Q4 inventory planning is a backward-scheduling exercise: December demand is served by stock that cleared receiving in November, which was ordered in September or earlier, on lead times that stretch exactly when everyone else is ordering too. The sellers who look lucky in December built a calendar in August. Here is the calendar, and the sizing and operations discipline that go with it.
The backward calendar
Work each deadline from the one after it:
- Sales window: your peak, BFCM through mid-December for most catalogs, with marketplace shipping cutoffs ending it earlier than the 24th.
- Stock-ready date: everything receivable should be shelved BEFORE peak starts, receiving during peak steals packing labor.
- Order deadline per supplier: stock-ready date minus measured lead time minus receiving time minus a Q4 slippage margin (ports, carriers, and factories all run slower; pad by 20-30 percent of lead time).
- FBA inbound deadline, if applicable: Amazon publishes hard inbound cutoffs for holiday eligibility and warehouses congest weeks earlier; FBA stock planning needs its own earlier lane.
- Forecast freeze: the seasonal buy is sized before the order deadline, which means the forecasting happens in late summer.
Miss a deadline and the choice is air freight (margin) or stockout (revenue); the calendar exists so you choose neither.
Sizing the seasonal buy
- Start from last year’s shape: per SKU (or category for young catalogs), what multiple of baseline did November and December run? Seasonal indices formalize it.
- Apply this year’s trend: a SKU growing 30 percent year-round reasonably grows its Q4 too; a fading one does not deserve last year’s buy.
- Rank the bets with ABC eyes: A-items get deep coverage, they cannot stock out during the one month that decides the year. The C-tail gets minimal seasonal exposure; December is a terrible month to guess on the tail.
- Cap every buy with the January question: if the season underperforms, what is this SKU’s exit, evergreen sell-through, planned clearance, or dead stock? Buys without exits become February’s storage bill.
Operations at peak velocity
Q4 velocity compresses every operational weakness:
- Sync gaps become incidents. The 15-minute interval that survives March produces double-sells during a BFCM hour. Real-time propagation and per-channel sync-health checks are pre-peak items, verify in October, trust in November.
- Buffers earn their keep. Raise safety buffers on thin, fast SKUs before traffic arrives; the last-two-units race is a Q4 specialty.
- Watch cover daily. Days-of-cover forecasts at peak velocity are your reorder-or-not dashboard for the January-adjacent window: late-season reorders must clear the is-there-time test.
- Protect the metrics. Marketplace handling-time promises tighten under volume; a defect earned in December drags visibility into the new year.
The January exit
Plan the exit in October: which SKUs carry into evergreen at normal cover, which get staged clearance starting late December, which bundle into new-year offers. Executing a pre-decided exit takes a week; improvising one takes a quarter.
Common questions
When should Q4 planning actually start?
Forecasting in July-August, orders placed by early September for ocean-freight supply chains, later only for domestic or fast suppliers. If you are reading this in October, prioritize domestic-lead-time SKUs and buffer what you already hold.
How much extra stock should I carry for BFCM?
What last year’s multiple times this year’s trend says, per SKU, bounded by your exit plan. The honest answer is a computation, not a percentage folklore.
Should I raise prices during Q4?
Demand-driven adjustments within your per-channel rules are normal; gouging your own list is remembered. Deliberate, rule-driven, reversible.
What about returns season in January?
Plan receiving capacity for it, and count returns back in properly, January’s phantom stock discrepancies are usually December’s returns handled loosely.
Peak-proof the stack before the traffic
Real-time sync, buffers, and sync-health checks, tightened once, before November does it for you, with daily cover forecasts on the plans above. From $49/month with unlimited orders. See pricing.