The New Dimensional Weight Calculation and FBA Fulfillment Fee Rates, Effective 2/22/18
Each year Amazon makes FBA fee changes relative to the changing market costs it experiences in providing fulfillment, transportation and customer services. This year, the FBA fee changes will apply to shipments leaving FBA fulfillment centers on or after February 22nd.
Among the 2018 FBA Fee changes changes to note:
- Fulfillment fees for most product size tiers and weights will be adjusted
- Fees will apply throughout the entire year; Amazon will no longer have a separate rate for the months of October through December
- Amazon is adjusting the way they calculate dimensional weight in order to better align with industry standards
- FBA inventory fees will change in 2018, probably sometime in the first (changes TBD as of this writing)

* Intended to be used and must be used for informational purposes only. Fees may be changed by Amazon at any time.
The New FBA Fee Changes
With this year’s FBA Fee changes, Amazon is lowering the divisor they apply to the unit volume (based on length x width x height in inches) from 166 to 139. If you use Multi-Channel Fulfillment and/or the Inventory Placement Service, keep in mind that dimensional weight is also used to calculate those fees as well and should be included in your accounting when adjusting for FBA fee changes.
As well, the below chart reflects the following changes and provides a comparative snapshot of the FBA fee changes, effective February 22nd of 2018, relative to those in effect prior:
- Rate increases for Large Standard-Size items weighing more than 1 lb. and all Small Oversize and Medium Oversize items
- Decreases in fees for Large Oversize and Special Oversize rates
- No change to Small Standard Size rate

In the above table, sizes in the far left column are defined as follows:
- Small standard-size: packaged items weighing 12 oz. or less with longest side equal to 15 inches or less, shortest side equal to 0.75 inches or less, median side = 12 inches or less
- Large standard-size: packaged items weighing 20 lb. or less with its longest side equal to 18 inches or less, its shortest side equal to 8 inches or less, and its median side equal to 14 inches or less
- Small oversize: any packaged unit weighing 70 lb. or less with its longest side equal to 60 inches or less, its median side equal to 30 inches or less, and its longest side plus girth equal to 130 inches or less
- Medium oversize: any packaged unit weighing 150 lb. or less with its longest side equal to 108 inches or less, and its longest side plus girth equal to 130 inches or less
- Large oversize: any packaged unit weighing 150 lb. or less with its longest side equal to 108 inches or less, and its longest side plus girth equal to 165 inches or less
- Special oversize: any packaged unit with weight exceeding one or more of the following: over 150 lb. (dimensional weight or unit weight), exceeding 108 inches on its longest side, or over 165 inches when longest side is added to girth. In addition, products that Amazon determines require special handling or delivery will qualify for Special Oversize
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Other definitions:
- Median side: the dimension of a product that is neither the longest nore the shortest side
- Girth: equivalent to 2 x (median side + shortest side)
- Unit weight: the weight of an individual unit
To determine which product size tier your product fits under, refer to Amazon's posted product size tier.
For questions on the FBA fee changes, call Awesome Dynamic at (800) 238-1811. Our fulfillment experts stand ready to assist.