How the size tier checker works
Amazon classifies every unit by its longest, median, and shortest side plus its billing weight — the greater of actual weight and dimensional weight (L×W×H ÷ 139). Small Standard, Large Standard, Small Bulky, and Large Bulky each have hard limits; crossing any one of them moves you up a tier and raises the fulfilment fee on every unit. The result shows which limit you are over and by how much.
Frequently asked questions
What are the 2026 Amazon FBA size tiers?
Small Standard (≤16 oz, ≤15×12×0.75 in), Large Standard (≤20 lb, ≤18×14×8 in), Small Bulky (≤50 lb, ≤59×33×33 in, length + girth ≤130 in), then Large Bulky and Extra-Large tiers above that.
What is dimensional weight?
Length × width × height in inches divided by 139, in pounds. If it exceeds actual weight, Amazon bills on the dimensional figure — which is why oversized packaging costs money even when the product is light.
Does the checker use product or packaging size?
Packaging. Amazon measures the shipped unit including its box, so measure what you actually send to the fulfilment centre.