Amazon Product Profitability Calculator

How it is calculated

Product profitability is contribution per unit multiplied by units, less any costs attributable to that product but not to the unit: its share of advertising, its storage, its returns, and any product-specific overhead.

The distinction that matters is between per-unit costs, which scale, and product-level costs, which do not. Advertising sits awkwardly between the two and is usually the largest single line.

Profitability at product level is what tells you which listings to keep, restock, promote or drop.

Numbers on it

The $29.99 product at 1,000 units a month: $12.65 of pre-advertising contribution is $12,650. Advertising at $3,000 and returns at $1,100 leaves $8,550 of product contribution.

A second product at $19.99 selling 400 units with $4.10 of contribution generates $1,640, less $900 of advertising and $250 of returns, $490.

The second product is 29% of the first's unit volume and 5.7% of its contribution. It also consumes purchasing attention, warehouse space, a forecast and a restock decision every cycle.

That comparison is the one that drives catalogue decisions, and it is invisible in any view that reports revenue or margin percentage rather than contribution in money.

What it does not tell you

Advertising attribution is genuinely difficult. Amazon reports sales attributed to a campaign within an attribution window, which credits the ad for sales that would have happened anyway and misses halo effects on other products.

Organic and paid sales also interact: advertising drives rank, which drives organic sales, so cutting the advertising on a product frequently costs more than the advertising did.

What follows from it

Rank the catalogue by contribution in money rather than by margin percentage or revenue. The ranking usually surprises people, and the bottom of it is where the attention is being wasted.

Then look at what the bottom quartile costs in attention rather than only in money. A product generating $490 a month that requires the same purchasing and forecasting effort as one generating $8,550 is consuming a resource that is scarcer than capital in most small operations.

Testing whether advertising is incremental

The direct way to find out what advertising is really contributing is to turn it off on a product for a defined period and measure total sales, not attributed sales.

If total sales fall by less than the advertising spend saved, the advertising was not paying. If they fall by more, which happens where advertising was holding rank; it was doing more than the attribution reported.

The test costs a couple of weeks of rank and gives a genuine answer, and it is the only way to resolve the attribution question with data rather than argument. Sellers who never run it tend to either overspend on products that would sell anyway or underspend on ones where the advertising is holding a position they cannot see.

It is worth separating products that acquire customers from products that monetise them. An entry product with thin contribution that reliably leads to a higher-value second purchase is doing a job the contribution ranking cannot see, and cutting it on that ranking alone is a common and expensive mistake.