How to Track Profitability by SKU

The 80/20 rule applies to your product catalog: roughly 20% of your SKUs generate 80% of your profit. The problem is that most ecommerce brands have no idea which 20% that is. They look at store-level margins, see a number that feels acceptable, and assume every product is pulling its weight. It is not.

Tracking profitability by SKU means calculating the true profit each product generates after every variable cost is accounted for — not just COGS, but shipping, fees, ad spend, and returns. When you do this, you almost always find products you thought were winners are actually breaking even, and products you ignored are quietly carrying the business.

This guide walks through why store-level margins lie, what per-SKU profitability actually includes, how to set up tracking (from spreadsheets to dedicated tools), and a decision framework for what to do once you have the numbers. If you want to run the math on your own products as you read, open our free profit margin calculator in another tab.

Why Store-Level Margins Lie

Your Shopify dashboard says you made a 40% gross margin last month. That sounds healthy. But store-level margins are blended averages, and blended averages hide the products that are destroying your profitability.

Here is a simple example. Imagine a store with three SKUs:

The blended margin of 33% looks fine. But the Travel Kit is contributing almost nothing. Every hour spent merchandising, photographing, and running ads for that SKU is wasted effort. Worse, if its return rate spikes or shipping costs increase even slightly, it flips negative — and the store-level number barely moves, so you never notice.

Blended margins are a comfort metric. They tell you the store is doing okay in aggregate. They do not tell you which products to double down on, which to reprice, and which to kill. Per-SKU profitability does.

This is the same problem that shows up at the channel level. As we covered in our guide to revenue vs. profit, a growing top line can mask a shrinking bottom line. The same is true at the product level: a growing catalog can mask the fact that only a handful of SKUs actually make money.

What Per-SKU Profitability Actually Includes

Most founders stop at COGS. They subtract the cost of manufacturing from the selling price and call it margin. But COGS is only the starting point. True per-SKU profitability accounts for every variable cost attached to selling one unit of that product.

Here is the full cost stack, line by line:

1. Cost of Goods Sold (COGS) — The manufacturing or wholesale price per unit. Include raw materials, labor, and inbound freight. If you buy from a supplier overseas, add tariffs and duties. Your real COGS is almost always higher than the factory quote.

2. Packaging — Boxes, inserts, tissue paper, branded tape, labels. Small per unit, but it adds up. A $2 unboxing experience on a $25 product is 8% of revenue.

3. Outbound shipping — What it costs to get the product to the customer. If you offer free shipping, this is a direct margin hit. Heavier and bulkier products eat more here. Calculate the actual average shipping cost per SKU, not a blended average across all products.

4. Transaction and platform fees — Payment processing (typically 2.9% + $0.30 per transaction), Shopify plan fees allocated per order, and marketplace commissions if you sell on Amazon or other platforms. These are variable — they scale with each sale.

5. Allocated ad spend — This is the cost most brands skip, and it changes everything. If you spend $3,000 on Meta ads and those ads drive 200 orders, your blended ad cost per order is $15. But some products get more ad spend than others. Allocate spend by the SKUs your campaigns actually push. A product that takes $25 in ad spend to sell looks very different from one that takes $5.

6. Returns — The return rate on a product multiplied by the cost of each return (reverse shipping, restocking, lost resale value). A 20% return rate on a $40 product with $8 reverse shipping and 50% resale loss effectively subtracts $5.60 from every unit sold. Learn more in our breakdown of how to calculate true profit.

When you stack all six layers, you get the true profit margin for each SKU. Here is what it looks like for a product at three different price points:

The $25 product barely survives. One small cost increase — a shipping rate hike, a rise in CPMs — and it goes negative. The $65 product is healthy. The $120 product is the engine. This is why knowing your numbers by SKU matters: if you are spending equal ad budget across all three, you are subsidizing a near-loss product with profits from your winners.

How to Set Up SKU-Level Tracking

You have three options, depending on your catalog size and technical comfort. Pick the one that matches where you are now — you can always upgrade later.

Option 1: Spreadsheet Method (Under 50 SKUs)

A Google Sheet or Excel workbook is the fastest way to start. Create a tab with one row per SKU and columns for every cost line item listed above. Calculate net profit and margin percentage for each row.

Columns to include: SKU name, selling price, COGS, packaging, average shipping cost, processing fee percentage, platform fee, monthly ad spend allocated to that SKU, monthly units sold, return rate, return cost per unit, net profit per unit, margin percentage.

