Your FBA capacity limit is the total inventory you are allowed to keep at Amazon, measured in cubic feet and set separately by storage type. Amazon updates it monthly through the Capacity Monitor in Seller Central.
When your used cubic feet reach your confirmed limit, Amazon blocks you from creating new shipping plans until usage drops, and can charge overage fees. Both on-hand stock and inbound shipments count, so you can hit the wall before your warehouse even looks full.
We watch your cubic-foot utilization, time your inbound so you do not tip over the limit, keep IPI inputs healthy so your limit grows, and handle capacity requests when you need more room. Limits and thresholds are set by Amazon and can change.