Amazon FBA Storage Fees Calculator: Estimate Your Bill

The formula

Unlike Amazon's per-unit fulfillment fee, storage fees are billed by space occupied over time:

Monthly storage fee = daily average volume (cubic feet) × that month's rate

Where daily average volume = (total volume × days stored that month) ÷ days in the month.

To get your unit's cubic feet from its packaged dimensions in inches:

Cubic feet per unit = (length × width × height) ÷ 1728

Worked example

For a standard-size item measuring 12" × 10" × 8", storing 100 units in a non-peak month:

1. Volume per unit: 12 × 10 × 8 = 960 cubic inches ÷ 1728 = 0.556 cubic feet
2. Total volume: 100 units × 0.556 = 55.6 cubic feet
3. Monthly fee at the non-peak standard rate: 55.6 × $0.78 = about $43.34

Swap in the peak-season rate ($2.40/cu ft) for the same volume and the same inventory costs roughly $133.44 for the month instead — a direct illustration of why storage costs jump in Q4.

For the current base rates, utilization surcharge tiers, and how long-storage (180+ day) surcharges stack on top, see our FBA storage fees and aged inventory surcharge pages — this calculator page covers the base monthly formula only.

What else affects your total Amazon costs

A full profitability picture needs more than the storage line. The other inputs that typically go into a complete calculation are: sale price, product cost, referral fee (category-dependent, commonly 15%), fulfillment fee (based on size/weight tier), inbound shipping to Amazon's warehouse, and advertising spend. One dated detail worth knowing if you're budgeting for prep costs: Amazon stopped offering its own FBA prep service as of January 1, 2026.

Use Amazon's official calculator to confirm the exact number

For a precise, account-specific estimate — including your actual referral fee category and fulfillment tier — Amazon's own FBA Revenue Calculator inside Seller Central is the authoritative source. Use the formula above to sanity-check your storage line item, then confirm the full picture in the official tool.