STR

 STR is one of Amazon’s core retail and inventory health metrics.
 It shows the speed and effectiveness of inventory movement, helping vendors and sellers understand demand strength, forecasting accuracy, and replenishment needs.

A high STR means products are selling well relative to available inventory.
 A low STR indicates overstock, weak demand, or poor visibility.

Formula:Where:

• Shipped Units = total units shipped to end customers
• Customer Returns = units returned and deducted from demand
• On Hand Units = starting inventory at Amazon
• Received Units = inbound inventory added during the period

What STR Tells You:

• Inventory velocity
• True customer demand
• Whether Amazon has too much or too little stock
• Impact of marketing and visibility (ads, SEO, promotions)
• Relationship between replenishment and sales performance

Why STR Matters for Amazon:

• Helps identify overstock or understock risks
• Indicates whether a product deserves more FC space
• Affects purchase order decisions for 1P vendors
• Supports fulfilment and forecast accuracy

Why STR Matters for Vendors and Sellers:

• Identifies fast movers vs. slow movers
• Helps optimise reorder quantity and timing
• Signals whether a listing needs SEO, ads, or price adjustments
• Influences profitability (low STR increases storage costs)
• Helps plan event readiness (Prime Day, Q4, seasonal spikes)

Benchmarks:

• High STR: Healthy demand, fast turnover
• Low STR: Overstock, weak visibility, or mispriced item

Example:
A vendor analyzes STR for a blender during Q1:

• Shipped: 3,200 units
• Customer returns: 200 units
• Starting inventory: 2,000 units
• Received during period: 2,000 units
• This means the product sold through 75% of its available inventory.

Common Actions Based on STR:

• Low STR: lower price, improve ads or content, reduce POs, or run promotions
• High STR: increase POs, raise price slightly, or expand variations

Why It Matters:
STR helps determine whether inventory levels align with actual demand and whether products are moving efficiently through Amazon’s network.

In short:
STR (Sell-Through Rate) measures the percentage of available inventory sold within a selected period, showing how effectively and quickly stock converts into customer shipments.