Amazon FBA sellers pay three main fee categories in 2026: Referral fees (6–17%) based on category, Fulfillment fees ($3.22–$52.38/unit) based on size tier, and Storage fees ($0.78–$2.40 (Source: Amazon, 2026)/cu ft/month). A standard-size product selling for $25 typically pays $3.75 referral + $4.10 fulfillment = 31% of revenue in Amazon fees alone, before storage. Peak season (Oct–Dec) storage costs triple. Use our FBA Fee Calculator for itemized estimates.