UK FBA Answer · Updated 2026

How do Amazon UK FBA restock limits work?

Short answer

Amazon UK uses Inventory Performance Index (IPI) — a 100-point score combining excess inventory, sell-through rate, stranded inventory, and in-stock rate — to set your individual restock limit. Score above 400-450 unlocks unlimited restocking; below that, Amazon caps your storage cubic feet per category. Most beginner UK FBA sellers operate around IPI 300-500 with category-specific caps.

Restock limits are Amazon's way of preventing slow-moving sellers from clogging their warehouses. The system feels arbitrary at first — your competitor restocks unlimited; you're capped at 50 cubic feet of beauty. The mechanic is actually transparent once you understand IPI.

What IPI actually measures

IPI = Inventory Performance Index, a 100-1000 scale (despite Amazon calling it "out of 100" in the dashboard — the multipliers are different per category). It's a weighted average of: (1) Excess inventory percentage — % of stock with >90 days of supply at current sales rate. (2) Sell-through rate — units sold ÷ average units in storage, last 90 days. (3) Stranded inventory percentage — listings with stock that can't sell (suppressed, deleted, hazmat issues). (4) In-stock rate — % of time your active SKUs were in stock and available to buy.

What unlocks unlimited restocking

Amazon UK's threshold for unlimited restocking has shifted multiple times. As of 2026, IPI 450+ unlocks unlimited restocking in most categories. IPI 350-450 gets you category-specific caps but generally workable. Below 300, you're heavily restricted and need to fix the underlying issues before scaling.

How beginners hit the limit

Common path: new seller buys 200 units of one product on first arbitrage spree, ships to FBA, only 30 sell in the first 30 days. Excess inventory % spikes, IPI drops, restock limit kicks in. Then they panic-buy 200 units of a different product, same thing happens. Spiral. The fix: smaller test orders (10-30 units of any new SKU), watch sell-through for 30-60 days, scale only the winners.

Practical IPI improvement tactics

(1) Aggressively remove or destroy stranded inventory each month — Seller Central → Inventory → Stranded Inventory → bulk action. (2) Run aggressive markdowns on >120-day stock to clear it before it becomes "excess". (3) Use FBA removal orders for slow movers below break-even — better to liquidate and reinvest than let them clog limits. (4) Improve in-stock rate on winners — set replenishment alerts well in advance of stockout dates. (5) Don't list new SKUs in bulk — test 10-30 units, see the sell-through, scale.

When restock limits matter most

Q4 (October-December) is when restock limits hurt the most. Amazon UK reduces storage capacity available to non-Premium-tier sellers by 30-50% during the run-up to Christmas, while demand is at its peak. If your IPI is sub-400 going into October, you'll be missing sales for 8-12 weeks. Build IPI in Q3 (July-September) so you're unrestricted by November.