How to Tell Which Products Actually Make You Money

For most eCommerce brands, tracking top-line revenue is easy. Tracking true profitability is remarkably difficult.

If you ask an operations director which products are their bestsellers, they can usually pull a report in seconds. But if you ask them which products actually generate the most cash after accounting for fulfilment, channel fees, and shipping, the answer often requires hours of spreadsheet gymnastics.

This data gap is a massive operational vulnerability. If you cannot see what it costs to pick, pack, and ship a specific item through a specific channel, you are essentially flying blind on profitability. 

Here is a practical look at why standard reporting fails growing brands, and how to uncover your true SKU-level contribution margin.

The Problem with Standard Gross Margin

When brands attempt to measure product profitability, they usually start with Gross Margin. The calculation seems straightforward: you take the selling price and subtract the Cost of Goods Sold (COGS), which typically just means the manufacturing or purchasing cost.

If a jacket sells for £100 and costs £30 to make, the Gross Margin looks like a healthy 70%. Based on that number, your marketing team might aggressively push that jacket across every channel, assuming it is a cash cow.

However, Gross Margin ignores the operational reality of eCommerce. It does not account for the variable costs incurred the moment a customer clicks "buy." To understand if a product is actually making you money, you must calculate its Contribution Margin.

Contribution Margin Explained

Contribution margin measures the profit a specific product generates after deducting all the variable costs associated with selling and fulfilling that exact item.

To find the true contribution margin of a SKU, you must subtract the following from the selling price:

• COGS: The landed cost of the item.
• Pick and Pack Costs: The labour cost of your warehouse team fulfilling the order.
• Packaging: The cost of the box, tape, and inserts required for that item.
• Shipping Costs: The carrier rate based on the item's dimensional weight.
• Channel Fees: The percentage taken by the marketplace (e.g., Amazon, eBay, or Shopify payments).
• Return Rate Costs: The statistical cost of reverse logistics for that specific item category.

When you apply this rigorous calculation, the financial picture often changes drastically.

That £100 jacket with a 70% Gross Margin might be large and heavy, triggering carrier dimensional surcharges. It might be sold on a marketplace with a 15% fee, and it might require bespoke packaging. Once you deduct the £15 channel fee, the £12 shipping cost, and the £4 pick-and-pack fee, the true contribution margin plummets.

If you don't track these metrics at the SKU level, you will inevitably scale the wrong products.

Uncovering the Hidden Losers

When you lack visibility into contribution margins, two dangerous scenarios play out in your back office.

1. The High-Volume Loser: You have a product that sells incredibly well on Amazon. The volume is huge, so you keep reordering massive quantities. But because you aren't tracking the specific fulfilment and marketplace fees against the SKU, you don't realise the contribution margin is actually negative. You are effectively paying customers to take the product off your hands, and the high sales volume is simply accelerating your cash burn.

2. The Channel Imbalance: A product might be highly profitable when sold directly through your Shopify site, but a loss leader when sold wholesale due to steep discount tiers and freight costs. Without channel-level margin analysis, you might inadvertently push inventory toward the least profitable sales channel, starving your own high-margin DTC site of stock.

To stop the bleeding, you need a system that tracks these costs dynamically.

Building the Right Data Architecture

The reason most brands fail to track contribution margin is that the necessary data is fractured. The COGS lives in an accounting tool, the channel fees are stuck in the marketplace dashboard, and the shipping costs are locked in a carrier portal.

Attempting to export all this data and merge it in Excel at the end of the month is an administrative nightmare. By the time the finance team identifies an unprofitable SKU, you have already spent weeks aggressively marketing it.

To solve this, you must centralise your operational data. You need a Retail-First ERP that acts as a single source of truth, pulling in revenue, fees, and fulfilment costs in real-time.

This is exactly how Brightpearl by Sage provides a strategic advantage. As a Retail-First ERP designed specifically for omnichannel merchants, it natively handles your inventory, orders, and fulfilment routing, meaning it already knows the exact cost of every action in your warehouse.

Because all this data lives in one central hub, Brightpearl offers Retail Analytics as a built-in feature. Instead of relying on delayed spreadsheets, the Retail Analytics engine instantly calculates your true SKU-level and channel-level profitability. 

It cross-references your landed COGS with live shipping rates and marketplace fees, giving you a clear dashboard that highlights exactly which products are generating cash and which are silently draining your margins.

By securing real-time visibility into your contribution margins, you can stop guessing, confidently pause unprofitable campaigns, and direct your capital only toward the items that actually grow your business.

Ready to stop flying blind on profitability?

Discover how the Retail Analytics feature inside Brightpearl by Sage can reveal the true margins of your catalogue. Book a demo today.