Amazon Volumetric Weight for Sellers
Amazon works out shipping fees on the higher of the dead weight and the volumetric weight of your packed product, and the volumetric weight uses the packed L × B × H in cm ÷ 5000. Measure the product in its final box or polybag, not the bare item.
Enter the packed size and weight above to see which weight slab applies. A bulky but light item, like a cushion or a toy, often lands in a heavier slab than its real weight; a tighter pack can bring it down. Check the exact rules on your Seller Central fee page.