From paper clips to bedroom sets, sellers ship products of all shapes and sizes to Amazon each day. To understand how FBA sets fees based on package dimensions—and how you can lower the fees you pay—let’s look at the process.

Follow the product

The seller packages their product and ships it to Amazon.
Once the package arrives, Amazon carefully weighs and measures it. Precision counts, so we use high-tech scanners and measurement tools as often as possible. We determine length (the longest side of the package), width (the median side), height (the shortest side), and weight.
Uh-oh! Some packing tape is hanging out of the box. The scanner counts that as part of the package’s total area
Package dimensions help determine fulfillment fees. To reduce variation and avoid unnecessary fees, always pack soft items tightly.
When many sellers offer the same product, random samples are measured. The fulfillment fee for that product’s size tier is based on the packaging attributes of these samples.
Avoid higher fees by making sure no packing material, tape, or other items are sticking out of your package.
Now that we know the package’s size and weight, it’s time to determine its FBA fulfillment fee. To do so, we follow three steps:
1. Identify size tier
2. Determine billing weight
3. Calculate fee

1. Identifying size tier

We first determine which size tier your package falls into. The table shows the maximum weights and dimensions for each tier.
FBA size tier
Longest side
Median side
Shortest side
Length + girth*
Packaging weight
Small standard

Large standard
12 oz

20 lb




4 oz

Small oversize

Medium oversize

Large oversize

Special oversize
70 lb

150 lb

150 lb

over 150 lb



over 108"









over 165"
16 oz

16 oz

16 oz

16 oz
*Girth is a unit measure, equivalent to 2 x (median side + shortest side)

The size tier is important because it determines the packaging weight and your fees. As shown in the table:
  • Standard-size packages have 4 oz of packaging weight.
  • Oversize packages have 16 oz of packaging weight.
Tip: If you manufacture boxes to fit into a size tier, be sure to leave a small tolerance for any measurement variation.

2. Determine billing weight

Now that we know the packaging weight, we add it to either the package’s specific unit weight or its dimensional weight, whichever is greater. This gives us the billing weight.
  • We use unit weight (the item’s actual weight) for all standard-size packages that weigh less than 1 lb, as well as for all special oversize packages.

  • We use dimensional weight if it is greater than the unit weight for all other size tiers. Dimensional weight is calculated in inches as length times width times height, divided by 139
Tip: For light and bulky items, the dimension weight is generally greater than the unit weight.

3. Calculating fee

Finally, we add the packaging weight from step 1 to the billing weight from step 2 and round up to the nearest pound. The rate is a function of the size tier and weight. For more information, go to FBA fulfillment fees for orders on Seller Central.
Reminder: Anything that sticks out of your package could move you into a higher size tier, so pack with care!
Note: Fulfillment and storage fees vary between peak and off-peak periods.
Amazon puts millions of products through this process every single day! What’s most important to remember is that smart packaging leads to lower fees.

Pack tightly. Pack carefully. Pack consistently.