Amazon FBA Calculator: Referral and FBA Fees for 2026

When a unit sells through Fulfillment by Amazon (FBA), Amazon takes two main fees from the sale:

• The referral fee: Amazon's commission for selling on its store. It's a share of the total price the buyer pays, usually 8% to 15% depending on the category, with a minimum of $0.30 in most categories. See the full table in Amazon referral fees by category.
• The FBA fulfillment fee: a flat fee per unit to pick, pack and ship the order. It depends on the packaged size and weight, the price, the product type and the time of year.

Since April 17, 2026, Amazon also adds a 3.5% fuel and logistics surcharge on top of the fulfillment fee. It isn't printed in the rate cards, so it's easy to miss. Media items also pay a $1.80 closing fee per unit.

This calculator adds those up. It leaves out fees that depend on your inventory rather than the sale: monthly storage, aged inventory, inbound placement, the low-inventory-level fee and returns processing.

referral fee     = total price × category rate   (or the category minimum, if higher)
dimensional wt.  = length × width × height ÷ 139   (in inches; bulky items count width and height as at least 2 in)
shipping weight  = unit weight (small standard)  or  the greater of unit and dimensional weight (most other tiers)
FBA fee          = rate card[product type, season, size tier, shipping weight, price band]
surcharge        = FBA fee × 3.5%
Amazon fees      = referral fee + closing fee + FBA fee + surcharge

1. Size tier. Sort the packaged sides from longest to shortest. Amazon's size tier rules decide the tier: small standard is up to 15 × 12 × 0.75 inches and 16 ounces; large standard is up to 18 × 14 × 8 inches and 20 pounds; then small bulky, large bulky and four extra-large weight bands.
2. Shipping weight. Small standard uses the unit weight. Other tiers use the unit weight or the dimensional weight, whichever is greater, so a light but bulky box pays for its size.
3. Price band. Each rate card has three columns: items under $10, $10 to $50, and over $50. An item at exactly $10 or $50 is in the middle column.
4. Season. Peak rates apply to units shipped from October 15, 2026 to January 14, 2027. Amazon charges the rate in effect when the unit ships.

Take a made-up kitchen gadget that sells for $24.99 in Home and Kitchen. Its package is 10 × 6 × 3 inches and weighs 1.1 lb. These are the example values already in the calculator.

1. Referral fee: 15% × $24.99 = $3.75.
2. Dimensional weight: 10 × 6 × 3 ÷ 139 = 1.29 lb. That's more than the 1.1 lb unit weight, so the shipping weight is 1.29 lb.
3. Size tier: large standard, weight band 1.25+ to 1.5 lb, price band $10 to $50. The peak FBA fee is $5.73 (non-peak: $5.42).
4. Surcharge: $5.73 × 3.5% = $0.20.
5. Amazon fees: $3.75 + $5.73 + $0.20 = $9.68, or 38.7% of the price.
6. With a $5.00 product cost, $10.31 is left per unit to pay for ads, storage, returns and profit. That's a 41.3% margin before ads, so ads break even at a ROAS of 2.42.

There's no standard share, because the FBA fee is fixed per unit while the referral fee moves with price. The same package takes a much bigger bite out of a cheap item. Here's the example gadget at four prices, at peak rates:

What matters is whether enough is left after fees and product cost to pay for ads and still make a profit. Put your product cost in the calculator, then take its margin before ads to the break-even ROAS calculator to see the ROAS your ads must reach.

• Measuring the product instead of the package. Amazon uses the packaged unit. A few extra inches of box can move an item into a higher size tier or make dimensional weight the shipping weight.
• Forgetting the peak season. From October 15 to January 14 every unit pays peak rates. On the standard rate card that's 19 to 54 cents more per standard-size unit.
• Leaving out the surcharge. The 3.5% fuel and logistics surcharge isn't in Amazon's rate card tables, but it's charged on every FBA unit.
• Getting the price threshold wrong. In categories like Beauty, Health and Personal Care, crossing $10 moves the whole price from 8% to 15%. A $10.49 item can keep less than a $9.99 one.
• Treating fees as the whole cost. Storage, returns and inbound placement come on top, and they grow with slow-moving stock.

Fees set how much each sale can afford to spend on ads. But the ad side has its own trap: the ROAS you compare against that budget has to be the sales the ads actually caused. Reported ROAS counts sales from people who would have bought anyway, and misses Amazon sales from people who saw a Meta ad and searched Amazon later.

To measure what ads cause, pause them in some regions and compare. The incremental ROAS calculator turns that test into the number to hold against your break-even. See how lift is calculated for the method.