This guide is for US sellers using Fulfillment by Amazon who want to know what a unit really earns after Amazon's cut, whether for a supplier's sample or a listing that already sells.
It builds net proceeds, profit, margin and ROI step by step, explains why margin and ROI can disagree, finds a break-even price, and tests a price under $10 and a slightly smaller box. Fees follow Amazon's 2026 US rate card as we checked it on October 8, 2026; its peak and storage rates were checked once more on October 15, 2026.
How FBA profit is calculated
Five formulas, each feeding the next:
Amazon fees = fulfillment fee + referral fee + closing fee (media only) + storage + placement fee
Net proceeds = selling price − Amazon fees
Profit = net proceeds − landed cost − inbound shipping
Margin = profit ÷ selling price
ROI = profit ÷ (landed cost + inbound shipping)
Selling price
What the buyer pays. The referral fee is a percentage of it, and it sets the price band for the fulfillment fee: Amazon's 2026 rates have three bands, under $10, $10 to $50 inclusive, and over $50.
Fulfillment fee
The charge to pick, pack and ship one unit, set by size tier, shipping-weight bracket, price band and season under the rate card effective January 15, 2026. Amazon bills whichever is heavier, the scale weight or the dimensional weight (the box's cubic inches ÷ 139), except for small standard and extra-large units over 150 lb, which use scale weight. A 3.5% fuel and logistics surcharge sits on top for units shipped on or after April 17, 2026, and orders that ship to the buyer from October 15, 2026 through January 14, 2027 pay the holiday peak rates. The season is set by the date the order leaves Amazon's warehouse, not the date your stock arrived there. The tiers are covered in Amazon FBA fees explained.
Referral fee
Amazon's commission, set by category in its referral fee schedule. Most categories, including home and kitchen, toys, sports and office products, pay 15% of the sale price with a $0.30 minimum per unit. Beauty and baby items pay 8% at $10 or less, and consumer electronics pays 8%. Media categories (books, music, video and DVD, software, and video games) also add a $1.80 closing fee to every item sold.
Storage
Amazon bills monthly storage by the cubic foot. Standard-size units pay $0.78 per cubic foot from January to September and $2.40 from October to December; oversize units pay $0.56 and $1.40. The per-unit cost is cubic feet × each month's rate, added up over the months on the shelf, with a part month counted by its days.
Placement fee
The inbound placement fee is zero when Amazon chooses how to split your shipment across its warehouses and a per-unit charge when you ask for fewer destinations. Use whatever your shipment plan shows.
Landed cost and inbound shipping
Landed cost is the factory price plus freight, duty, inspection and prep for one sellable unit. Inbound shipping is the cost of moving that unit into an Amazon warehouse, divided across the shipment. Together they are the cash tied up per unit, and the ROI denominator.
Three worked examples
All three use a 20 oz insulated tumbler listed in Home & Kitchen (15% referral) that weighs 0.9 lb packed. Each order ships to the buyer on June 1, 2026, a non-peak date, after two months in storage at the January–September rate. Landed cost is $5.40 and inbound shipping $0.55 per unit. Every figure is the output of the Amazon FBA calculator's own math.
Example 1: $22.99, packed 9 × 4 × 4 inches
- The box is too thick for small standard but sits inside the large standard limits of 18 × 14 × 8 inches and 20 lb.
- Its dimensional weight, 9 × 4 × 4 ÷ 139, is 1.04 lb. That outweighs the tumbler itself, so Amazon bills 1.04 lb and prices it from the 1+ to 1.25 lb bracket instead of the 12+ to 16 oz bracket its scale weight would earn.
- Non-peak rate in the $10–$50 band: $5.04. Surcharge: $0.18. Fulfillment fee: $5.22.
- Referral fee: 15% of $22.99 = $3.45.
- Storage: 0.0833 ft³ × $0.78 × 2 months = $0.13.
- Amazon fees total $8.80, leaving net proceeds of $14.19.
