Amazon FBA Fees Explained: How to Calculate True Profit per Unit
The full fee stack between the price a customer pays and the money that reaches your account, and how to turn it into contribution margin and a break-even ACoS.
To calculate Amazon profit honestly you have to subtract the whole fee stack — not just the referral and fulfillment fees — from the price the customer actually pays. It is common to model those two, treat everything else as overhead, and end up with a spreadsheet margin that never shows up in the bank. This is the structure of that stack as Amazon publishes it for the US in 2026, plus a worked per-unit calculation that ends in contribution margin and break-even ACoS.
One caveat before the numbers: Amazon revises FBA rates most Januaries, so treat the structure below as durable and the exact rates as something you confirm in your own Seller Central fee preview. Everything here reflects the US schedule as of August 2026.
The fee stack between sale price and payout
Amazon documents the fee families below on its own pricing and FBA cost pages. Two are charged on every single order; the rest depend on how you run inventory, which is exactly why they get missed.
| Fee | What triggers it | How it behaves |
|---|---|---|
| Selling plan | Professional account | $39.99/month, fixed — spread across all units |
| Referral fee | Every sale | A category percentage of total price, or a per-item minimum (most categories $0.30), whichever is greater |
| FBA fulfillment fee | Every FBA unit shipped | Per unit, set by size tier and weight; covers pick, pack, ship, customer service and returns handling |
| Fuel and logistics surcharge | Every FBA unit shipped (from April 2026) | A percentage applied on top of the fulfillment fee, not on the sale price |
| Monthly inventory storage | Holding stock | Per cubic foot of daily average volume; higher in the holiday months |
| Aged inventory surcharge | Inventory held 181+ days | Escalating bands by age, on top of base storage |
| Storage utilization surcharge | Holding far more stock than you sell through | Charged on excess volume relative to sell-through, independent of age |
| Inbound placement service fee | Sending a shipment to few receiving locations | Per unit; falls as you split the shipment across more destinations, or use a partnered carrier |
| Returns processing fee | Returns above a category threshold; apparel and shoes on every return | Per returned unit, where Amazon provides free return shipping |
| Low-inventory-level fee | Running thin on days of supply for a fast-moving unit | Per unit, applied while the stock level stays below the threshold |
| Removal / disposal | Pulling or destroying stock | Per unit, at the end of the inventory's life |
Amazon's own referral fee table spans roughly 8% for some categories up to 45% for Amazon device accessories, with media categories carrying an extra per-item closing fee. Most brands in supplements, home, beauty, pet and outdoor land at the common 15%, which is why 15% quietly becomes everyone's mental default — check yours rather than assuming it.
What changed in 2026
Amazon announced that 2026 US FBA fees would rise by an average of roughly $0.08 per unit effective mid-January, with no new fee types introduced — a modest increase after a flat 2025. Then in April, Amazon posted a fuel and logistics-related surcharge of 3.5% applied to fulfillment fees for FBA in the US and Canada, effective April 17, 2026, extended to Multi-Channel Fulfillment and Buy with Prime shortly after. The mechanics matter more than the size: it is a percentage of the fulfillment fee, so it scales with unit weight, not with your price.
Two structural notes worth building into your model. Products priced under $10 fall into Amazon's Low-Price FBA rates, so a price change across the $10 line moves your fulfillment fee, not just your revenue. And Amazon ended its own FBA prep and labeling services in the US at the start of 2026, pushing that cost back to you or your 3PL as a per-unit line rather than an Amazon fee.
The fees that don't arrive per unit
Storage, placement, aged inventory and returns are charged at the account or shipment level, so they never appear on the per-unit view where pricing decisions get made. The fix is boring and effective: allocate them.
Take a rolling three months of those charges from your Seller Central reports, divide by units shipped in the same window, and carry the result as a per-unit line. It will not be exact for any given ASIN, but it is far closer than zero, and it makes the tradeoff visible — an over-ordered SKU carrying five months of cover pays storage and, eventually, an aged-inventory surcharge that a lean SKU does not.
Returns deserve their own line. A returned unit costs you the return processing fee, the fulfillment fee you already paid, and the unit itself if it comes back unsellable — a meaningful haircut on contribution at even a modest return rate.
