Packed item size
Based on Amazon US size tiers effective Jan 15, 2026. Amazon’s own measurement of your item is final.
How Amazon size tiers work
Sort the sides
Amazon calls the longest side length, the next width (median) and the shortest height. An item must fit every limit of a tier.
Dimensional weight
L × W × H ÷ 139Used for large standard, bulky and extra-large items up to 150 lb. For bulky and extra-large, width and height count as at least 2 in.
Shipping weight
The greater of unit weight and dimensional weight. Small standard items and extra-large items over 150 lb use unit weight only.
Length + girth
longest + 2 × (median + shortest)Bulky items must stay at or under 130 in. Above that, the item is extra-large.
Frequently asked questions
What is the small bulky size tier?
A tier Amazon added on Jan 15, 2026, between large standard and large bulky: up to 37 × 28 × 20 in, 130 in length + girth and 50 lb.
Is size tier based on unit weight or shipping weight?
The tier is set by dimensions and unit weight. Fees are then charged on shipping weight, which may be the dimensional weight.
How do I move to a cheaper size tier?
Trim the package. Getting under 18 × 14 × 8 in or the 0.75 in small standard thickness often cuts fees the most.
Does this work for Amazon UK or EU?
No. Those marketplaces use different tiers and metric limits. This tool covers Amazon US only.
Related free tools
Sources: Seller Labs: Amazon FBA size tiers 2026 · Acadia: Amazon US fee changes in 2026 · AMZ Prep: Amazon FBA fees 2026 · Amazon Seller Central: Product size tiers