What a replenishment cycle looks like for FBA
The replenishment cycle is the heartbeat of your FBA business. Every SKU follows this loop: you forecast how many units you’ll sell, place a PO with your supplier, wait for production, ship via ocean freight, clear customs, prep and ship to FBA, wait for Amazon to receive it, sell through the inventory, and start again.
The total cycle time determines two things: how far ahead you need to plan, and how much cash is locked in inventory at any given time. A 90-day cycle means you always have at least 90 days of capital deployed between paying the supplier and collecting Amazon payouts. For a $2M annual business with a 90-day cycle, that’s roughly $500,000 in working capital tied to inventory.
Shortening the replenishment cycle frees cash. Lengthening it (through slower suppliers, longer transit, or Amazon receiving delays) requires more capital or tighter forecasting to avoid gaps. Professional inventory management tools can automate cycle tracking and alert you when it’s time to reorder. If you’d rather not eyeball that timing, our free reorder point tool returns the exact trigger value.
Replenishment cycle formula
Example: cycle timeline for a $34 silicone mat
You sell a silicone baking mat at $34 ASP, 25 units/day, ordered from a factory in Dongguan:
| Stage | Days | Running total |
|---|---|---|
| Supplier production | 18 | Day 18 |
| Inland freight to port | 3 | Day 21 |
| Ocean transit (Shenzhen to LA) | 22 | Day 43 |
| Customs + drayage | 5 | Day 48 |
| Prep center + ship to FBA | 4 | Day 52 |
| Amazon receiving | 5 | Day 57 |
Total cycle time: 57 days.
PO quantity: 25 units/day × 57 days + 200 units safety stock = 1,625 units
PO cost (landed): 1,625 × $8.50 COGS = $13,813
Cash cycle: The supplier requires 30% deposit at PO and 70% before shipment (day 18). Amazon pays every 14 days after sale. If the order sells through in 65 days, your cash is tied up for roughly 57 + 65 – 18 = 104 days from first payment to full collection. That’s $13,813 deployed for 104 days.
If you can cut production time to 12 days by keeping safety stock at the factory, the cycle drops to 51 days and you free up 6 days of supply (150 units, $1,275 in COGS) from your required order.
How Amazon constraints shape the cycle
Amazon’s restock limits can cap how much you send per cycle. If your limit is 1,200 units but your cycle math says you need 1,625, you either shorten the cycle (more frequent, smaller orders) or route overflow through AWD and let Amazon replenish from there.
Seasonal storage surcharges also affect replenishment cycle economics. Sending a large Q4 order that sits in FBA for 45 days before peak selling begins racks up storage fees that eat into margin. Timing the cycle so inventory arrives just-in-time for demand is worth the planning effort. Amazon’s FBA program rewards sellers who keep their replenishment cycle tight with better IPI scores and higher restock limits.
Common mistakes
- Measuring cycle time from PO to port, not PO to available-for-sale. The last mile (prep, FBA shipping, Amazon receiving) can add 7-14 days. If you plan around port arrival, you’ll consistently run low before new stock goes live.
- Ignoring the cash cycle. A 90-day replenishment cycle with 30-day payment terms means 60+ days of cash exposure per PO. Sellers who don’t model this run out of cash before they run out of inventory.
- Running one cycle length for all SKUs. Fast-selling, low-cost items might warrant shorter cycles with smaller orders. Slow-moving, expensive items might benefit from longer cycles with larger batches to hit MOQ price breaks.