Reorder Point & Safety Stock Simulator
Calculate the exact inventory threshold to trigger supplier purchase orders before stockouts occur, accounting for lead time variance and supplier cash terms.
Sales Velocity & Lead Times
Determine the exact stock threshold to issue a new purchase order without tying up excess cash.
Total landed cost per unit including manufacturing, international freight, and customs.
Exact Reorder Point (ROP)
Your current stock (850) is at or below the reorder point. Place a purchase order now so goods arrive before stockouts.
Days of Stock Left
34d
At 25 units/day
PO Working Capital
$27,000
To produce 1,500 units
A calculator models one SKU in isolation. In reality, sales velocity fluctuates across dozens of products. Margain connects to your Shopify inventory and daily sales velocity to automatically project reorder dates across your entire catalog before stockouts occur.
How the Math & Economics Work
Understand the exact equations, managerial accounting rules, and unit economics governing these metrics in modern e-commerce.
Lead Time Demand covers all customer orders expected to occur while your factory manufactures and ships new inventory. Safety stock acts as an operational cushion against supplier delays, port congestion, or sudden sales surges.
Rolling 30-day baseline
Factory to warehouse dock
25 units × 45 days
Buffer for logistics delays
Manufacturing + freight + customs
When inventory reaches 1,500 units, trigger your purchase order immediately to receive goods before safety stock is breached.
The Supplier Payment Milestone Cash Float
Inventory cash requirements rarely occur in a single transaction. Factories typically demand a 30% upfront deposit to initiate production, and the remaining 70% upon bill-of-lading (B/L) release before shipping. Operators must model this staged cash outflow against daily sales collections to avoid operating liquidity squeezes.
Frequently Asked Questions
Automate Inventory Velocity with Margain Commerce Engine
Connect your Shopify catalog to Margain to continuously sync inventory levels, monitor daily SKU run rates, and forecast reorder dates before stockouts disrupt cash flow.
Related Guides & Playbooks
Deep-dive operational frameworks explaining the unit economics, cash cycles, and marketing attribution behind this calculator.
The Pareto Principle in E-Commerce: How to Identify and Cut Cash-Drain SKUs
80% of your profit comes from 20% of your products. Learn how to use SKU-level contribution margin analysis to identify unprofitable products and prune your catalog.
The Reorder Point Formula: How DTC Brands Balance Lead Times and Working Capital
Master the reorder point formula for e-commerce, calculate safety stock buffers, and learn how to manage supplier cash flow milestones without running out of inventory.
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