Amazon caps your FBA capacity to manage its finite warehouse space and to steer sellers toward healthy inventory levels. Your limit is set from your IPI score, your recent sales and demand forecast, and your history of using capacity. A low IPI or a lot of slow-moving stock tightens the limit, which can leave you unable to send in more even for a product that is selling. You can request extra room through Capacity Manager for a reservation fee, but the durable fix is a healthier IPI.
Andrew Erickson is the founder of Inventory Hero. He has spent years working with Amazon FBA sellers on demand forecasting, restock planning, and the cash flow side of running a private-label brand. Inventory Hero exists because every spreadsheet-based inventory system he tried eventually broke — usually right before Q4.
Improve the inputs: raise your IPI by clearing excess and stranded inventory and keeping sell-through healthy, since a better IPI generally earns more capacity. In the near term, free up room by removing slow-moving stock, and use Amazon's Capacity Manager to request more capacity by reserving cubic feet at a reservation fee, offset by a performance rebate on the inventory you sell through from that space. A 3PL can hold overflow you cannot send in yet.
What happens if I exceed my restock limit?
You generally cannot create inbound shipments beyond your capacity, so the practical effect is you are blocked from sending more until space frees up or your limit rises. If you reserve extra capacity through Capacity Manager, an overage or reservation fee may apply. The bigger cost is usually the stockout risk on a good SKU you cannot restock, which is why managing capacity proactively matters.
Read article
An Amazon restock limit is a cap on how much inventory you can send into FBA, now administered through Amazon's capacity limit system, which measures your allowance in cubic feet rather than per-SKU unit counts. The short version: your limit is driven by your IPI, your sales and forecast, and your capacity history, and when it binds you prioritize your best SKUs, free room by clearing slow stock, and can request more through Capacity Manager. Below is why the cap happens and how to work with it.
Amazon used to run separate storage limits and restock (ASIN-level quantity) limits. It has since consolidated these into a unified capacity limit system, which sets a single monthly capacity allowance, expressed in cubic feet, for how much inventory you can hold and send in. The mechanics have evolved and Amazon continues to adjust them, so treat the specifics here as the current shape and confirm details in your own account and the capacity limits documentation.1
The practical experience is the same regardless of the label: at some point, Amazon tells you that you cannot send in more until space frees up or your allowance rises.
Prioritize your best SKUs. Send in the fast movers and high-GMROI products first; do not spend scarce capacity on slow ones.
Clear excess and stranded stock. Removing excess and stranded inventory frees room immediately and raises your IPI, which can lift the limit itself.
Use a 3PL for overflow. Hold the stock you cannot send in yet at a third-party warehouse and feed it into FBA as space opens. This keeps a bulk buy from becoming a cash-and-space problem.
The goal is to make sure the capacity you do have is working for your best products, not tied up in stock that should not be there.
Beyond fixing the inputs, Amazon provides a direct path to more room:
Capacity Manager lets you request additional capacity above your baseline allowance.
Reserving capacity works through Capacity Manager: you request extra cubic feet at a reservation fee Amazon sets, charged per cubic foot per month, offset by a performance rebate credited on how much of that reserved inventory you sell through. So it pays off when you actually sell out of the reserved space, and it is just a cost if you do not. Amazon adjusts the rate, so check the current per-cubic-foot figure in Capacity Manager before you commit.
Weigh reserving against a 3PL. Paying to reserve makes sense for a proven, fast-moving SKU heading into peak. But if the reservation cost is high relative to holding overflow elsewhere (third-party ambient storage often runs on the order of tens of dollars per pallet per month plus handling), a 3PL buffer is often the better call. Never pay to reserve capacity for the slow stock that is the reason you are capped.
Requesting more is a valid tool, but it works best alongside fixing the IPI and clearing the excess that tightened your limit to begin with.
Because the modern limit is a volume allowance, not a unit count, it helps to think in cubic feet:
Find your allowance and usage in the FBA capacity dashboard, which shows your granted capacity and how much you have consumed.
Estimate what a shipment consumes. A carton's volume (length times width times height, converted to cubic feet) times the number of cartons is roughly what it draws from your allowance. A standard 18-by-14-by-12-inch carton is about 1.75 cubic feet, so a 50-carton shipment draws roughly 87.5 cubic feet; against a 500-cubic-foot grant, that single shipment is about 18 percent of your month. Size each one in the FBA restock calculator.
The practical implication: bulky, slow-moving SKUs eat capacity fast for little return, while small, fast movers sip it. When capacity is tight, that math is another reason to prioritize the small, fast SKUs and clear the bulky slow ones.
Thinking in volume rather than units also makes the trade-off clear: the same cubic feet spent on a dense fast seller returns far more than on a bulky slow one, so capacity, like cash, should flow to your best products.
Amazon restock limits cap what you can send into FBA, set through the capacity limit system from your IPI, sales, and history. When capped, prioritize your best SKUs, clear excess and stranded stock to free room and lift your IPI, lean on a 3PL for overflow, and use Capacity Manager when paying for space is justified. Manage the inputs proactively and the cap rarely bites hard. For the step-by-step fix, see how to improve your IPI score; for the underlying score, the Amazon IPI score; and for the capacity system itself, FBA capacity limits.
Amazon's FBA capacity limit system (the unified, cubic-feet monthly allowance that replaced separate storage and restock limits) is described in Seller Central's capacity limits and Capacity Manager help pages (sellercentral.amazon.com). Amazon has revised the mechanics over time; confirm the current details there. ↩