How Much Stock to Send to Amazon Before Q4 2026

If you are reading this in the second half of August, the decision is already in front of you. Amazon's first Q4 inbound deadline is about three weeks away, and the number you commit to now is the number you live with until January.

Most advice on this is some version of "don't send too much, Q4 storage is expensive." That advice is aimed at the wrong fee. Peak storage is real but survivable. The fee that actually punishes an over-send doesn't arrive until the following summer, and by then the stock is unsellable at full price anyway.

Here are the dates, and then the part that matters.

The deadlines, and the one nobody checks

Amazon moved every inbound cutoff earlier this year. For the US:

Prime Big Deal Days (October)

• September 2 — Amazon Warehousing and Distribution (AWD)
• September 9 — FBA, minimal shipment splits
• September 16 — FBA, Amazon-optimized shipment splits

Black Friday and Cyber Monday

• October 14 — AWD
• October 21 — FBA, minimal shipment splits
• October 28 — FBA, Amazon-optimized shipment splits

Read those two FBA lines again, because this is the detail that gets missed: your deadline depends on how you split the shipment. It's a week apart. Nobody tells you this when you're building the shipping plan.

Minimal shipment splits means you consolidate into as few destinations as possible. It's simpler, your freight forwarder prefers it, and you pay Amazon's inbound placement fee for the privilege. Amazon-optimized splits means you send to wherever Amazon tells you, across more locations, and the placement fee drops or disappears.

So the "simpler" option costs you the placement fee and seven days of calendar. If you're staring at a container that will clear customs around September 8th, that week decides whether your stock is live for Prime Big Deal Days or not. Choosing Amazon-optimized splits is often the difference — and it's cheaper. Check which split type your shipping plan actually defaulted to before you assume you have until the 16th.

Also worth knowing: these dates are arrival deadlines at Amazon, not ship-by dates. Carrier receive-to-checkin can run one to two weeks in peak season. Work backwards from the deadline, not forwards from today.

Peak fees, in the correct proportion

Two things go up on October 15, 2026, and run through January 14, 2027:

• Holiday peak fulfillment fees, averaging about $0.32 per unit above standard rates
• A 3.5% fuel and logistics surcharge, applied on top

Storage moves separately: standard-size monthly storage jumps to roughly $2.40 per cubic foot for October, November and December, against well under a dollar for the rest of the year. Roughly a threefold increase, which is where the "don't over-send" panic comes from.

Now here's the correction. Monthly storage is charged on your average daily cubic feet, not your peak. Stock that lands October 1st and sells through by early December pays that rate on a shrinking pile, for two or three months. On a product doing any real volume, that is small money — often a few cents a unit. It is not the reason to under-order.

The peak fulfillment fee is likewise a fixed, knowable cost. Roughly $0.32 plus 3.5% on the fulfillment portion. You can price for it. Most sellers can absorb it without touching their list price.

If those were the only Q4 costs, the right answer would be to send plenty and stop worrying.

The fee that actually punishes an over-send

The aged-inventory surcharge is a monthly charge on units that have been sitting in a fulfillment centre a long time, and it is charged on top of normal storage. It starts at 181 days. The bands for standard-size stock look roughly like this:

• 181–210 days: $0.50 per cubic foot
• 211–240 days: $1.00
• 241–270 days: $1.50
• 271–300 days: $5.45

That is not a typo. Between day 270 and day 271, the rate goes up more than threefold. It is the steepest cliff in the entire FBA fee schedule, and it is the single most under-modelled number in Q4 planning.

Now put your calendar against it. Stock that arrives for the September 16 cutoff crosses 271 days in mid-June 2027. Stock that lands for the October 28 Black Friday cutoff crosses it in late July 2027.

So the true cost of over-sending isn't the $2.40 you pay in November. It's that your Q4 leftovers start bleeding at $0.50 a cubic foot from around late April 2027, and then hit $5.45 in the summer — while you're simultaneously discounting them, paying return processing, and taking up the capacity you need for the next Q4 order.

One more wrinkle: for the 181-to-270 day bands, clothing, shoes, bags, jewellery and watches are excluded. Those categories only start paying from 271 days. If you sell apparel, your first aged-inventory charge and the cliff are the same event.

The squeeze from the other side

The obvious response is to run lean. Amazon charges you for that too.

The low-inventory-level fee applies when your historical days of supply falls below 28 days — measured on both your 30-day and 90-day figures. It runs from about $0.32 to $0.97 per unit on standard sizes, and can exceed $2.00 on bulky items. It is charged per unit shipped, so it lands on your best sellers at the exact moment they're selling best.

The trap inside it is arithmetic. Days of supply is units divided by your recent sales rate. In Q4 your sales rate climbs steeply — so your days of supply falls even if you haven't sold a single extra unit yet. Sellers get hit by this fee in November having never changed their stock position. The denominator moved.