The limitation is maintenance. Shipping rates, ad costs, and return rates change regularly. If you do not update the sheet monthly, the numbers drift. But for a brand with a focused catalog, this is the right starting point.

Option 2: Shopify Reports + Export (50-200 SKUs)

Shopify's built-in reporting gives you product-level revenue and COGS if you enter cost-per-item on each product. Export the “Sales by product” report, then enrich it in a spreadsheet with shipping, fees, ad spend, and return data. This hybrid approach leverages your existing data while adding the cost layers Shopify does not track natively.

For ad spend allocation, pull your campaign data from Meta or Google Ads Manager and match campaigns to the SKUs they promote. If a campaign pushes multiple products, split the spend proportionally by revenue or by units sold.

Option 3: Dedicated Tools (200+ SKUs or Multi-Channel)

Once your catalog grows or you sell across multiple channels (Shopify + Amazon + wholesale), dedicated profitability tools become necessary. These connect directly to your store, ad accounts, and shipping providers to calculate per-SKU profit automatically.

True Margin is built for exactly this — giving ecommerce founders real-time visibility into per-product profitability without the manual data wrangling. The key advantage of any dedicated tool over spreadsheets is automated data ingestion: costs update as they change, so your profitability numbers are always current.

Regardless of which method you choose, the unit economics are the same. The goal is to get a single number — net profit per unit — for every product you sell.

The SKU-Level Decision Framework

Once you have per-SKU profitability data, every product in your catalog falls into one of four buckets. Here is how to act on each:

The hardest decision is cutting a high-revenue, low-margin product. It feels counterintuitive to kill something that sells. But a SKU doing $10,000/month in revenue at 3% margin is contributing $300 to the business while consuming ad budget, warehouse space, customer service time, and management attention. That same ad budget redirected to a 30% margin product would generate ten times the profit.

Run this framework quarterly. Products move between buckets as costs change, so a SKU that was in the “Scale” bucket last quarter might slip to “Maintain” if shipping costs rose or ad CPMs increased.

Real Examples at Different Price Points

The dynamics of SKU profitability change significantly depending on your price point. Here are three common scenarios:

Low-Ticket ($10-$30): The Shipping Squeeze

Low-priced products are the most vulnerable to shipping costs eating margin. A $15 phone case with $3 COGS looks like a 80% gross margin product. But add $4.50 shipping (free shipping to customer), $0.74 in processing fees, $5 allocated ad spend, and a 12% return rate costing $0.80 per unit blended, and your net margin drops to $1.96 per unit — just 13%.

The fix: Bundle low-ticket items to increase order value. Two phone cases at $25 share one shipping cost, one transaction fee, and often one ad click. The per-unit economics improve dramatically.

Mid-Ticket ($40-$80): The Ad Spend Allocation Problem

Mid-priced products typically have healthy enough gross margins but live or die based on how much ad spend they absorb. A $60 product with $15 COGS, $6 shipping, and $2 in fees has a 61.7% gross margin. But if it takes $20 in ad spend to sell each unit, net margin drops to 28.3%. If ad spend climbs to $30 per unit (common in competitive categories), margin drops to 11.7%.

The fix: Track COGS and ad spend at the SKU level religiously. Shift budget from products with high cost-per-acquisition to those with lower acquisition costs and similar or better margins.

High-Ticket ($100+): The Return Rate Risk

Higher-priced products usually have the best unit economics — until returns hit. A $150 product with 50% gross margin looks outstanding. But high-ticket items tend to have higher return rates (customers have higher expectations), and each return is expensive: $12 reverse shipping, $20 in lost resale value, and customer service time. A 25% return rate at those costs subtracts $8 from every unit sold.

The fix: Invest in product detail pages, sizing guides, and pre-purchase education to reduce returns. Every percentage point of return rate reduction drops straight to the bottom line on high-ticket products.

Common Mistakes When Tracking SKU Profitability

Even brands that commit to per-SKU tracking often get it wrong. Here are the mistakes that lead to bad decisions:

1. Using COGS as the only cost. If your “margin” calculation stops at selling price minus COGS, you are looking at gross margin, not profitability. Gross margin ignores shipping, fees, ad spend, and returns — the costs that determine whether you actually keep any of that margin. See our guide on how to calculate profit margin for the full formula.

