How does the calculator work out my FBA size tier?

It sorts your three dimensions longest to shortest and checks them against each tier in turn. Small standard needs 15 x 12 x 0.75 in and 16 oz or less. Large standard allows 18 x 14 x 8 in and 20 lb. Large bulky allows 59 x 33 x 33 in and 50 lb. Anything past that is extra-large. Measure the unit as it ships, box included, because Amazon measures the packed unit and not the product.

What is the 3.5% fuel and logistics surcharge?

It is a percentage added on top of the FBA fulfilment fee, in force from 17 April 2026. It does not touch the referral fee or storage. The toggle is on by default and appears as its own line in the ledger, so you can see exactly what it adds. Switch it off to compare against the fee card as it stood before that date.

Why does the referral fee differ by category?

Amazon sets a different percentage per category, and several categories change rate at a price threshold. Beauty, Health and Personal Care charges 8% at $10 or less and 15% above it, on the whole price. Jewellery charges 20% up to $250 and 5% only on the portion above. Amazon Device Accessories is 45%. Every category carries a $0.30 per unit minimum, which is what makes very cheap units unworkable.

How does the calculator handle returns?

It averages the cost of returns across every unit sold. For the returned share, the sale price is reversed and the referral fee comes back less Amazon's refund administration fee, which is 20% of the referral fee capped at $5. The fulfilment fee is not refunded, and the unit is treated as unsellable, so the cost of goods is lost. A 3% return rate on a $34.99 unit costs roughly $0.92 per unit sold.

What is billable weight and when does dimensional weight apply?

Billable weight is what Amazon charges the fulfilment fee on. For small and large standard units at or under 1 lb, that is simply the unit weight. Above 1 lb on standard tiers, and always on large bulky and extra-large, it is the greater of the unit weight and the dimensional weight, which is length times width times height divided by 139. Light but bulky products get billed on volume.

Which Amazon fees are not modelled here?

Peak fulfilment fees from 15 October to 14 January, low-inventory-level fees, aged inventory surcharges, long-term storage, removals and disposals, and the Ships in Product Packaging discount. Apparel and dangerous goods run on separate rate cards. Storage seasonality is covered by the season toggle, but the fulfilment rates used are always non-peak.

How is break-even ACoS derived from this?

Break-even ACoS is your profit before advertising divided by the sale price. The calculator takes net profit, adds the PPC line back, and divides by price. On the worked example that is $16.22 of profit before ads on a $34.99 price, or 46.4%. Spend above that on ads and the unit loses money. For campaign-level ACoS and TACoS work, use the ACoS and TACoS calculator.

Free tool

Amazon FBA profit calculator

Enter a price, a landed cost and the packed dimensions to see the referral fee, the FBA fulfilment fee, storage, ads and returns come off one unit. It works out the size tier and billable weight for you. All figures in USD.

Fee card: Amazon's 2026 US FBA rate card via GoatConsulting and AMZ Prep, effective 15 January 2026. Amazon's own Revenue Calculator is the final word on any single ASIN.

Price and cost

Sale price per unit (USD)

What the buyer pays, before promotions

Landed cost per unit (USD)

Manufacture, freight and duty, delivered to the warehouse

Packed size and weight

Measure and weigh the unit as it ships, box included. These decide the size tier, the billable weight and the storage bill.

Dimensions (inches)

Length

Width

Height

Unit weight

Unit

Size tier

Override this if Seller Central has classified your unit differently, which happens with soft packaging.

Storage and season

Months of storage per unit

Roughly how long a unit sits in the network before it sells

Storage season

October to December storage costs roughly three times as much per cubic foot.

Ads, returns and extras (optional)

Leave these blank to see the fee-only picture. Most sellers are caught out by the last two.

How do you want to enter ad cost?

Per unit ($)TACoS (%)

PPC cost per unit sold (USD)

Ad spend for the period divided by all units sold, organic included

Returns rate

Share of units returned. We assume the unit comes back unsellable.