There are exemptions worth checking against your catalogue: products selling under 20 units a week, products enrolled in FBA New Selection, grocery, and stock replenished automatically from AWD. Since January 2026 the fee is calculated per FNSKU rather than per parent ASIN, so a variation-heavy listing that used to pass as a group can now fail child by child.

So what's the number

You are aiming at a corridor, not a target. Above 28 days of supply through the whole quarter, and close to zero by roughly February.

In practice that means:

1. Forecast per FNSKU, not per parent. The fee is assessed there now, and your sizes and colours do not sell evenly.
2. Use last year's Q4 daily rate, not your current one. Your August run rate will understate November by a wide margin.
3. Aim to be near-empty by early February, not by December 31. January is a genuinely good selling month, and it keeps you clear of the 181-day band.
4. Hold your buffer in AWD, not FBA. AWD storage is cheaper, replenishment into FBA counts toward the low-inventory exemption, and the aged clock behaves differently. This is the single most useful structural move available.
5. Split the order. Landing everything in September maximises both peak storage and aged exposure. A second wave arriving late October is usually cheaper.

If a product's honest forecast says you'll still be holding meaningful stock in April, order less than the forecast. The cliff is worse than the stockout.

Where this goes wrong quietly

None of this is hard maths. It goes wrong because the numbers live in four different places — sales velocity in one report, days of supply in another, storage and aged-inventory charges buried in a settlement file that arrives weeks later. By the time an aged-inventory surcharge shows up as a line item, the decision that caused it is nine months old.

That's the gap Seller Sphere was built to close: your true per-product profit with every one of these fees attributed to the product that incurred it, days of supply tracked per FNSKU against the thresholds that actually trigger charges, and an AI assistant that flags the ones drifting toward a cliff while you can still do something about it.

You can see how it works here. If you only take one thing from this article, take the calendar check: work out today which of your products will still be sitting in a fulfilment centre next June.

Frequently asked questions

When is the Amazon FBA inventory deadline for Q4 2026? For Prime Big Deal Days: September 2 for AWD, September 9 for FBA using minimal shipment splits, and September 16 for FBA using Amazon-optimized shipment splits. For Black Friday and Cyber Monday: October 14 for AWD, October 21 for minimal splits, and October 28 for Amazon-optimized splits. These are arrival deadlines at Amazon, not ship-by dates, so allow one to two weeks for carrier receiving during peak.

Why do two different FBA deadlines exist? Because the cutoff depends on how your shipment is split. Amazon-optimized shipment splits send stock to more locations as Amazon directs and get roughly a week longer, while minimal shipment splits consolidate into fewer destinations, carry an inbound placement fee and have the earlier deadline. Check which one your shipping plan defaulted to before assuming you have the later date.

How much are Amazon's Q4 storage fees in 2026? Standard-size monthly storage rises to around $2.40 per cubic foot for October, November and December, against well under a dollar for the rest of the year. It is charged on your average daily volume rather than your peak, so stock that sells through quickly pays far less than the headline rate suggests. Pull your current rates from Seller Central, as Amazon revises them.

What are the 2026 holiday peak fulfillment fees? Holiday peak fulfillment fees apply from October 15, 2026 through January 14, 2027, averaging about $0.32 per unit above standard rates, with a 3.5% fuel and logistics surcharge applied on top. The per-unit increase is unchanged from the previous cycle.

What is the aged-inventory surcharge and when does it start? It is a monthly charge on FBA units that have been in a fulfillment centre for 181 days or more, billed in addition to normal storage. For standard-size stock it runs roughly $0.50 per cubic foot at 181–210 days, $1.00 at 211–240, $1.50 at 241–270, and jumps to about $5.45 at 271–300 days. Clothing, shoes, bags, jewellery and watches are excluded from the bands below 271 days.

What is the low-inventory-level fee and how do I avoid it in Q4? It applies when your historical days of supply falls below 28 days on both the 30-day and 90-day measures, and costs roughly $0.32 to $0.97 per unit shipped on standard sizes. It catches sellers in Q4 because rising sales shrink days of supply even when stock levels haven't changed. Exemptions include products selling under 20 units a week, FBA New Selection enrolments, grocery, and stock auto-replenished from AWD.

Should I send everything to FBA or hold stock in AWD? Holding your buffer in Amazon Warehousing and Distribution is usually cheaper: storage costs less, automatic replenishment into FBA counts toward the low-inventory-level fee exemption, and it keeps units out of the FBA aged-inventory clock. Send enough to FBA to stay above the days-of-supply threshold and replenish from AWD rather than committing the whole order to a fulfillment centre in September.