FBA fee calculator FAQ: referral, fulfillment, storage, low-inventory-level and aged inventory fees in 2026, how they are calculated per FNSKU, and how accurate the estimates are.
What FBA fees does Amazon charge in 2026?
Five main buckets: 1) referral fee — about 8%-45% of the sale price by category (15% in most); 2) FBA fulfillment fee — per unit, based on size tier and weight; 3) monthly storage — per cubic foot, with higher rates October-December; 4) aged inventory surcharge for units stored 181+ days; 5) optional inbound placement and low-inventory fees. Our calculator models all of them from a single product input.
How is the referral fee calculated?
The referral fee is a percentage of total sales price (including shipping charged to the customer). Most categories sit at 15%; a few differ — for example grocery at 8% under $100 and 15% above, jewelry at 20%, and Amazon device accessories up to 45%. There is a $0.30 minimum per item on most categories.
How are FBA fulfillment fees determined?
Fees depend on the size tier (small standard, large standard, small oversize, large oversize) and weight band, which Amazon derives from the packaged dimensions and weight. That is why dimensional weight matters: a small packaging change can drop you a tier and save more than $1 per unit. The calculator shows which tier your product falls into and how close you are to the boundary.
What are the storage fees, and when do they peak?
Monthly storage is charged per cubic foot. Off-peak (January-September) is roughly $0.78/cu ft for standard size; peak months (October-December) rise to about $2.40/cu ft. Units stored over 181 days (or 365 days depending on program) trigger additional aged inventory surcharges. Plan Q4 inventory carefully — peak storage is the silent margin killer.
How accurate are the calculator's estimates?
The calculator uses Amazon's published 2026 fee card and standard size-tier tables, so referral and fulfillment estimates are typically exact. Actual fees can differ if Amazon re-measures your package, so always verify tier classification in Seller Central after your first inbound shipment.
Is the low-inventory-level fee charged per parent ASIN or per FNSKU?
Per FNSKU. Since January 15, 2026 Amazon measures days of supply for every child SKU on its own instead of averaging the parent ASIN, so a single thin variation bills the fee even when the parent looks healthy. The fee fires only when BOTH the trailing 30-day and the trailing 90-day days of supply sit below 28 days, and the rate band is taken from the HIGHER of the two windows. Rates run $0.32-$2.09 per shipped unit by size tier: standard size $0.32-$1.11, Small and Large Bulky $0.51-$2.09; Extra-Large tiers sit outside the fee. A window with no shipped units leaves days of supply undefined, which Amazon treats as above 28 days, so nothing is charged. Source: Seller Central help page GV43F6S76Y9DHYRH, verified 2026-09-15. The fee calculator scores each child SKU on its own row so a variation cannot hide inside the parent average.
