1. Check the weight band
Fees step up at fixed weights (every 2 oz for small standard, every 4 oz for large standard up to 3 lb). A unit half an ounce over a line pays the higher row on every sale. Lighter inserts, a thinner box or a poly mailer can drop it back.
2. Get out of dimensional weight
For large standard and above, Amazon bills on box volume ÷ 139 if that is heavier than the unit. A box that is 10% smaller on each side has 27% less volume.
3. Fit a smaller tier
0.75 in is the small standard thickness limit; 18 in and 8 in bound large standard; 37 in bounds small bulky. A slightly flatter or shorter pack can move a whole tier.
4. Use the price bands
Items under $10 get Low-Price FBA rates; items over $50 pay more. Near $10 and $50, a lower price can earn more. See the numbers.
5. Choose inbound splits deliberately
Sending to a single location (minimal split) costs a placement fee per unit; Amazon-optimized splits are free. Compare the options in Send to Amazon every time.
6. Keep stock above 28 days
Below 28 days of supply on both the 30- and 90-day measures, every unit pays the low-inventory-level fee.
7. Clear old stock before 271 days
The aged-inventory surcharge jumps at 271 days. Use the storage calculator to compare keeping with removal.
8. Plan Q4
Storage costs about three times as much from October to December, and peak fulfillment fees run October 15 to January 14. Send holiday stock to arrive in time, not months early.
9. Get SIPP certified for bulky items
Non-certified bulky items pay a packaging fee of about $2.07 per unit on average.
Putting several together
Example: a 12.5 oz item in a 9 × 6 × 2 inch box at $10.49 pays $4.76 to fulfill. Repacked to 8 × 6 × 1.5 in at 11.5 oz and priced at $9.99, it pays $3.50, and nets $0.86 more per unit despite the lower price. For the original version the calculator's fee-cliff check finds: “Pricing at $9.99 moves you to Low-Price FBA rates and earns more per unit than $10.49.”
Run your catalog through the bulk calculator to find every product with a nearby cliff.