Inventory Reorder Point Calculator
Enter your average daily sales, supplier lead time, safety stock buffer, and units on hand to reveal the exact stock level that should trigger your next purchase order, plus your days of cover and restock timing.
Reorder Point Inputs
A reorder point is the inventory level that triggers a new purchase order so you receive stock before running out. Calculate it by multiplying your average daily units sold by the total of supplier lead time days plus safety stock days.
What the Reorder Point Calculator Does
The Inventory Reorder Point Calculator tells you exactly when to place your next purchase order so replacement stock arrives before your shelves go empty. By combining your sales velocity, supplier lead time, and a safety stock buffer, it converts guesswork into a precise trigger quantity. The tool also reports your current days of cover and estimates how many days remain until you hit that trigger, helping you avoid both stockouts and dead capital tied up in excess inventory.
Who Should Use This Tool
Amazon & Marketplace Sellers
FBA and marketplace sellers timing restocks around long overseas lead times so listings never go out of stock and lose ranking.
Shopify & DTC Store Owners
Direct-to-consumer brands balancing cash flow against stockout risk by ordering only when inventory hits the calculated trigger.
Wholesale & Distributors
Operators managing many SKUs who need a repeatable, per-item rule for when a replenishment purchase order should fire.
Print-on-Demand & Kitting Brands
Sellers holding blanks or components who must reorder raw materials ahead of production runs and seasonal demand.
Reorder Point & Safety Stock Terms Defined
Your typical sales velocity per day, ideally averaged over a recent 30 to 90 day window.
The number of days between placing a purchase order and having sellable stock back in your warehouse.
Extra buffer inventory, expressed in days of sales, that protects against demand spikes and shipping delays.
How many days your current units on hand will last at your average daily sales rate.
Reorder Point Formula Breakdown
When your units on hand fall to or below the reorder point, it is time to place a new order. Above that level, the calculator estimates the days remaining before you reach the trigger, giving you a clear planning runway.
Worked Example: Amazon FBA Restock
A kitchenware brand sells 12 units per day of a silicone spatula set. Its overseas supplier plus freight and FBA check-in take 21 days, and the brand wants a 10 day safety buffer. It currently has 400 units on hand.
Reorder Point vs. Days of Cover
Days of cover answers a backward-looking question: how long will my current stock last? The reorder point answers a forward-looking one: at what stock level must I act so the next shipment lands in time? A healthy operation watches both. Days of cover flags slow movers and overstock, while the reorder point protects your best sellers from going dark during a long replenishment cycle.
Common Reorder Point Errors
Frequently Asked Questions
How much safety stock should I carry?
Many sellers set safety stock at 20% to 50% of their lead time, so a 21 day lead time might carry a 5 to 10 day buffer. Increase it for volatile demand or unreliable suppliers, and trim it for steady sellers with dependable shipping.
What daily sales figure should I enter?
Use a recent average, typically the trailing 30 to 90 days, and adjust upward if you are heading into a known peak season or a promotion that will lift velocity.
Does the reorder point tell me how much to order?
No. The reorder point is a timing trigger for when to order, not an order quantity. Pair it with an economic order quantity or a target days-of-cover figure to decide how many units to buy on each purchase order.
Why does my status say to reorder now?
The reorder-now alert appears when your units on hand are at or below the reorder point, meaning a new order placed today may only just arrive before you run out. Place the purchase order immediately to protect against a stockout.
MerchSites tools and guides are written and reviewed by ecommerce practitioners. Calculations are cent-accurate estimations based on reported platform fees and standard formula math.