Inbound placement and prep per unit (USD)

Placement service fee, prep, labelling, polybags

Other per-unit cost (USD)

Inserts, samples, a share of software, anything else

Apply the 3.5% fuel and logistics surcharge (from 17 April 2026)

Turn it off to see fees as they stood before that date.

Fill in the sale price, landed cost, the three dimensions and the unit weight to see the fee ledger.

How the numbers are calculated

Fee card: Amazon's 2026 US FBA rate card via GoatConsulting and AMZ Prep, effective 15 January 2026. Non-peak rates, non-apparel, no SIPP discount. The fuel and logistics surcharge of 3.5% applies from 17 April 2026.

dimensional weight (lb) = L x W x H / 139
billable weight = unit weight for standard tiers at or under 1 lb, otherwise max(unit weight, dimensional weight)
cubic feet = L x W x H / 1728
storage = cubic feet x rate per cu ft x months held
FBA fee = rate card cell for the tier, weight band and price band
surcharge = FBA fee x 3.5% when the toggle is on
referral fee = category rate on price, minimum $0.30
refund admin fee = min(20% of referral fee, $5.00)
returns cost = returns rate x (price - referral fee + refund admin fee)
net profit = price - landed cost - referral - FBA - surcharge - storage - PPC - returns - inbound - other
net margin = net profit / price
ROI = net profit / landed cost
break-even ACoS = (net profit + PPC) / price
break-even price = the price at which net profit is 0

Returns are averaged across every unit sold rather than modelled as a separate batch. A returned unit has its sale price reversed, gets the referral fee back less the refund administration fee, keeps the fulfilment fee, and is written off, so the cost of goods is lost. Break-even price is solved by bisection, because the referral fee, the fulfilment price band and the returns cost all move when the price moves.

Caveats worth reading

Peak fulfilment fees apply from 15 October to 14 January and are higher than the rates used here. This page models non-peak fulfilment. The storage season toggle is separate and does cover the October to December storage rise.
Low-inventory-level fees, aged inventory surcharges, long-term storage fees, removals and disposals are not modelled at all.
The Ships in Product Packaging (SIPP) discount is not applied. If your unit qualifies, your real fulfilment fee is lower.
Apparel and dangerous goods run on different rate cards. So do Small and Light style programmes where they still exist.
Inbound placement service fees vary by how you split a shipment. Enter your own figure rather than trusting a default.
Amazon's Revenue Calculator is authoritative. Use this page to screen products quickly, then confirm the winner there before you place an order.

More on how we work and what we verify: how we test.

Why does a cheap product often lose money on Amazon?

Because the fulfilment fee barely moves. A small standard unit at 6 oz costs about the same to ship whether it sells for $12 or $40, and the referral fee minimum of $0.30 does not scale down either. On a $12 unit that fixed cost eats a third of the price before you have paid for the goods.

That is the real argument for bundles and higher price points. Two bottles in one box pay one fulfilment fee, one referral fee on the bundle price, and one slice of ad spend. Run both through the ledger above and the difference is usually larger than sellers expect.

What does an Amazon FBA profit calculator actually work out?

It takes one unit and subtracts every cost Amazon applies to it: the referral fee set by your category, the fulfilment fee set by your size tier and billable weight, monthly storage on the volume the unit occupies, then your own ad spend, returns and prep. What is left is net profit per unit, and dividing that by the price gives net margin.

The reason to do this before ordering rather than after is that three of those numbers are decided by the box, not by you. Add half an inch to the shortest side and a small standard unit becomes large standard, which on a 6 oz product is about a dollar a unit. On a thousand units that is the difference between a good order and a mediocre one.

Why do size tier and billable weight matter more than price?

Because the fulfilment fee is a fixed cost per unit and the referral fee is not. Raise the price and the referral fee rises with it, so the percentage stays the same. The fulfilment fee stays flat, which means it hurts most at low price points and barely registers at high ones. That is why the same product can be unviable at $12 and comfortable at $32.

