What Is Carrying Cost for Amazon FBA?
Carrying cost is every dollar you spend simply to hold inventory, whether or not that inventory sells. In a traditional warehouse, textbooks peg carrying cost at 20-25% of inventory value per year. FBA sellers face a much steeper number because Amazon's fee structure stacks monthly storage fees, seasonal surcharges, and aged inventory penalties on top of the usual capital and shrinkage costs.
The components of FBA carrying cost break into five buckets: Amazon storage fees (monthly per-cubic-foot charges), aged inventory surcharges (starting at 181 days), long-term storage fees, cost of capital (the return you forgo by having cash locked in product), and shrinkage or damage (units lost or damaged in Amazon's network). When you add these up with real numbers, carrying cost for a typical FBA seller lands between 35% and 50% of inventory value annually.
Understanding your true carrying cost matters because it feeds directly into reorder quantity decisions, minimum margin thresholds, and whether a slow-moving SKU is worth keeping in your catalog. Underestimate it and your profit calculations are fiction.
Carrying Cost Formula for FBA
The annual carrying cost per unit combines every holding expense:
Annual Carrying Cost = Storage Fees + Capital Cost + Aged Surcharges + Shrinkage + InsuranceHere is what each component looks like for a standard-size FBA product:
| Component | Typical Annual Cost Per Unit | Notes |
|---|---|---|
| Monthly storage fees | $0.50 - $2.00 | $0.87/cu ft (Jan-Sep), $2.40/cu ft (Oct-Dec) |
| Aged inventory surcharge | $0 - $6.90+ | Kicks in at 181 days; escalates at 271, 365+ days |
| Cost of capital | 8-15% of unit cost | Credit card rate, loan interest, or opportunity cost |
| Shrinkage and damage | 1-3% of unit cost | Units lost, damaged, or unsellable at Amazon |
| Insurance | 0.5-1% of unit cost | Product liability and inventory insurance |
To express carrying cost as a percentage:
Carrying Cost % = (Total Annual Carrying Cost Per Unit / Landed Cost Per Unit) × 100Worked Example: Real FBA Carrying Cost
Product: standard-size item, 0.25 cubic feet per unit, $8.00 landed cost, 500 units in FBA.
Monthly storage fees (annual): 0.25 cu ft × $0.87 × 9 months = $1.96, plus 0.25 cu ft × $2.40 × 3 months (Q4) = $1.80. Total: $3.76 per unit per year.
Cost of capital: $8.00 × 10% = $0.80 per unit per year.
Shrinkage: $8.00 × 2% = $0.16 per unit per year.
Insurance: $8.00 × 0.5% = $0.04 per unit per year.
Total annual carrying cost per unit: $3.76 + $0.80 + $0.16 + $0.04 = $4.76
Carrying cost as % of inventory value: $4.76 / $8.00 = 59.5%
For 500 units, that is $2,380 per year just to hold the inventory. Storage fees alone ($3.76) dwarf the capital cost ($0.80). This is what makes FBA carrying cost so much higher than the textbook number.
Why FBA Carrying Cost Is Different
Three Amazon-specific factors push FBA carrying cost well above traditional warehouse rates.
Seasonal storage fee spikes. The Q4 rate ($2.40/cu ft) is 2.8x the standard rate. Sellers who stock up for holiday demand pay a premium for every unit sitting in FBA during October through December. If inventory doesn't sell through quickly in Q4, the storage fees can erase a significant chunk of holiday margin.
Aged inventory surcharge tiers. Amazon penalizes slow-moving stock starting at 181 days. The surcharge escalates at 271 days and again at 365+ days. These penalties can exceed the original product cost for very slow inventory. Monitoring your Inventory Performance Index (IPI) score helps you stay ahead of these thresholds.
Storage limit pressure. When your IPI drops below Amazon's threshold, storage capacity gets restricted. This forces sellers into a cycle of rushing inventory in and out, increasing ordering frequency and total logistics costs.
Common Carrying Cost Mistakes
Using the textbook 20-25% rate. Plugging a generic carrying cost percentage into your EOQ or reorder models understates the real cost of holding FBA inventory. Your reorder quantities will be too large and you will overstock. Use your actual Amazon storage fees, capital cost, and surcharge exposure to calculate a number specific to your catalog.
Ignoring the Q4 storage fee spike. Sellers who plan inventory levels using the $0.87/cu ft rate year-round underestimate Q4 holding costs by nearly 3x. Excess inventory going into October means storage fees can wipe out margin on slow-moving units during the most profitable quarter.
Forgetting opportunity cost of capital. Cash tied up in 90 days of safety stock is cash not available for new product launches, PPC campaigns, or supplier negotiations. Even if you are not paying loan interest, your capital has an opportunity cost. Most FBA operators should use 10-15% as their annual capital cost rate.
Related Glossary Terms
Revenue minus all variable costs per unit, including Amazon fees.
Read →The bottom-line profit on each unit after every cost is subtracted.
Read →The complete set of fees Amazon charges per unit sold.
Read →Penalty fees on inventory stored longer than 365 days.
Read →Monthly surcharge on units stored 181+ days in FBA.
Read →Frequently Asked Questions
What is a good carrying cost percentage for FBA?
Most FBA sellers see annual carrying costs of 35-50% of inventory value at cost. If your number is below 30%, you are probably missing components like capital cost or seasonal storage spikes. Above 50% usually signals excess aged inventory or heavy Q4 storage exposure.
How do Q4 storage fees affect carrying cost?
Amazon charges $2.40 per cubic foot from October through December, nearly triple the $0.87 standard rate. A product sitting in FBA during Q4 accumulates storage fees roughly 2.8x faster, which can push quarterly carrying cost above 15% of inventory value for that period alone.
Does carrying cost include Amazon's referral fee?
No. Referral fees and FBA fulfillment fees are selling costs, charged only when a unit sells. Carrying cost covers expenses incurred simply by holding inventory, whether or not it sells: storage fees, capital cost, surcharges, and shrinkage.
How do I reduce my FBA carrying cost?
Improve inventory turnover so units spend fewer days in FBA warehouses. Remove or liquidate inventory approaching the 181-day aged surcharge threshold. Use Amazon Warehousing and Distribution (AWD) for overflow stock at lower rates. Right-size reorder quantities so you carry 30-60 days of supply rather than 90+.