Amazon FBA Capacity Limits in Q4: A Cash Planning Guide

Your FBA capacity limit tells you how much inventory Amazon will let you hold. It does not tell you whether you can afford to fill it. For a December restock, the binding constraint is usually cash: the supplier gets paid in November, Amazon charges peak-rate storage and fees on the way in, and the money from the units you sell in late December mostly lands in your bank in January. Plan the inbound shipment against a dated cash schedule first, then check it against the capacity limit, then decide whether buying extra capacity is worth it.

How the capacity limit works in 2026

Amazon moved to a single monthly capacity limit per storage type in March 2023, measured in cubic feet, according to its announcement on sell.amazon.com. Seller Central's capacity limits page still describes the same structure: one limit for each storage type per month, with estimates shown for the next three months in the Capacity Monitor at the bottom of the FBA dashboard. Amazon's Capacity Manager help page says estimated limits for the upcoming period are confirmed in the third or fourth week of the month. For a seller planning December, that means the confirmed December number arrives in late November, after most purchase orders for December stock have already been placed and paid.

Two details matter for the calendar.

Capacity Manager. If the limit is too small, you can request more for a future month at a reservation fee per cubic foot that you set. Amazon grants requests starting from the highest fee and works down. The granted capacity can be available up to a month before the requested period, so you can ship ahead. Requests cannot be made for the current month.
Performance credits. Per the same help page, you earn $0.15 of credit for every $1 of FBA sales generated using the extra capacity, prorated by the share of your total limit the increase represents. Credits can offset up to 100 percent of the reservation fee. The fee, net of credits, is charged after the period ends. December's bill shows up in early January.

Exceed your limit without an increase and Amazon can charge FBA inventory overage fees. Amazon publishes those rates in Seller Central; check the current figure there before you plan to run over.

The fees that move with the calendar

Q4 inbound has its own fee schedule, and every line on it has a date attached.

Holiday peak fulfillment fees apply to units shipped from October 15, 2026 through January 14, 2027, per Amazon's Holiday 2026 Seller Central announcement from July 2026. Amazon put the average increase over non-peak rates at $0.32 per unit, with the 3.5 percent fuel and logistics surcharge applied on top.
Monthly storage for standard-size items runs $2.40 per cubic foot in October through December and $0.78 per cubic foot January through September, on Amazon's 2026 rate card. A unit that arrives December 1 and sells January 10 pays the high rate for December and the low rate for ten days of January.
Inbound placement service fee. If you choose minimal shipment splits, Amazon's fee page lists per-unit charges by size and weight, for example $0.20 to $0.40 for a large standard item of 12 ounces or less as of January 15, 2026. Amazon-optimized splits carry no placement fee but send cartons to more locations. Amazon's own worked example notes the fee is charged 45 days after the shipment is first received, so a late November receipt is billed in January.
Low-inventory-level fee. Amazon's 2026 schedule charges this per unit when historical days of supply drop below 28. Running out of room and running too lean both cost money.

The cash problem is timing: the charges arrive on different dates from the sales that pay for them.

A worked example: one December restock

Illustrative numbers. Take a seller with a standard-size kitchen product that sells for $29.99. Each unit occupies 0.125 cubic feet, so eight units fill a cubic foot. Landed cost is $9.50 per unit. The estimated December standard-size limit is 2,000 cubic feet, and the seller's forecast says December needs 2,500 cubic feet on hand at peak. The gap is 500 cubic feet, or 4,000 units.

The purchase. 4,000 units at $9.50 is $38,000 of landed cost: $35,600 to the supplier and $2,400 of freight. The supplier took a 30 percent deposit in September ($10,680) and wants the balance of $24,920 at shipment on November 10. The freight invoice is due November 12.

The capacity request. The seller asks Capacity Manager for 500 cubic feet in December with a maximum reservation fee of $2.00 per cubic foot, a figure chosen for this example. Worst case, the fee is 500 times $2.00, or $1,000. The increase is 500 of a 2,500 cubic foot total, a ratio of 0.20.

If December standard-size FBA sales reach $180,000, prorated sales are $180,000 times 0.20, or $36,000. Credits are $36,000 times 0.15, or $5,400. The $1,000 fee is fully offset.
If December sales fall to $25,000, prorated sales are $5,000 and credits are $750. The seller pays $1,000 minus $750, or $250, in early January.

The reservation fee is the small number here. The inventory is the large one.

The inbound fees. The seller picks minimal shipment splits to save on freight. At an illustrative $0.30 per unit, inside Amazon's published range, placement is 4,000 times $0.30, or $1,200. Received November 25, billed about January 9.

The sales. Say 2,400 of the 4,000 units sell in December. Referral fee at 15 percent is $4.50 per unit. Use an illustrative peak fulfillment fee of $5.10. Net per unit is $29.99 minus $4.50 minus $5.10, or $20.39. Across 2,400 units that is $48,936.

Storage. Average December volume of these extra units is about 300 cubic feet as they sell down. At $2.40, December storage is $720. The 1,600 units left on January 1 occupy 200 cubic feet; if they stay all of January, storage is 200 times $0.78, or $156.

The cash calendar. Under Amazon's standard reserve policy, funds become available for disbursement seven days after delivery (DD+7). Amazon's payments guide on sell.amazon.com says accounts generally settle every two weeks and that a disbursement can take up to five business days to reach the bank. Units delivered December 10 become available December 17. Units delivered December 22 become available December 29, go out on the next settlement, and reach the bank in January.

Put the dated flows side by side:

September: $10,680 out (deposit)
November 10 to 12: $27,320 out (balance plus freight)
Mid to late December: roughly half of the $48,936 arrives, about $24,500
Early to mid January: the other $24,400 arrives, while $1,200 placement, $720 storage, and up to $250 net reservation fee go out

From November 10 to mid-December, the seller is $38,000 down on this shipment alone, counting the September deposit, before any ad spend. December's P&L will show a healthy margin. The December 15 bank balance will not.

Turning the example into a plan

Work backward from the bank, not forward from the forecast.

Date every outflow. Supplier balance, freight, duty, and the inbound fees with their 45-day lag. Put the reservation fee in the month after the period.
Date every inflow by channel. Delivery date plus seven days, then the settlement cycle, then bank transit. If you sell on Walmart or Shopify too, their schedules differ, so date each channel's payouts separately.
Find the low point. The lowest projected balance between the supplier payment and the January payouts is the number that decides how much you can buy. The broader method is in why profit is not cash.
Then size the shipment to the limit. If the cash supports 4,000 units but capacity allows 2,000, decide whether the reservation fee risk is acceptable. If capacity allows 4,000 but cash supports 2,500, capacity is irrelevant.
Check sell-through honestly. Units that miss December carry storage, aged inventory exposure, and a slower payout into Q1. The Q4 reorder point method covers the velocity side.

Where your books help, and where they cannot

This plan depends on three numbers most sellers do not have to hand: current landed cost per unit, actual sell-through by SKU, and what is physically at Amazon versus in transit. ConnectBooks reconciles the transactions and fees in each Amazon settlement, referral, fulfillment, storage, and placement charges included, and syncs them to QuickBooks or Xero as summarized entries or item-level detail. On the inventory side, stock is tracked by warehouse, transfers sit as in-transit until received, FIFO valuation carries landed cost per unit, and the restock report works from sales history and velocity with lead times and inbound stock factored in.

That data gives you the inputs. It does not give you Amazon's December confirmed limit before Amazon publishes it, the reservation fee other sellers are bidding, or a guarantee that December demand matches the forecast. Those stay judgment calls. The cash schedule is how you make them with your eyes open.

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