7 critical steps for inventory planning and fulfillment
Build a supply rhythm that reduces stockouts, lowers storage costs, and protects customer satisfaction.
Inventory planning sits at the intersection of demand forecasting, cash flow management, and operational logistics. Getting it wrong in either direction — too much or too little — costs money and erodes customer trust. Here is a seven-step framework we use with our distribution partners.
Step 1: Establish Your Demand Baseline
Start with 13 weeks of rolling sales data, adjusted for any promotional events or stockout periods that distort the baseline. Segment SKUs by velocity tier: A (top 20% of units sold), B (middle 30%), and C (bottom 50%). Apply tighter reorder logic to A-tier SKUs and less frequent ordering cycles to C-tier.
Step 2: Calculate Lead Time Accurately
Lead time is not just factory production time. It includes purchase order processing, quality inspection, port clearance, freight transit, customs, and inbound receiving at the warehouse or FBA. Map every handoff and assign average and worst-case durations to each stage.
Step 3: Define Safety Stock by SKU
Safety stock should cover demand variability during your lead time, not a flat "30 days of stock" rule. The formula: Safety Stock = Z-score × σ (demand standard deviation) × √(lead time in days). For A-tier SKUs use a 95% service level (Z=1.65); for C-tier 85% (Z=1.04).
Step 4: Set Reorder Points
Reorder Point = (Average Daily Sales × Lead Time in Days) + Safety Stock. This number should be monitored in real time, not in weekly spreadsheet reviews. Any SKU hitting its reorder point should trigger an automated purchase order or at minimum an alert to the buying team.
Step 5: Manage Seasonal Uplift
Overlay your demand baseline with historical seasonal indices. For marketplaces, Q4 typically requires 2–3× normal inventory depth for consumer goods categories. Begin build-up 10–12 weeks before peak to allow for supplier lead time and inbound receiving queues at fulfilment centres.
Step 6: Avoid Long-Term Storage Fees
At FBA, aged inventory accrues significant storage fees after 180 and 365 days. Run a monthly inventory age report and apply promotional mechanics (coupons, price reductions, bundle listings) to accelerate turns on slow-moving stock before it enters the expensive storage tier.
Step 7: Build Supplier Relationships Around Flexibility
Negotiate flexibility clauses into supplier contracts: minimum order quantity reductions for fast-turn replenishment, priority production scheduling for peak periods, and quality hold procedures that do not delay the entire shipment. These terms are worth more over 12 months than a 2% unit cost reduction.