Billable weight is the other lever. Standard units at or under 1 lb are charged on their actual weight, so a light product in a tight box gets the cheapest cells on the card. Go over a pound, or go bulky, and Amazon starts comparing your weight against length times width times height divided by 139 and charging the higher of the two. Packaging design becomes a margin decision at that point.

How should you read the break-even numbers?

Break-even ACoS is the ceiling on ad spend per sale. It is profit before advertising divided by price, so it tells you the ACoS at which advertising exactly consumes your remaining margin. Break-even sale price is the other side of the same question: the lowest price that still leaves nothing behind, useful when you are deciding how far a promotion can go.

Neither is a target. Both are limits. Once you know the ceiling, take it over to the ACoS and TACoS calculator to judge whether your current campaigns sit under it, and to the search term miner to find the spend that is pushing you over.

Which tools help you find products that clear this margin?

Helium 10 has a Profitability Calculator plus Black Box, which lets you filter candidate products by price, weight and review count before you pay for samples. Screening on weight first is the fastest way to avoid products whose fee band eats the margin. SmartScout is more useful for the second question: whether the category will actually pay the price your margin needs. For the wider picture, see our guide to the best AI tools for Amazon FBA sellers, and our testing methodology. Amazon's own Revenue Calculator remains the authoritative check on any single ASIN.

Frequently asked questions

How does the calculator work out my FBA size tier?: It sorts your three dimensions longest to shortest and checks them against each tier in turn. Small standard needs 15 x 12 x 0.75 in and 16 oz or less. Large standard allows 18 x 14 x 8 in and 20 lb. Large bulky allows 59 x 33 x 33 in and 50 lb. Anything past that is extra-large. Measure the unit as it ships, box included, because Amazon measures the packed unit and not the product.
What is the 3.5% fuel and logistics surcharge?: It is a percentage added on top of the FBA fulfilment fee, in force from 17 April 2026. It does not touch the referral fee or storage. The toggle is on by default and appears as its own line in the ledger, so you can see exactly what it adds. Switch it off to compare against the fee card as it stood before that date.
Why does the referral fee differ by category?: Amazon sets a different percentage per category, and several categories change rate at a price threshold. Beauty, Health and Personal Care charges 8% at $10 or less and 15% above it, on the whole price. Jewellery charges 20% up to $250 and 5% only on the portion above. Amazon Device Accessories is 45%. Every category carries a $0.30 per unit minimum, which is what makes very cheap units unworkable.
How does the calculator handle returns?: It averages the cost of returns across every unit sold. For the returned share, the sale price is reversed and the referral fee comes back less Amazon's refund administration fee, which is 20% of the referral fee capped at $5. The fulfilment fee is not refunded, and the unit is treated as unsellable, so the cost of goods is lost. A 3% return rate on a $34.99 unit costs roughly $0.92 per unit sold.
What is billable weight and when does dimensional weight apply?: Billable weight is what Amazon charges the fulfilment fee on. For small and large standard units at or under 1 lb, that is simply the unit weight. Above 1 lb on standard tiers, and always on large bulky and extra-large, it is the greater of the unit weight and the dimensional weight, which is length times width times height divided by 139. Light but bulky products get billed on volume.
Which Amazon fees are not modelled here?: Peak fulfilment fees from 15 October to 14 January, low-inventory-level fees, aged inventory surcharges, long-term storage, removals and disposals, and the Ships in Product Packaging discount. Apparel and dangerous goods run on separate rate cards. Storage seasonality is covered by the season toggle, but the fulfilment rates used are always non-peak.
How is break-even ACoS derived from this?: Break-even ACoS is your profit before advertising divided by the sale price. The calculator takes net profit, adds the PPC line back, and divides by price. On the worked example that is $16.22 of profit before ads on a $34.99 price, or 46.4%. Spend above that on ads and the unit loses money. For campaign-level ACoS and TACoS work, use the ACoS and TACoS calculator.