Profit intelligence

What if your best-selling product
is the one killing
your business?

Your top SKU by volume might have the worst margin in your catalogue. Shopify will never tell you. Because it doesn't know your COGS.

Topic SKU profitability
Published July 2026
The question nobody asks

Revenue ranking and profit ranking are almost never the same list.

Every DTC founder knows their best seller. It's the product they reorder first, the one they feature in ads, the one they lead with on their homepage. It's the product that moves the most units and generates the most revenue.

But here's a question most founders have never answered with real data: is that product actually making you money?

Because volume and profit are two completely different things. A product that sells 500 units a month at 20% margin generates less actual cash than a product that sells 80 units at 65% margin. And if you're pouring ad spend into the first one to keep those 500 units moving, the margin might be even thinner than you think.

Two products. Same catalogue. Very different economics.
Product A. "Best seller" Product B. "Slow mover"
Price £38 £54
COGS £19.50 £14.80
Gross margin 49% 73%
Monthly units 480 85
Monthly revenue £18,240 £4,590
Ad spend to sell £5,470 £410 (mostly organic)
Contribution profit £3,406 £2,923
Profit per unit £7.10 £34.39
Illustrative example based on common DTC economics. Your numbers will be different. That's the point.

Product A generates 4× the revenue. In a revenue-first world, it's the hero. It gets the ad budget, the homepage placement, the restock priority.

Product B generates nearly the same profit on a fraction of the sales. It barely needs ad spend because customers find it organically. Each unit sold drops nearly five times more cash into the business.

If you're optimising for revenue, you're doubling down on Product A. If you're optimising for profit, you're asking why Product B doesn't have more variants, more visibility, and more of the budget behind it.

The blind spot
Shopify knows what you sell.
It doesn't know what you keep.
Shopify doesn't store your COGS per SKU. It can't calculate contribution margin per product. It has no concept of ad spend per SKU or profit per order. So its "Top Products" report ranks purely by revenue. Which, in the scenario above, puts the lower-profit product at the top and the higher-profit one at the bottom. Every founder looking at that report is getting a ranking that's potentially the inverse of what actually matters.
How "best seller" bias compounds over time
Ad spend concentrates on high-volume, low-margin SKUs. Because they "move". Squeezing margin further
Inventory capital gets locked into restocking the "hero" product while profitable SKUs sit under-ordered
New product development copies the profile of the best seller (low price, high volume) rather than the quiet earner
Discounting hits the best seller first because "it's the one people know". Destroying the margin that was already thin
The fix

Three things you need to see that Shopify can't show you.

01
Contribution margin per SKU. Not just gross margin
Gross margin (price minus COGS) is only the start. Contribution margin factors in the ad spend required to sell that product, the fulfilment cost, the return rate. A product with 60% gross margin and heavy ad dependency might have a lower contribution margin than a 45% gross-margin product that sells organically. You need the full picture per SKU, not just the first layer.
02
Profit ranking versus revenue ranking. Side by side
Most founders have never seen their product catalogue ranked by actual profit contribution. When you do, the results are almost always surprising. Products you thought were carrying the business turn out to be margin-thin. Products you've been ignoring turn out to be your most efficient earners. The ranking alone changes how you allocate budget, inventory, and attention.
03
Ad spend per SKU mapped to profit per SKU
How much does it actually cost to sell each product? Not at the campaign level. At the product level. When you can see that you're spending £11.40 in ads to generate £7.10 in profit on one product, and £4.80 to generate £34.39 on another, the reallocation decision makes itself. But without this visibility, ad budgets follow revenue, not profitability.

The most dangerous assumption in DTC is that your best-selling product is your most important product. Volume and value are not the same thing. And the gap between them is where most brands quietly bleed cash.

What to do about it

You don't need more data. You need the right data.

e-comProfitAgent connects to your Shopify store and builds the profit picture Shopify can't. Real contribution margin per SKU. True profit ranking alongside revenue ranking. Ad spend efficiency mapped to actual cash generated, not just ROAS.

If you'd like to see what this looks like for your brand specifically, book a 15-minute call with the team. We'll walk through your numbers, show you where the real margin sits in your catalogue, and you'll leave the call knowing which products are building your business and which ones are just making your revenue line look good.

Find out which products are
actually making you money.

Book a 15-minute call. We'll walk through your real numbers. No pitch, just data.

Speak with the team →
15 minutes · No commitment · Your real numbers