Educational only. Amazon updates fees twice a year — check Seller Central for the current schedule. FBA aggregator math is from Thrasio, Perch, and Boosted Commerce public diligence frameworks.
Seller Central's revenue calculator under-reports your true cost by 8–12 margin points. It covers referral + FBA fulfillment fees but ignores PPC, returns, long-term storage surcharges, and the Q4 peak premium. This guide walks the full P&L for a typical private-label ASIN. Plug your numbers into the Amazon FBA Calculator as you read.
The real fee stack
On a $28 private-label kitchen item with $6.50 COGS:
- Referral fee: $4.20 (15% of $28)
- FBA fulfillment: $4.75 (small standard, ~12 oz)
- Monthly storage: $0.35
- PPC allocation (40% of sales × 22% ACoS): $2.46
- Returns haircut (6% rate): $1.54
- COGS: $6.50
Total deductions: $19.80. Net per unit: $8.20. Net margin: 29%. ROI on COGS: 126%. That's a healthy FBA ASIN.
The 30% rule (and why aggregators enforce it)
Aggregators (Thrasio, Perch, Boosted) won't buy ASINs below ~30% net margin AND ~30% ROI on COGS. If you can't clear both gates, you're working for Amazon, not building equity. The math forces a few choices:
- Differentiate. Me-too products from Alibaba get squeezed by China-direct sellers. You need brand, IP, or formulation.
- Price above $25. The $3.86 FBA fee floor crushes margin on anything cheaper.
- Build off-Amazon traffic. Shopify + email + Meta funnels you control raise enterprise value 2–3×.
PPC ACoS — what's actually healthy
ACoS = Ad Spend ÷ Ad Sales. Target ACoS = (1 − net margin − 5% buffer). For a 29% margin product, anything above ~66% bleeds profit. Stay below ~25% ACoS on launch, then climb as you scale awareness. Below 15% usually means you're under-spending and leaving share on the table.
The hidden cost killers
- Aged inventory: > 271 days = long-term storage fee surcharge ($0.15/cu ft monthly). Plan turns at 4–6×/year.
- Returns to inventory: Customer returns get inspected, often relabeled as "Used" — and many are scrapped at your cost.
- Q4 peak storage: Oct–Dec storage rates triple. Send in only what you'll sell.
- Account suspensions: Listed as a 0% probability, modeled as 100% if it happens. Budget for safety.