Stop Reordering When It "Looks Low." Calculate the Exact Trigger.

Deciding to reorder because inventory looks low is not a replenishment method. It is a guess with a deadline attached.

This free calculator helps Amazon sellers turn three numbers into one clear trigger:

• Expected daily demand, weighted for Q4 if you want it
• Total operational lead time, built stage by stage
• Safety stock sized to this SKU's real risk

The result is your reorder point: the inventory level where you place the next order. Reach it, and replenishment becomes a rule instead of a scramble.

What You'll Get Inside the Calculator

• A live reorder point that updates as you change any input
• A weighted-demand option so a quiet summer average does not undercut your Q4 plan
• A lead-time builder that captures the full journey from PO to sellable inventory, not just the factory quote
• A normal-versus-peak view that shows exactly how many units earlier you need to trigger when demand climbs

Built for Sellers Heading Into Peak

If you have sorted your SKUs and know what to fund, the reorder point is what protects that plan. It is especially useful for sellers who need to:

• Time Q4 purchase orders against real lead times, not optimistic ones
• Adjust triggers as demand accelerates into peak
• Set safety stock deliberately instead of "whatever number feels safe"
• Replace "keep an eye on it" with a calculated threshold per SKU
• Build a habit they can repeat every quarter instead of a once-a-year fire drill

Download the Free Calculator

The Real Trigger, Not a Guess
Turn demand, lead time, and safety stock into one inventory level that tells you exactly when to reorder, SKU by SKU.

Lead Time You Can Actually Trust
Build total lead time from every real stage: production, freight, customs, prep, delivery, and receiving. The number on the supplier quote is rarely the number that matters.

A Trigger That Moves With Peak
See your normal reorder point and your peak-season reorder point side by side, so you fire early enough to survive the demand curve instead of chasing it.