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 the General category (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. 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 24 to 32 oz band: $5.69. At the real 12 oz it would have been $4.24.
4. Referral fee. 15% of $29.99 = $4.50.
5. Storage. 240 ÷ 1,728 = 0.139 cubic feet × $0.87 = $0.12 per unit for a month.
6. Profit. $29.99 − $4.50 − $5.69 − $0.12 − $10.00 − $1.50 = $8.18 per unit, a 27.3% margin and 71% return on the $11.50 product and inbound cost.

The lesson is in step 3: a box that is mostly air costs $1.45 more per sale here than its real weight suggests. Trimming the box to 9" × 6" × 3" (162 cubic inches, 18.6 oz dimensional weight) drops it to the $5.40 band.

What This Calculator Leaves Out

• The fee figures are US marketplace rates for non-apparel items and were last updated from Amazon's 2023 to 2024 fee tables. Amazon revises FBA fees at least once a year, so current fees may differ.
• Fees Amazon added in 2024, such as the inbound placement service fee and the low-inventory-level fee, are not included. Neither are returns processing, removal, long-term storage surcharges, advertising or sales tax.
• Referral fees are applied as one flat percentage per category. Several categories really use tiered rates (for example clothing, jewelry and watches change rate at certain price points).
• Storage uses the standard-size monthly rate for every item, including oversize items, which Amazon charges at a lower rate per cubic foot.

Sources

• Referral fee percentages and FBA fulfillment and storage fees: Amazon, "Selling on Amazon fees", US marketplace, with the detailed tables in Seller Central.
• Dimensional weight divisor of 139 and the size tier limits: Amazon Seller Central help pages on product size tiers (US).

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.