What Is Reserve Quantity in Amazon FBA?
Reserve quantity is the number of FBA units that Amazon has set aside and temporarily made unavailable for sale. These are units you own and that physically sit in Amazon's fulfillment centers, but customers cannot purchase them right now. Your reserve quantity shows up in the Manage FBA Inventory page as the difference between your total inventory and your available inventory.
Understanding reserve quantity is essential for accurate reorder timing and inventory planning. If you have 500 total units but 200 are in reserve, you only have 300 available units generating sales. Sellers who base reorder decisions on total inventory rather than available inventory consistently reorder too late and risk stockouts.
Reserve quantity breaks down into three categories, each with different causes and expected durations. Knowing which type of reserve is tying up your units tells you whether the situation is normal (customer orders), temporary (FC transfer), or potentially problematic (FC processing).
Three Types of Reserve Quantity
| Reserve Type | What It Means | Typical Duration |
|---|---|---|
| Customer Orders | Units purchased by customers, awaiting shipment from the FC | 1-3 days |
| FC Transfer | Units being moved between fulfillment centers to position closer to demand | 1-14 days (up to 30 in rare cases) |
| FC Processing | Units under investigation, being measured/weighed, or in removal processing | Variable, days to weeks |
Customer Orders are the healthiest type of reserve. These are sold units waiting to ship. They cycle through quickly (usually within 24-48 hours) and indicate strong sales velocity. High customer order reserves on a product are a good sign.
FC Transfer reserves occur when Amazon's demand algorithm predicts customer orders in other regions and moves your inventory closer to those customers. This is Amazon optimizing delivery speed, but it temporarily reduces your available quantity. During peak season, FC transfers can be especially aggressive, tying up 10-20% of your inventory for days.
FC Processing reserves are the ones to watch. These units are sidelined for dimension/weight verification, damage investigation, or pending removal orders. If FC Processing reserves stay elevated for more than a week, open a support case to investigate.
Worked Example
You sell a yoga mat (ASP: $34.99) with strong daily velocity of 15 units/day. Here's your current inventory snapshot:
| Category | Units | % of Total |
|---|---|---|
| Available | 320 | 64% |
| Reserved: Customer Orders | 45 | 9% |
| Reserved: FC Transfer | 120 | 24% |
| Reserved: FC Processing | 15 | 3% |
| Total | 500 | 100% |
At 15 units/day, your 320 available units will last 21 days. But if you looked at total inventory (500 units), you'd calculate 33 days of coverage and think you have plenty of time.
Your reorder point for this product is set at 25 days of coverage (based on a 65-day lead time with 10 days of safety stock). Using available inventory, you should have reordered 4 days ago. Using total inventory, you wouldn't reorder for another 8 days. That's a 12-day gap that could result in a stockout if the FC Transfer units don't become available quickly.
The 120 units in FC Transfer (24% of total) is higher than typical. This often happens when Amazon is redistributing inventory ahead of a promotional event or seasonal demand shift. Those units will eventually become available, but you can't count on when.
FBA-Specific Context
Amazon charges monthly storage fees on ALL units in their fulfillment centers, including reserved inventory. Your reserve quantity still ages for purposes of the aged inventory surcharge. Units stuck in FC Processing for weeks are aging without generating sales, which is a double penalty.
You can monitor your reserve quantity in Seller Central under Manage FBA Inventory. Click the reserved quantity number for any ASIN to see the breakdown by type. The Reserved Inventory report (under Reports > Fulfillment) gives you a downloadable view across your entire catalog.
Reserve quantity also affects your sell-through rate calculations. Amazon calculates sell-through based on units shipped vs. average on-hand inventory (which includes reserved units). High reserve quantities inflate your average on-hand denominator, making your sell-through rate look worse than your actual selling pace.
This is distinct from "stranded inventory," which refers to units in FBA that have no active listing associated with them. Stranded units don't show up in reserve quantity; they show up in the Fix Stranded Inventory dashboard.
Common Mistakes
1. Reordering based on total units instead of available units. This is the most dangerous reserve quantity mistake. Your reorder calculations should use available inventory, not total inventory. Reserve units, especially FC Transfers, are not sellable and may not become available before you stockout. Always subtract reserve quantity from total to get your true sellable coverage.
2. Ignoring persistent FC Processing reserves. A small FC Processing reserve (under 5% of total) is normal. But if FC Processing reserves stay elevated for 7+ days or represent more than 10% of your total inventory, something is wrong. This could indicate Amazon is investigating your product dimensions, a batch has quality issues, or a removal order is stuck. Open a support case promptly.
3. Confusing reserve quantity with inventory turnover problems. High reserve quantity doesn't mean slow-moving inventory. If 30% of your units are in FC Transfer, your inventory is actively being positioned for faster delivery, which is bullish. The issue only becomes a problem when reserves prevent timely reorders or when FC Processing units sit unresolved. Understand which type of reserve you're dealing with before reacting.
Reserve Quantity FAQ
Why is my reserved quantity so high?
High reserved quantity usually means Amazon is actively transferring your inventory between fulfillment centers (FC Transfer) to position it closer to customers. This is normal during high-demand periods. If FC Processing reserves are high, Amazon may be inspecting or measuring your units.
Does reserved inventory count toward storage fees?
Yes. Amazon charges monthly storage fees on all units in their fulfillment centers, including reserved inventory. Reserved units also count toward aged inventory surcharges if they sit long enough.
How do I check my reserved inventory in Seller Central?
Go to Inventory > Manage FBA Inventory in Seller Central. The Reserved column shows total reserved units. Click the number to see the breakdown by type: Customer Orders, FC Transfer, and FC Processing.
Should I account for reserve quantity when reordering?
Yes. Base your reorder decisions on Available inventory, not Total inventory. Reserved units are not sellable, so if you use total quantity for reorder calculations, you will reorder too late and risk a stockout.
What's the difference between reserve quantity and stranded inventory?
Reserve quantity refers to FBA units temporarily unavailable for sale (customer orders, FC transfer, FC processing) but still actively in your catalog. Stranded inventory refers to units in FBA with no active listing attached, often due to listing suppressions or ASIN issues. They show up in different reports and require different fixes.