Overview

Amazon will revise its Fulfilled‑by‑Amazon (FBA) fee structure beginning in 2026. The new model evaluates each shipment by the higher of actual weight or dimensional weight across all major size categories. Sellers with products that are light but occupy large boxes—such as pillows, yoga mats, storage bins, and seasonal décor—should expect noticeably higher per‑unit fees and may need to adjust pricing or packaging strategies.

Key Points

• Dimensional weight now universal — Large standard, small bulky, large bulky and extra‑large tiers all charge based on the greater of physical or calculated volume weight.
• Standard divisor of 139 — Amazon computes dimensional weight by multiplying length, width and height (in inches) and dividing the result by 139, then rounding up to the next whole pound.
• Low‑density items hit hardest — Products that weigh under a pound but require a box larger than 12 × 8 × 6 inches can see fees jump by 5‑10 times the previous amount.
• Multiple tier jumps possible — When dimensional weight pushes a SKU into a higher fee bracket, the cost increase can span several tiers, not just a single step.
• SIPP certification offers relief — Items enrolled in the Ships In Product Packaging (SIPP) program qualify for reduced fulfillment fees and avoid packaging surcharges that range from $0.51 to $1.04 per unit.
• Small‑standard and extra‑large exceptions — Items under 12 oz and those exceeding 150 lb remain charged on actual weight only, preserving the old calculation for those extremes.

How the Dimensional‑Weight Formula Works

1. Measure the package — Record length, width and height in inches. Example: a box measuring 12 × 8 × 6 inches.
2. Calculate cubic volume — Multiply the three dimensions (12 × 8 × 6 = 576 cubic inches).
3. Apply the divisor — Divide the volume by 139 (576 ÷ 139 ≈ 4.14).
4. Round up — Round the result to the next whole pound, yielding a dimensional weight of 5 lb.