- Profit: $14.19 − $5.40 − $0.55 = $8.24.
- Margin: $8.24 ÷ $22.99 = 35.84%. ROI: $8.24 ÷ $5.95 = 138.49%.
Example 2: the same tumbler at $9.99
At $9.99 the unit drops into the lowest price band: a $4.22 rate plus a $0.15 surcharge, so the fulfillment fee is $4.37. The referral fee is 15% of $9.99 = $1.50; the $0.30 minimum only takes over below $2.00. Storage stays at $0.13.
Amazon fees come to $6.00 and net proceeds to $3.99. After $5.40 landed and $0.55 inbound, profit is −$1.96: a margin of −19.62% and an ROI of −32.94%.
The price fell by $13.00, but fees fell by only $2.80 ($0.85 of fulfillment, $1.95 of referral), so profit fell by $10.20, and fees went from 38.28% of the price to 60.06%. The cheaper band cannot rescue a price below fixed costs.
Example 3: $22.99, packed 8.5 × 3.75 × 3.75 inches
Taking half an inch off the length and a quarter inch off the other two sides cuts dimensional weight to 8.5 × 3.75 × 3.75 ÷ 139 = 0.86 lb, now lighter than the tumbler. The billed weight becomes the 0.90 lb unit weight, in the 12+ to 16 oz bracket: $4.60 plus a $0.16 surcharge, for $4.76. The 0.0692 ft³ box costs $0.11 to store for two months. Referral stays at $3.45.
Amazon fees are $8.32, net proceeds $14.67 and profit $8.72, a 37.93% margin and a 146.55% ROI. Packaging alone added $0.48 per unit ($0.46 of fulfillment, $0.02 of storage), or $480 across 1,000 units. A smaller box still would not lower the fulfillment fee, because unit weight now sets the bracket; it would only trim storage by a few cents. At 8 × 3.5 × 3.5 inches, storage drops to $0.09 and profit rises to $8.74.
| Per unit | Example 1 | Example 2 | Example 3 |
|---|---|---|---|
| Selling price | $22.99 | $9.99 | $22.99 |
| Billed shipping weight | 1.04 lb | 1.04 lb | 0.90 lb |
| Fulfillment fee with surcharge | $5.22 | $4.37 | $4.76 |
| Referral fee | $3.45 | $1.50 | $3.45 |
| Storage, 2 months | $0.13 | $0.13 | $0.11 |
| Amazon fees | $8.80 | $6.00 | $8.32 |
| Net proceeds | $14.19 | $3.99 | $14.67 |
| Profit | $8.24 | −$1.96 | $8.72 |
| Margin | 35.84% | −19.62% | 37.93% |
| ROI | 138.49% | −32.94% | 146.55% |
The calendar matters too, and it is the sale that counts. Suppose example 1's tumblers sell and ship inside the October 15 – January 14 window, on December 20, 2026, after two months in stock. The peak rate of $5.34 plus a $0.19 surcharge makes fulfillment $5.53, and two months at the October–December storage rate of $2.40 per cubic foot cost $0.40. Fees climb to $9.38 and profit slips to $7.66, a 33.32% margin and a 128.74% ROI. The peak fulfillment rate applies however early the stock went in.
Why margin and ROI disagree
Both start from profit but divide it by different things. Margin asks how much of each sales dollar you keep; ROI asks how hard each dollar of inventory cash works. One identity connects them:
ROI = margin × selling price ÷ (landed cost + inbound shipping)
Stock that is cheap relative to its price earns a high ROI even at a modest margin. Compare example 1 with a $79.99 product in a 9 × 6 × 2 inch box at 0.8 lb, costing $28.00 landed and $0.50 inbound, same category and ship date.
| Per unit | Product A (example 1) | Product B |
|---|---|---|
| Selling price | $22.99 | $79.99 |
| Amazon fees | $8.80 | $17.13 |
| Profit | $8.24 | $34.36 |
| Margin | 35.84% | 42.96% |
| ROI | 138.49% | 120.56% |
| Units $1,000 of inventory buys | 168 | 35 |
| Profit on those units | $1,384.32 | $1,202.60 |
B wins on margin and profit per sale; A wins on ROI and returns more per $1,000 of stock, if each $1,000 of stock sells through in the same time. When cash is the constraint, rank by ROI. When ads and returns run heavy, lean on margin: it shows how much room each sale has to absorb them.
