XBKit·Amazon

Safety Stock Calculator

Calculate the buffer inventory you need to prevent stockouts during demand spikes or supplier delays.

Sales Velocity
Lead Time

Lead time = factory production + transit to FBA/warehouse. Use your worst-case delays for max lead time.

Formula
Safety Stock=(Max Sales × Max Lead Time)(Avg Sales × Avg Lead Time)
  • Covers demand spikes + supplier delays
  • Add to your reorder point
  • Review quarterly as velocity changes

How to Use

  1. 1

    Enter max and average daily sales

    Input your maximum daily sales (e.g., peak day in the last 90 days) and your average daily sales. The difference drives your safety stock requirement.

  2. 2

    Enter max and average lead time

    Input the longest lead time you have experienced from your supplier and your typical lead time. Variability in lead time is a key risk factor.

  3. 3

    Review recommended safety stock

    See the recommended safety stock level in units. This is the buffer to hold above your reorder point.

  4. 4

    Plan your inventory levels

    Add the safety stock to your reorder point (from the Reorder Point Calculator) for a complete inventory plan.

Frequently Asked Questions

What is safety stock?

Safety stock is extra inventory kept as a buffer against uncertainty — unexpected demand spikes (e.g., a viral product moment) or supplier delays (holiday factory closures, port congestion, QC holds). Without safety stock, any variance above average can cause a stockout.

How much safety stock do FBA sellers typically hold?

FBA sellers commonly hold 2–4 weeks of safety stock. For products with long lead times (60+ days from China) and volatile demand, 4–6 weeks is safer. The right amount depends on your demand variability and supplier reliability.

Does holding more safety stock hurt my IPI score?

Amazon's Inventory Performance Index (IPI) considers excess inventory. Holding 6+ months of stock without sales can reduce your IPI score and lead to storage restrictions. Balance safety stock with sell-through rate — enough to prevent stockouts without creating an overstocking penalty.

What is the difference between safety stock and reorder point?

Safety stock is the minimum buffer inventory you should never dip below. The reorder point (ROP) is the stock level that triggers a purchase order. Reorder Point = (Average Daily Sales × Lead Time) + Safety Stock. Safety stock is a component of the reorder point, not the same thing.

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