Net Profit Calculator

A lot of new sellers answer "how much do you make?" with the sale price minus what they paid for the product. That number is wrong, and the gap between it and reality is where businesses die quietly.

Amazon takes a slice in three predictable places — the referral fee, the FBA fee, and the cost of the ad you probably ran to make the sale. Miss any one of those and you're planning on money that isn't there.

What goes in

• Sale price — what the customer paid, before any promotions you ran.
• Referral fee — a percentage of the sale, by category. 15% covers most of what people sell; check yours, because things like Amazon Devices or some jewelry categories are higher.
• FBA fee — use the FBA Fee Calculator on this site for an accurate number rather than a guess.
• COGS — your product cost. Whether you include freight here or in "other" doesn't matter as long as you count it once.
• PPC per sale — this is the one people forget. If you spend $30 to get 10 sales, that's $3 per order. On a $20 product that's 15 points of margin gone.

Reading the result

The table shows the math line by line so you can see which cost is doing the damage. If FBA is huge, the product is too bulky. If PPC is huge, your targeting or your conversion rate is the problem, not the product. If COGS is huge, the supplier negotiation or the product choice is the problem.

A rule I use: below 10% net margin on a cheap item, you have almost no room for anything to go wrong — a fee bump, a return spike, a PPC increase — and any one of those turns the product red. Most private-label products that are worth keeping run 20–35% net. If you're consistently under that, something in the chain needs fixing before you scale spend.

This is profit per unit. It doesn't include your monthly software bill, VA, or the sample orders that didn't work out. Those are real, but they're fixed costs spread across volume — worth a separate look once you know the per-unit number is healthy.