FBA inventory planning — replenishment timing, safety stock, IPI score optimization, stranded inventory recovery
Supported platforms: Amazon (United States, United Kingdom, Germany, Canada, Japan, Australia, and all marketplaces).
How to use
帮我处理亚马逊库存管理。
Features
- FBA inventory planning
- Replenishment timing
- Safety stock
- IPI score optimization
- Stranded inventory recovery
How it works
Step 1: Gather information from the user's message — product, platform, current situation, and goals.
Step 2: Ask all follow-up questions at once in multiple-choice format. Allow shorthand answers (e.g., "1b 2c 3a").
Step 3: Use the frameworks and methodologies below to conduct research and analysis.
Replenishment timing model
Replenishment point = average daily sales × (procurement lead time + shipping time + Amazon inbound time + safety buffer days)
- Average daily sales: Based on a 30-60 day rolling average to avoid short-term fluctuations.
- Procurement lead time: Confirm with the supplier (varies by supplier).
- Shipping time: Sea freight 30-45 days, air freight 5-10 days.
- Amazon inbound time: Usually 5-10 business days, may extend to 2-3 weeks during the Q4 peak season.
- Safety buffer: 20-30% of the total replenishment cycle to handle uncertainty.
Safety stock calculation method
Safety stock = service level factor × demand standard deviation × √replenishment cycle
Key factors:
- Demand standard deviation: Reflects sales volatility.
- Replenishment cycle: Reflects supply chain response speed.
- Service level target: 95-98% recommended.
- Stable products = lower safety stock. Seasonal/volatile products = higher safety stock.
- Also consider supplier delivery reliability, logistics uncertainty, and Amazon inbound delays.
IPI score optimization mechanism
IPI (Inventory Performance Index) ranges from 0-1000, based on four dimensions:
- Excess inventory score: Proportion of remaining inventory.
- Sales turnover rate: Sales volume relative to inventory.
- Stranded inventory percentage: Inventory without an active offer.
- Inventory defect rate: Inventory missing sellable information.
Impact: A score below the 500 threshold = FBA storage limits imposed, cannot be recovered until the next quarterly assessment.
Optimization actions:
- Reduce excess inventory through promotions or clearance deals.
- Improve turnover rate by increasing sales or reducing inventory.
- Fix stranded inventory by resolving listing issues.
- Complete missing product information to reduce inventory defects.
Stranded inventory identification and recovery
Common causes of stranded inventory:
- Listing blocked or deactivated.
- Incomplete/inaccurate product information.
- Policy violation.
- ASIN was merged under the wrong parent listing.
Recovery: Use Amazon's "Fix Stranded Inventory" tool to identify the cause and take targeted corrective action. Stranded inventory continues to incur storage fees but generates no sales.
Seasonal Inventory Planning
- Q1-Q2： Storage capacity is relatively ample, and IPI pressure is low. It is a good time to optimize inventory efficiency.
- Q3-Q4 (peak season): Amazon tightens storage limits, and IPI becomes critical. Clear backlog inventory and improve IPI before Q4.
- Q4 planning: Inventory for October-December needs to arrive in August-September via ocean freight to account for possible delays.
- Q1 (off-season): Control the replenishment pace and clear the previous year's backlog inventory.
Data Sources
- No external data dependencies. Based on supply chain management theory (EOQ model, service level theory) and Amazon FBA policy documents.
- User-provided: sales velocity data, shipping time, supplier lead time, current inventory status.
Limitations
- Sales forecast uncertainty: Multiple uncontrollable factors affect Amazon sales — competitor actions, algorithm changes, seasonal demand, disruptions. New products are especially difficult to forecast.
- Supply chain delay risk: Actual delays may exceed calculations. Port congestion, customs inspections, and slow warehouse receiving during peak season can all cause stockouts, despite careful planning.