An Amazon FBA calculator subtracts the referral fee, the FBA fulfillment fee, advertising, storage and returns from your selling price, along with your landed product cost, to show net profit per unit. Amazon sets the FBA fee by size tier and shipping weight, so the package dimensions matter as much as the price.
How does this Amazon FBA calculator work?
Every number is computed in your browser from the inputs above. Nothing is sent anywhere unless you choose to unlock the full report. These are the formulas it uses:
- Referral fee = price × the category rate (tiered where the category is tiered), with a $0.30 minimum for most categories.
- FBA fee = the fee for your size tier and shipping weight, adjusted for the price band (lower under $10, higher over $50). Your override replaces it entirely.
- PPC cost = price × target TACoS.
- Storage = cubic feet × monthly rate × months stored, or your override.
- Returns = price × returns allowance %.
- Net profit = price − product cost − shipping to Amazon − referral − FBA − PPC − storage − returns.
- Net margin = net profit ÷ price. ROI = net profit ÷ (product cost + shipping to Amazon).
- Break-even ACoS = profit before advertising ÷ price. Max CPC = profit before advertising × conversion rate.
What FBA fee assumptions does it use?
The size tier comes from your sorted dimensions (longest, median, shortest) and weight. Small standard items are charged on unit weight. Everything larger is charged on shipping weight: the greater of unit weight and dimensional weight, where dimensional weight = L × W × H ÷ 139. For bulky items, width and height are treated as at least 2 inches. Fees below are the $10–$50 price band of the US non-apparel table. Last reviewed September 2026.
| Size tier | Max dimensions (in) | Max weight | Estimated FBA fee |
|---|---|---|---|
| Small standard | 15 × 12 × 0.75 | 16 oz (unit) | $3.06 (≤2 oz) to $3.65 (14–16 oz), in 2 oz steps |
| Large standard | 18 × 14 × 8 | 20 lb (shipping) | $3.68 (≤4 oz) to $6.62 (2.75–3 lb), then $6.92 + $0.08 per 4 oz above 3 lb |
| Small bulky | 37 × 28 × 20; length + girth ≤ 130 | 50 lb | $9.61 + $0.38/lb above the first lb |
| Large bulky | 59 × 33 × 33; length + girth ≤ 130 | 50 lb | $9.61 + $0.38/lb above the first lb |
| Extra-large | Anything larger | — | From $26.33 (0–50 lb) upward in weight bands |
Items priced under $10 get the low-price rate, which we model as $0.77 less for standard sizes. Items over $50 carry a higher fee, which we model as a flat surcharge you can edit under Advanced assumptions. Storage defaults to Amazon's off-peak standard rate of $0.78 per cubic foot per month ($0.56 for bulky); the October to December peak rate is roughly three times higher, so raise the months or override the number if you sell into Q4. Amazon revises these tables, so treat every figure as an estimate and use the override when you know the real fee.
How are Amazon referral fees calculated?
Most categories pay 15% of the total sale price. The exceptions built into the dropdown: Beauty, Health & Personal Care and Baby pay 8% at $10 or less and 15% above; Grocery pays 8% at $15 or less; Clothing pays 5% up to $15, 10% from $15 to $20 and 17% above; Consumer Electronics pays 8%, Personal Computers 6%, Automotive and Industrial 12%, and Amazon Device Accessories 45%. Electronics Accessories, Furniture and Jewelry charge a lower rate only on the portion of the price above a threshold. These are estimates; check Amazon's current referral fee page for your exact category.
How should you read the results?
The verdict pill uses net margin after every cost in the model:
| Net margin | Verdict | What it usually means |
|---|---|---|
| 20% or more | Healthy | Room to absorb a price war, fee change or heavier launch spend. |
| 10% to 20% | Thin | Works if ads are efficient and inventory turns fast. Little slack. |
| Under 10% | Risky | One bad month of ads, returns or storage can wipe out profit. |
Break-even ACoS is the most useful number for advertising. Any campaign running above it loses money on each ad-attributed sale. Your target TACoS sits across all sales, so it should be well below break-even ACoS. For a deeper playbook, read how to lower your Amazon ACoS without killing sales.
What mistakes make FBA products look more profitable than they are?
- Using factory price instead of landed cost. Freight, duty, inspection and prep belong in product cost.
- Ignoring dimensional weight. A lightweight product in an oversized box pays for the box. Half an inch can move you into a higher tier.
- Leaving out advertising. A private-label product with zero ad spend is rare. Model a realistic TACoS, especially at launch.
- Forgetting storage and Q4. Slow sellers and peak-season storage quietly eat margin. See our Amazon inventory management guide.
- Assuming FBA is always right. Heavy, slow or bulky items can be cheaper to fulfill yourself. Compare in FBA vs FBM for private label.
Embarc Consulting is an SPN-registered, private-label-only Amazon agency. We run this math every week for the brands we manage, alongside ad audits toward target ACoS. If your numbers look thin, Amazon PPC management and full account management are where Embarc Consulting usually starts.