2. Spreading ad spend evenly across all SKUs. If you allocate your total ad spend equally across all products, you misattribute cost. A product with zero ad support gets burdened with spend it did not incur, while a heavily promoted product looks more profitable than it is. Allocate by campaign, not by catalog.

3. Ignoring return rates by product. Blended return rates hide product-specific problems. Your overall return rate might be 12%, but your sizing-dependent apparel SKU might be at 28% while your accessories are at 4%. The apparel SKU's true margin is dramatically worse than the blended number suggests.

4. Forgetting about payment processing fees. The standard 2.9% + $0.30 per transaction does not sound like much, but it compounds. On a $20 product, processing fees are $0.88 — that is 4.4% of revenue. On a $100 product, fees are $3.20, or 3.2%. Lower-priced products carry a disproportionately higher fee burden.

5. Not updating costs regularly. Supplier prices change. Shipping rates adjust quarterly. Ad CPMs fluctuate seasonally. If your profitability model uses costs from six months ago, you are making decisions on stale data. Update inputs monthly at minimum.

6. Tracking revenue instead of profit when making decisions. This is the most common and most expensive mistake. Brands kill their highest-margin product because it “only” does $5,000/month in revenue, then pour resources into a $20,000/month revenue product that nets 4%. Revenue is vanity, profit is sanity. The only number that matters at the SKU level is net profit per unit.

Putting It All Together: A Monthly SKU Profitability Review

Here is a repeatable process you can run on the first of every month. It takes about two hours and prevents you from scaling products that quietly lose money.

Step 1: Export last month's sales data by product — units sold, revenue, and refunds.

Step 2: Update your cost inputs. Check for any changes to COGS (new supplier quotes, tariff changes), shipping rates (carrier rate cards update quarterly), and platform fees.

Step 3: Pull ad spend by campaign and allocate to the SKUs each campaign promoted. For broad campaigns, split proportionally by revenue generated.

Step 4: Calculate return rate and return cost per SKU for the month. Do not use blended averages — pull the actual return data by product.

Step 5: Compute net profit per unit and margin percentage for every SKU. Sort by margin percentage. Categorize each into Scale, Maintain, Discount, or Cut using the framework above.

Step 6: Take action. Shift ad spend toward Scale products. Initiate liquidation on Discount products. Kill the Cut products. Document decisions so you can track the impact next month.

The brands that do this consistently — month after month — are the ones that escape the trap of growing revenue while profit stays flat. They do not need better products or more traffic. They need better visibility into which products actually deserve investment. That is exactly what tracking profitability by SKU gives you.

Frequently Asked Questions

What does it mean to track profitability by SKU?

Tracking profitability by SKU means calculating the true profit each individual product generates after subtracting all variable costs — COGS, shipping, marketplace and payment processing fees, allocated ad spend, and returns. It replaces blended store-level margins with per-product visibility so you can see which SKUs actually make money and which ones silently lose it.

How often should I review SKU-level profitability?

At minimum, review SKU profitability monthly. If you run paid ads or frequent promotions, review weekly. Costs like shipping rates, ad CPMs, and return rates shift constantly, so a product that was profitable last quarter may not be profitable today. Quarterly deep-dives are useful for strategic decisions like discontinuing products or adjusting pricing.

What costs should I include in per-SKU profit calculations?

Include every variable cost tied to selling that product: cost of goods sold, inbound freight, packaging, outbound shipping, payment processing fees (typically 2.9% + $0.30), marketplace or platform fees, allocated advertising spend, and the cost of returns including reverse shipping and restocking. Exclude fixed overhead like rent, salaries, and software — those are covered by your aggregate contribution margin.

Can I track SKU profitability in a spreadsheet?

Yes, a spreadsheet works well for stores with fewer than 50 SKUs. Create columns for selling price, COGS, shipping cost, fees, allocated ad spend, and return rate. Calculate net profit per unit and margin percentage for each row. The limitation is that spreadsheets require manual data entry and do not update automatically as costs change, so they become hard to maintain as your catalog grows.

What is a good profit margin for an individual SKU?

After all variable costs including allocated ad spend, a healthy SKU should deliver at least 15-20% net contribution margin. SKUs below 10% are fragile — one cost increase or a small dip in conversion rate can push them negative. Hero SKUs in a well-optimized catalog often sit between 25-40%. Use our profit margin calculator to check where your products land.