Amazon revenue can rise while profit falls because a larger share of sales is coming from lower-margin products. Even if every SKU keeps the same price, costs and margin, the account’s blended margin can decline. Before changing bids or prices across the catalogue, separate a change in what you sold from a change in what each product earns.
The distinction matters because the response is different. Higher fees need a cost review. A weaker product mix may need a closer look at stock availability, promotions and where your growth is coming from.
What is sales mix on Amazon?
Sales mix is the proportion of total sales generated by each product. For a margin analysis, measure that proportion in revenue, not units. A $50 product and a $10 product do not carry the same weight in the account’s revenue. This measures revenue-share mix, so price changes and refunds can change the mix even when unit sales do not.
Revenue share of a SKU = SKU revenue ÷ Total revenue
Blended product margin = Sum of (Each SKU’s revenue share × Its product margin)
Throughout this article, revenue means net revenue after discounts and refunds. Product margin = product profit ÷ net revenue. Product profit means that net revenue less landed COGS, Amazon charges, advertising and other costs assigned to the product. Shared overhead is kept separate. This is a management-analysis measure before shared overhead, interest and tax.
If your starting report already includes overhead in product profit, remove that allocation before using this method, or keep it included throughout and do not subtract it again.
How can sales grow while profit falls?
Consider two products with unchanged economics. Product A sells for $30 and earns $9 per unit before shared overhead, a 30% product margin. Product B sells for $20 and earns $2, a 10% margin.
The figures below are illustrative. Each period is the same length, with no discounts or refunds in the example. The per-unit profit figures already include all assigned product costs.
| Metric | Previous period | Current period |
|---|---|---|
| A units sold | 1,000 | 700 |
| A revenue | $30,000 | $21,000 |
| A product profit | $9,000 | $6,300 |
| B units sold | 1,000 | 2,000 |
| B revenue | $20,000 | $40,000 |
| B product profit | $2,000 | $4,000 |
| Total revenue | $50,000 | $61,000 |
| Total product profit | $11,000 | $10,300 |
| Blended product margin | 22.0% | 16.9% |
Product B doubled its unit sales, adding $20,000 in revenue and $2,000 in product profit. Product A lost 300 units, reducing revenue by $9,000 and product profit by $2,700. Total revenue rose by $11,000, but product profit fell by $700.
The business did not become less profitable because either SKU’s margin deteriorated. The lower-margin SKU became a much larger part of the sales mix.
With unchanged shared overhead of $5,000 per period, operating profit before interest and tax falls from $6,000 to $5,300. That is a 12% decline, rounded, alongside 22% revenue growth.
Why is an average of SKU margins misleading?
A simple average of 30% and 10% is 20%. That would report the same margin in both periods and miss the entire change.
In the first period, A generated 60% of revenue and B generated 40%:
(60% × 30%) + (40% × 10%) = 22.0% blended product margin
In the second period, A generated approximately 34.4% of revenue and B generated 65.6%:
(34.4% × 30%) + (65.6% × 10%) ≈ 16.9% blended product margin
The blended margin fell by approximately 5.1 percentage points while both individual product margins stayed unchanged. Calculate the account ratio from total product profit divided by total revenue, or use revenue-weighted SKU margins. Both should give the same result.
How do you separate the mix effect from a margin change?
Real accounts can have both at once: the catalogue shifts toward lower-margin products while fees, advertising or returns also change. A simple spreadsheet can separate the two effects.
1. Build a consistent comparison.
Use two equal periods, the same marketplace and currency, and the same cost treatment. For each SKU, record revenue and product profit in both periods, then calculate revenue share and product margin. Check COGS completeness and late-posted costs before interpreting a recent period.
2. Apply the old margins to the current mix.
Mix-only margin = Sum of (Current revenue share × Previous product margin)
This asks what the account margin would be with today’s revenue mix if each SKU still earned its previous margin. It is a calculation for diagnosis, not a forecast that those margins can be maintained.
3. Split the change in percentage points.
Mix effect = Mix-only margin − Previous blended margin
Within-SKU margin effect = Current blended margin − Mix-only margin
Together, these two effects reconcile to the total change in blended product margin. In the worked example, the mix effect is about −5.1 percentage points and the within-SKU margin effect is zero.
