Amazon FBA Fee Calculator

Worked Example: Why a 12 oz Box Is Billed as 27.6 oz

These are the calculator's default inputs: a $29.99 product in Home and Kitchen (15% referral fee), costing $10.00 to make and $1.50 to ship to Amazon, in a 10" × 6" × 4" box weighing 12 oz, stored during January to September.

1. Size tier. The shortest side is 4", which is over the 0.75" small standard limit, so the item is Large Standard.
2. Dimensional weight. 10 × 6 × 4 = 240 cubic inches, and 240 ÷ 139 = 1.73 lb, or 27.6 oz. That is more than the real 12 oz, so the fee uses 27.6 oz.
3. Fulfillment fee. 27.6 oz falls in the 1.5 to 1.75 lb row, and $29.99 is in the $10 to $50 price band, so the fee is $5.89 plus a $0.21 fuel surcharge, which makes $6.10. At the real 12 oz it would have been $4.64.
4. Referral fee. 15% of $29.99 = $4.50.
5. Storage. 240 ÷ 1,728 = 0.139 cubic feet × $0.78 = $0.11 per unit for a month.
6. Profit. $29.99 − $4.50 − $6.10 − $0.11 − $10.00 − $1.50 = $7.78 per unit, a 25.9% margin and a 68% return on the $11.50 product and inbound cost.

The lesson is in step 3. A box that is mostly air costs $1.46 more per sale here than its real weight suggests. Trimming the box to 9" × 6" × 3" (162 cubic inches, 18.6 oz dimensional weight) moves it down to the 1 to 1.25 lb row, which is $5.53 with the surcharge.

Small standard items work differently, because Amazon bills them on their real weight only. A flat 15" × 12" × 0.75" mailer weighing 2 oz has a dimensional weight of 15.5 oz, but at $29.99 it is charged as 2 oz, which is $3.51 plus a $0.12 surcharge, or $3.63.

Which Fees This Uses and What It Leaves Out

• All figures are for the US marketplace and were last checked on October 18, 2026. Referral rates come from Amazon's published 2026 fee table, and fulfillment fees are the rates Amazon's own Revenue Calculator gave on that date.
• October 18 falls inside Amazon's holiday peak period, which runs from October 15, 2026 to January 14, 2027, so the fulfillment fees here are peak rates. Amazon says peak rates are about $0.32 per unit higher on average, so outside that period your real fee will usually be a little lower. Amazon also tends to announce new yearly fees in January, so confirm current rates in Seller Central or the Revenue Calculator before you rely on them.
• Items priced under $10 get Amazon's lower price band automatically, and the calculator applies it. Clothing uses Amazon's separate apparel rates for standard-size items.
• The inbound placement service fee and the low-inventory-level fee are not included. Both depend on how you ship to Amazon and how much stock you keep, so they can't be worked out from one product. Returns processing, removal and disposal, aged inventory and storage utilization surcharges, dangerous goods rates, advertising and sales tax are not included either.
• Storage is shown for one month per unit sold, using the non-dangerous goods rates.

Sources

• Referral fee percentages, minimums and the media closing fee: Amazon, "Standard selling fees", checked October 18, 2026.
• Fulfillment fees by size tier, weight and price band: Amazon FBA Revenue Calculator, checked October 18, 2026.
• Size tiers, the rule that small standard items are billed on unit weight, and monthly storage rates: Amazon Supply Chain Services rate card (October 15, 2026 to January 14, 2027), which states that storage fees are the same as FBA.
• Dimensional weight divisor of 139 and the 2" minimum width and height for bulky and extra-large items: Amazon staff reply on Seller Forums, quoting the Seller Central help page.
• 2026 fee update, peak period and fuel surcharge: Amazon announcements on Seller Forums for the 2026 US fee changes (effective January 15, 2026), holiday 2026 peak fees and the 3.5% fuel and logistics surcharge (from April 17, 2026).

Figures are estimates for planning, not financial advice. Check your numbers with Amazon's own Revenue Calculator in Seller Central before you list. See our disclaimer.