall into a gray area. If you’re importing goods and ignoring duties, your COGS is understated.
Verification check
Can you state the per-unit cost for each product, including freight and duties where applicable? If you’re pulling that number from memory rather than records, pause and get the actual figure first.
Phase 3: calculate gross profit and gross margin
A 60% gross margin sounds healthy. But margin percentage without volume context is half the picture. A product with 60% margin selling 50 units generates $3,000 in gross profit on a $100 price point. A product with 35% margin selling 2,000 units at $40 generates $28,000. The percentage alone doesn’t tell you which product is carrying the business.
Phase 4: identify variable selling costs
This is where the analysis moves past what most guides cover. Depending on your model, variable costs per product might include payment processing fees, marketplace referral fees, fulfillment and pick-and-pack labor, seller-funded shipping, packaging, sales commissions, product-specific advertising, and expected return handling costs.
Reddit’s r/FulfillmentByAmazon community describes this well: start with selling price minus COGS minus referral fee, then add the rest of the fee stack one layer at a time. The product that “looks profitable until I account for everything” is a recurring complaint across ecommerce forums.
I wouldn’t tell every business to include every cost above. The right cost layer depends on the decision you’re making. If you’re evaluating whether to keep selling on a marketplace, marketplace fees matter. If you’re setting a base price, COGS and payment processing are the floor.
The cost layer test
Before adding any cost to your product profitability calculation, run it through four questions.
1. Is this cost directly associated with the product?
2. Does it change when I sell more units?
3. Would the cost disappear if I stopped selling this product?
4. Am I using this calculation for financial reporting or a business decision?
These questions prevent you from mixing accounting COGS, variable selling costs, shared overhead, and business-wide operating expenses into one meaningless number. That mixing is the single most common mistake I see in product profitability spreadsheets.
Worked example: three products
All figures are illustrative.
| Metric | Product A | Product B | Product C |
|---|---|---|---|
| Units sold | 500 | 200 | 1,200 |
| Selling price | $100 | $150 | $25 |
| Gross sales | $50,000 | $30,000 | $30,000 |
| Discounts | $5,000 | $1,500 | $6,000 |
| Net revenue | $45,000 | $28,500 | $24,000 |
| COGS | $22,500 | $8,550 | $14,400 |
| Gross profit | $22,500 | $19,950 | $9,600 |
| Gross margin | 50.0% | 70.0% | 40.0% |
| Variable selling costs | $9,000 | $2,850 | $7,200 |
| Contribution | $13,500 | $17,100 | $2,400 |
| Contribution margin | 30.0% | 60.0% | 10.0% |
Product A has the highest revenue. Product B generates the most contribution. Product C moves the most units but contributes $2,400 total, and that’s before any overhead allocation. The best-selling product is not the most profitable product.
This plays out constantly in real catalogs. Consider a brand such as Shrishtvi, a premium fashion-jewelry label that sells a wide range of demi-fine pieces across earrings, necklaces, bracelets, anklets, and rings, with tiered discounts and free-gift promotions layered on top. A catalog like that, with many price points, frequent discounting, and product returns, is exactly the environment where two styles with similar gross sales can contribute very differently once discounts, fulfillment, and returns are subtracted. Ranking pieces by revenue alone would hide which ones are actually funding the business.
Should you allocate overhead?
Warehouse rent, admin salaries, general software costs. These are real. But dividing them equally across products can create false precision. If you spread $10,000 of monthly rent across 20 SKUs, each product “absorbs” $500, which might make a low-volume specialty item look unprofitable while a high-volume product looks artificially lean.
Contribution margin, kept clean of overhead, is more useful for incremental decisions: should I run this promotion, should I keep this SKU on this marketplace, should I increase ad spend here? Fully allocated cost views can inform longer-term portfolio decisions, but only when the allocation method is reasonable and consistent.
Practitioners on Reddit’s r/smallbusiness argue about this constantly. Some recommend keeping overhead out of product profitability entirely and treating it as a separate business-level breakeven problem. I lean that direction for most small businesses.
Margin vs. markup (they’re different numbers)
Markup is based on cost. Margin is based on selling price.
A product costing $40 sold for $100 has a 150% markup but a 60% margin. Confusing the two leads to pricing errors. If you set prices using “60% markup” thinking it gives you 60% margin, your actual margin is 37.5%. That gap compounds across thousands of units.
