Amazon FBA Costs: Fee Lines and Profit Math (2026)

Behind almost every "sales but no profit" complaint on Amazon FBA lies the same cause: half the cost lines were never counted. FBA is an attractive model but not a free one. Here are the FBA costs for 2026, line by line, and the honest profit math.

Main fee lines

• Referral fee: ~15% of the sale price in most categories. Category-dependent; the first line to check.
• FBA fulfillment fee: per order, by size/weight tier — from a few dollars for small-light items, jumping noticeably at each tier boundary.
• Storage fee: monthly, by cubic volume. Notably higher in Q4, with aged-inventory surcharges for stock that sits too long.
• Professional seller account: a flat $39.99/month.

Easily forgotten lines

• Inbound freight: shipping to the warehouse plus customs; per-unit, it materially affects margin.
• Advertising (PPC): 20–40% of revenue at launch — part of the product's real cost, not a "later" line.
• Return costs: Amazon handles returns but bills you; on high-return products it's a silent margin leak.
• Prep/labeling: per-unit fees if you leave prep to Amazon.

Calculating per-unit profit

A simple, honest formula:

Unit profit = sale price − referral − FBA fulfillment − (monthly storage ÷ monthly units) − (inbound freight ÷ batch units) − ad share − product cost − return share

If the result doesn't leave a meaningful positive margin, the product isn't ready for FBA. Our practical threshold: unit cost + inbound freight under ~30% of the sale price.

Size tiers: the most expensive small detail

The fulfillment fee is tiered; one centimeter of packaging can bump a product into the next size tier and jump the per-order fee. Across thousands of orders a year, that's thousands of dollars. Packaging design is a cost decision — target the smallest, lightest pack that stays under the tier boundary.

The takeaway

FBA costs look complex but are manageable: sum referral + fulfillment + storage + the hidden lines (freight, ads, returns) into one formula, optimize the size tier, hold the 30% cost threshold.

Rather than doing the math by hand, use our free Amazon FBA profit calculator: enter your numbers and see net profit, margin, ROI and break-even ACOS instantly. Cross-check exact fees with Amazon's own revenue calculator.

For how FBA works overall see the FBA guide, and for the whole Amazon journey the Amazon guide. To have us run your account with a profit focus, there's Amazon consulting.