Amazon FBA Restock Limits: How to Manage Inventory Caps and Keep Selling

Amazon FBA restock limits are caps on the maximum amount of inventory a seller can send into Amazon's fulfillment network for a given product or across all products. They exist because Amazon's warehouse space is finite, and during periods of high demand (Q4, Prime Day) or tight logistics capacity, Amazon restricts how much individual sellers can send in order to manage their network efficiently.

The limits are set at the ASIN level and the storage type level. Each product has its own restock limit, and sellers also have aggregate limits by storage type: standard-size, oversize, apparel, and footwear. You can check your current limits in Seller Central under Inventory > FBA Inventory > Restock Inventory > Manage FBA Shipments.

The key metric underlying restock limits is the Inventory Performance Index (IPI). Amazon uses IPI to evaluate how efficiently you use your FBA storage space. A high IPI score means Amazon trusts you with more inventory; a low score triggers tighter limits.

For Taiwan brands shipping internationally, restock limit constraints are particularly painful: a 30–45 day ocean freight lead time means that if Amazon suddenly reduces your restock limit, you cannot quickly replenish with air freight without significant cost. Understanding and managing IPI proactively is essential.

The IPI score ranges from 0 to 1,000. Amazon sets the threshold for unlimited storage at 400. Sellers above 400 IPI are generally not restricted. Sellers below 400 face progressively tighter limits.

IPI is calculated based on four weighted factors: Excess Inventory Percentage (how much of your inventory has more than 90 days of supply — high excess inventory hurts your IPI significantly), Sell-Through Rate (your units sold and shipped in the last 90 days divided by your average units in FBA over the same period — higher is better), In-Stock Rate (what percentage of your sellable ASINs have inventory — low in-stock rate hurts IPI), and Stranded Inventory Percentage (inventory in fulfillment centers that has no active listing — even a small amount of stranded inventory impacts IPI sharply).

Most IPI problems originate from excess inventory. Sending 6 months of inventory to FBA to avoid stockouts feels safe, but Amazon penalizes you for it. The sweet spot is maintaining 30–60 days of supply — enough to avoid stockouts without triggering excess inventory flags.

IPI scores are recalculated weekly and reflected in your Seller Central dashboard. Monitor it weekly, not monthly. A score dropping below 450 is your early warning sign to take corrective action before hitting the 400 threshold.

Strategy 1 — Create removal orders for excess inventory. If you have inventory with over 90 days of supply, create a removal order to pull it back to your warehouse or a 3PL. The cost to remove is $0.97–$3.12 per unit depending on size. This is usually far cheaper than the storage fees and IPI penalties from letting it sit.

Strategy 2 — Run a promotion or discount to sell through slow-moving inventory. A 20–30% off Lightning Deal or coupon can clear excess inventory rapidly. Better to sell at a reduced margin than to pay monthly storage fees while dragging down your IPI.

Strategy 3 — Fix stranded inventory immediately. Stranded inventory is one of the fastest IPI killers. Check Inventory > Fix Stranded Inventory weekly. Common causes: listing deleted while inventory is in FC, pricing error, listing policy violation. Fix within 48 hours of discovery.

Strategy 4 — Increase your sell-through rate by improving listing quality. A product that sells faster needs less stored inventory to meet demand, improving your storage efficiency ratio. Invest in PPC, better images, and listing optimization as IPI management tools.

Strategy 5 — Distribute inventory across multiple fulfillment channels. If you have high-volume products that are being constrained by FBA limits, consider a Multi-Channel Fulfillment (MCF) approach: keep some inventory at a 3PL and fulfill orders from your own website or other channels from there, reserving FBA capacity for Amazon orders.

Use Seller Fulfilled Prime (SFP) as a supplement. SFP allows you to offer Prime-eligible shipping for inventory you store and ship yourself (from your own warehouse or a 3PL). This does not consume FBA restock capacity. It requires maintaining very fast shipping times and meeting Amazon's strict SFP performance metrics, but it is a viable expansion valve when FBA limits bite.

Strategic ASIN splitting: some sellers split their product into multiple ASINs (e.g., different quantities or bundle configurations) to distribute inventory across separate restock limits. This is a gray area — do not create ASINs solely to circumvent limits, as Amazon may consolidate them. However, if you genuinely offer a 1-pack and a 3-pack, each has its own restock limit.

Send smaller, more frequent shipments. Instead of one large quarterly shipment, send smaller monthly replenishments. Each shipment tops up inventory without triggering excess inventory flags. This requires more frequent coordination with your freight forwarder and increases per-unit shipping costs slightly, but preserves IPI.

Prioritize high-velocity products in your FBA allocation. When you have limited restock capacity, allocate it to your fastest-selling, highest-margin products. Slow-moving or seasonal products can be moved to a 3PL with MCF fulfillment.

Q4 (October–December) is simultaneously when you need the most inventory and when Amazon is most aggressive about enforcing restock limits. Plan 90 days in advance — your Q4 FBA inventory needs to be en route from Taiwan no later than September.

Check your restock limits in August and project Q4 demand. If your limits will not accommodate your Q4 plan, begin the IPI improvement actions in July–August to give yourself 60 days to raise your score before Q4 shipments need to arrive.

Q4 storage surcharge: Amazon charges higher storage fees from October to December ($2.40/cubic foot vs. $0.87 in other months for standard-size items). This is separate from restock limits but further incentivizes precise inventory management. Sending too much inventory for Q4 is expensive in storage fees, not just IPI points.

Create a restocking calendar: map out your expected sell-through rate in Q4, your restock limit, your ocean freight lead time, and work backward to set your final Taiwan ship date. Build in a 1-week buffer for customs delays.