When high revenue is actually a problem
A product can generate $50,000 in monthly revenue and still contribute almost nothing. Heavy discounting, high COGS, expensive fulfillment, high return rates, and costly customer acquisition can consume the entire sale. Revenue must be interpreted alongside unit economics. I’ve seen businesses discontinue their “hero product” and watch overall profitability improve because the resources freed up went to higher-contribution items.
Where this approach fails
If your business sells fewer than five products with stable costs and no marketplace or fulfillment complexity, a detailed contribution analysis adds overhead without changing decisions. A simple gross profit calculation per product, updated quarterly, is probably enough. The layered approach described here earns its keep when you’re selling across channels, running promotions, or managing dozens of SKUs with different cost structures. For service businesses, product profitability isn’t the right frame at all; analyze by client, project, or engagement instead.
Start your analysis from clean numbers
ProfitBooks connects accounting, invoicing, inventory, and purchase records in one place, so sales, discounts, returns, and costs stay matched to the right products and your profitability numbers start from accurate data.
What to do with the results
The numbers mean nothing without action. If margin is too low, review pricing or negotiate supplier costs. If contribution is weak, examine fulfillment costs, marketplace fees, or ad spend per unit. If a product has strong margins but slow inventory turnover, it’s tying up cash that could work harder elsewhere. If profitability looks inconsistent month to month, check your costing methodology and reconcile inventory data.
Never discontinue a product based on one metric alone. A low-margin product might drive repeat purchases or anchor a bundle. Context matters.
The product profitability quadrant (ProfitBooks editorial framework)
| Scenario | Action |
|---|---|
| High sales + high contribution | Protect and scale |
| High sales + low contribution | Investigate pricing and costs |
| Low sales + high contribution | Investigate demand and positioning |
| Low sales + low contribution | Strategic review |
| High margin + slow inventory | Review cash and inventory efficiency |
This framework prioritizes investigation. It is not an automatic rule for discontinuing products.
How connected software helps
Product profitability depends on connected data: sales matched to discounts, returns matched to SKUs, purchases matched to inventory, expenses matched to products. When that data lives in separate spreadsheets, the reconciliation work is where most people give up. Pre-building formulas in a spreadsheet helps, but maintaining them month after month is where the process breaks down.
Tools like ProfitBooks that connect accounting, invoicing, inventory, and purchase records in one system make it easier to maintain the underlying data you need. The software won’t automatically tell you which products to discontinue, but it keeps the financial and inventory records clean enough that your analysis starts from accurate numbers rather than guesswork.
Quick FAQ
How do I calculate product profitability if I have shipping and ad spend?
Start with net revenue minus COGS for gross profit. Then subtract shipping, ad spend, and other variable selling costs to get contribution. Keep overhead separate unless you have a defensible allocation method.
Should overhead be included in product profitability?
It depends on the decision. For incremental choices (promote this product, keep it on a marketplace), contribution margin without overhead is cleaner. For long-term portfolio decisions, a reasonable overhead allocation can add perspective.
What’s the difference between margin and markup?
Margin divides profit by selling price. Markup divides profit by cost. A $60 profit on a $100 sale is 60% margin but 150% markup on the $40 cost.
How do I know which products are loss leaders?
Calculate contribution per unit after all variable selling costs. If contribution is negative or near zero, the product only makes sense if it drives measurable additional purchases.
How often should I review product profitability?
Fast-moving ecommerce with volatile ad costs might need monthly review. Stable wholesale lines with fixed pricing can go quarterly. Review whenever costs, prices, or channel mix change materially.
Can a best-selling product actually lose money?
Yes. High volume with heavy discounting, expensive fulfillment, and high return rates can push contribution below zero even when gross sales look strong.
How do discounts affect product profitability?
A 20% discount on a $100 product with $50 COGS drops gross profit from $50 to $30. That’s a 40% reduction in profit dollars from a 20% price cut. Discounts hit harder than most owners expect.
The bottom line
Revenue tells you what moved. Product profitability tells you what those sales actually contributed to the business. The next problem you’ll hit after building this analysis: keeping the data current as costs shift and new products launch. Start with your top ten SKUs, get the contribution numbers right, and expand from there.
Know which products actually make money
ProfitBooks keeps your accounting, invoicing, inventory, and purchase records connected, so your profitability numbers stay accurate as costs shift and new products launch.