A worked calculation, per unit
Here is the arithmetic on a standard-size supplement, using assumed inputs so the method is transparent. Substitute your own numbers; the shape is what transfers.
| Line | Assumption | Amount |
|---|---|---|
| Sale price | Listed price | $34.95 |
| Referral fee | 15% of price | −$5.24 |
| FBA fulfillment fee | Standard size, ~1 lb | −$6.15 |
| Fuel and logistics surcharge | 3.5% of fulfillment fee | −$0.22 |
| Allocated storage | 3-month average per unit | −$0.18 |
| Allocated placement, aged, returns | 3-month average per unit | −$0.35 |
| Landed product cost | Manufacturing + inbound freight | −$10.50 |
| Prep and labeling | Per unit at the 3PL | −$1.20 |
| Contribution margin | Before advertising | $11.11 |
That is $11.11 on a $34.95 sale, or 31.8% of price. This is the number that should govern pricing, promotions and ad bids — not gross margin over product cost, which in this example would have read closer to 70% and told you nothing useful.
From contribution margin to break-even ACoS
Contribution margin is what advertising has to spend out of. Turning it into an ad target is one division:
| Metric | Formula | This example |
|---|---|---|
| Contribution margin % | Contribution margin ÷ sale price | 31.8% |
| Break-even ACoS | Same figure — the point where ads consume all contribution | 31.8% |
| Target ACoS for a 12% net margin | (Contribution − target profit) ÷ sale price | 19.8% |
So on this unit, advertising at a 31.8% ACoS breaks even, and anything above it is bought revenue rather than profit. If the goal is a 12% net margin on the sale, the ceiling is roughly 20%. If you want the full treatment of the metric itself — what a good ACoS is, and the three ways teams misread it — that is covered in what ACoS on Amazon actually means; the relationship between ad spend and total revenue sits in TACoS as a growth metric.
Two things this unlocks. Bids stop being a matter of taste: a keyword converting at a CPC that implies 45% ACoS on a unit with a 31.8% break-even is a decision, not an accident. And a launch or defensive campaign run deliberately above break-even becomes a budgeted investment rather than a leak. That discipline is most of what happened in our outdoor brand's ACoS reduction, where ACoS fell from 44% to 21% while the account grew 68% — by cutting spend that was never going to clear the margin, not by bidding lower everywhere.
Unit economics also set the order of operations for growth. Price, cost and fee position gate every other lever, which is why they come first in the six levers that move Amazon revenue, and why unit-level P&L is a standing part of full account management rather than a quarterly exercise.
FAQ
How much does Amazon take per sale?
On an FBA sale Amazon takes a category referral fee — commonly 15%, ranging from about 8% to 45% depending on category — plus a per-unit fulfillment fee based on size and weight, plus a fuel surcharge on that fulfillment fee. Storage, placement, returns and aged-inventory charges are billed separately and are easy to overlook.
How do I calculate break-even ACoS?
Divide contribution margin per unit by the sale price. Contribution margin is the sale price minus referral fee, fulfillment fee and surcharge, allocated storage and returns costs, landed product cost and prep. The resulting percentage is the ACoS at which advertising consumes all profit on that unit — your ceiling, not your target.
Do Amazon FBA fees change every year?
Usually, yes. Amazon revises the US FBA schedule most Januaries and can add surcharges mid-year, as it did with the 3.5% fuel and logistics surcharge on fulfillment fees in April 2026. Rebuild your unit economics after each announcement, because a per-unit change of a few cents moves break-even ACoS measurably on low-priced items.
Why is my actual Amazon profit lower than my estimate?
Almost always because the estimate counted only referral and fulfillment fees. Storage, aged-inventory surcharges, inbound placement, returns processing, prep and the fuel surcharge are billed at the account or shipment level, so they never reach the per-unit view. Allocating them across units shipped closes most of the gap.
Where to start
Pick your top five ASINs by revenue and rebuild their unit economics from the current fee schedule, not from last year's model. Pull three months of storage, placement and returns charges, divide by units shipped, and carry that as a real per-unit line. Then compare each ASIN's break-even ACoS against what its campaigns are actually spending — the mismatches are where the money is. If you would rather have someone else run that pass across the account, a free Amazon audit covers it.