If the current blended margin were instead 15.9%, the same comparison would show about −5.1 points from mix and another −1.0 point from changes inside the SKUs. You would investigate both product demand and product costs.
Analyze new products, exits and SKUs with zero or negative net revenue separately, including refund-only periods. For the remaining comparable SKUs, recalculate each period’s revenue shares within that group. The two effects then reconcile that group’s margin change. Reconcile the excluded products’ revenue and profit separately back to account totals; do not fill a missing historical margin with zero.
What should you check when the mix moves?
Start with the products whose revenue share changed most, then investigate what changed operationally.
| What changed | What to investigate |
|---|---|
| Higher-margin products lost revenue share | Stockouts, availability, Featured Offer share, seasonality or weaker demand |
| Lower-margin products gained share | Promotions, ad-budget allocation, new variations or changes in customer demand |
| Mix was stable but SKU margins fell | Prices, landed COGS, Amazon charges, advertising and return-related costs |
| Product profit was stable but operating profit fell | Shared overhead and the consistency of cost allocations |
These are possible explanations to test, not conclusions from the margin calculation alone. A change in revenue share does not prove that a stockout, campaign or competitor caused it.
Also keep returns and timing in view. A product with rising refunds can show a lower margin as well as a smaller share of net revenue. Do not subtract refunded revenue twice, once in revenue and again as a separate cost. Additional return-related fees and inventory losses still need to be included.
Should you stop selling a lower-margin product?
A lower percentage margin is not, by itself, a reason to stop selling a product. If it adds profit without displacing more valuable sales or consuming scarce capacity, it may still improve the business.
In the example, B’s growth added $2,000 of product profit. Stopping it would not recover A’s lost $2,700. The useful questions are why A declined and whether B’s growth uses inventory capital, advertising budget or fulfillment capacity that could earn more elsewhere.
Check profit dollars, stock turnover and cash requirements alongside margin. Avoid using an allocated share of fixed overhead as if it would disappear when you remove a SKU.
Best practices
- Review revenue share, product margin and product profit dollars together for the SKUs driving the change.
- Use revenue-weighted margins and reconcile them to account totals.
- Keep shared overhead separate so an allocation change does not look like a product-cost change.
- Split mix changes from within-SKU margin changes before changing prices or ad budgets.
- Check stock availability, promotions and seasonal demand on the products losing share.
- Repeat the calculation at variation level when sizes, colours or pack counts have materially different economics.
Common mistakes
- Averaging SKU margin percentages without weighting them by revenue.
- Blaming fees or PPC immediately when individual product margins have not changed.
- Treating a lower blended margin as proof that total profit also fell. More volume can outweigh a lower margin; check both.
- Comparing markets or currencies together before checking whether the mix of those markets changed.
- Treating missing COGS, new products or late refunds as comparable historical data.
- Cutting a lower-margin SKU without checking the profit dollars it adds and the costs that would actually be saved.
FAQ
Why is my Amazon profit down when revenue is up?
Possible causes include lower product margins, a shift toward lower-margin products, higher shared overhead, or a combination. Compare SKU revenue shares and margins first, then reconcile the product-profit change to the account P&L.
What is the sales mix effect?
It is the change in blended margin caused by changes in the share of revenue each product contributes. The effect can be negative even when every SKU’s individual margin remains stable.
Should I weight profit margins by units or revenue?
By revenue when calculating a blended margin percentage. Use units to calculate average profit per unit, which answers a different question.
Can a lower-margin product still be worth scaling?
Yes. Evaluate the additional profit dollars and the capital, stock and operating capacity required. A lower percentage margin can still produce an attractive result if the additional sales are profitable and do not crowd out a better use of constrained resources.
Can sellerboard help with this analysis?
sellerboard shows product-level sales, costs and profitability, supports product and KPI trend analysis, and lets you export data into spreadsheets. Those figures can support a sales-mix calculation after you make the cost definitions consistent.
Conclusion
When revenue and profit move in opposite directions, check what changed in the catalogue before applying an account-wide fix. A revenue-weighted comparison shows whether margin moved because individual products earned less or because lower-margin products made up more of the sales. Then connect that result to stock, advertising, pricing and demand, and judge the response by the profit dollars it can recover.