Finding your break-even price
Break-even is the price at which profit is exactly zero. Inside one price band, and above the $0.30 referral minimum, it can be solved directly:
Break-even price = (fulfillment fee + closing fee + storage + placement fee + landed cost + inbound shipping) ÷ (1 − referral rate)
The answer holds only if it lands in the price band you assumed. In the calculator, the original 9 × 4 × 4 inch package breaks even at $13.29 (one cent lower it loses $0.01) and the 8.5 × 3.75 × 3.75 inch package at $12.73. Neither breaks even under $10: at $9.99 the 9 × 4 × 4 package still loses $1.96 and the smaller one loses $1.48. Or simply lower the price in the FBA calculator until profit reads zero.
Common mistakes
- Costing the product instead of the package. Tiers and dimensional weight follow the packed unit. In its 9 × 4 × 4 box the 0.9 lb tumbler is billed at 1.04 lb, which costs $0.46 more in fulfillment than the tighter box in example 3.
- Entering the factory price as product cost. Landed cost includes freight, duty and prep. Suppose, for illustration, that $1.40 of the tumbler's $5.40 is freight and duty: entering $4.00 shows a profit of $9.64 and an ROI of 211.87%, when the real figures are $8.24 and 138.49%.
- Calling ROI margin. 138.49% and 35.84% describe one unit; swap them and a thin product looks rich.
- Treating net proceeds as profit. The $14.19 left after Amazon's fees in example 1 still has to cover $5.95 of landed cost and inbound shipping before $8.24 remains.
- Pricing holiday sales off a summer fee sheet. Peak fulfillment rates follow the date an order ships to the buyer, and standard storage rises from $0.78 to $2.40 per cubic foot in October. The same tumbler earns $7.66 instead of $8.24 on a December 20 sale.
- Expecting the under-$10 band to protect margin. In example 2 it saved $0.85 of fulfillment while the price fell $13.00.
When the calculator is enough, and when it is not
By hand is fine once a listing exists and Seller Central shows its fees: subtract them and your costs from the price, then divide.
Use the calculator when working from the packaged unit's dimensions and weight as a supplier quotes them, comparing box sizes, testing a price near $10 or $50, or planning for the holiday window. Looking up tier, weight bracket, band and season by hand is easy to get wrong, and each step of the result is shown.
It is not a full profit-and-loss statement. It leaves out:
- Advertising. Divide a month's ad spend by that month's unit sales and treat it as a per-unit cost.
- Returns, including refunds and units that cannot be resold.
- The low-inventory-level fee, which depends on stock held relative to sales.
- Storage utilization and aged-inventory surcharges on slow-moving stock.
- The Professional selling plan, $39.99 per month: $0.80 per unit at 50 units a month, $0.40 at 100, $0.08 at 500.
Take example 1 and assume, for illustration, $1.50 of advertising per unit and 100 units a month sharing the plan at $0.40 each. Profit falls from $8.24 to $6.34, margin from 35.84% to 27.58%, and ROI on the $5.95 of inventory cash from 138.49% to 106.55%.
Once a product is selling, the fees Seller Central reports for it outrank any estimate, this one included. If you also sell on Etsy, its fees work differently; see Etsy fees explained.
Sources
Every rate and rule in this guide comes from these official pages; the dates are when we last checked them.
Run your own numbers
More guides
Note. Guides explain how the numbers work using published rules and our own worked examples. They are not tax, legal, financial or engineering advice; fees and codes change, so check the current source before you rely on a figure.