When should you reorder?
Operators setting low-stock thresholds for fast-moving supplies, parts, ingredients, or ecommerce inventory.
Formula and worked example
A reorder point calculator applies the reorder point formula (average daily usage × lead time in days + safety stock) to find the on-hand level that should trigger a reorder review before you stock out. Enter your average daily usage, supplier lead time, and safety stock to get a working reorder point per SKU or location.
Forecasting seasonal demand or optimizing order quantity. This calculator answers when to reorder, not how much to buy.
A part uses 12 units per day, takes 7 days to receive, and needs 36 units of safety stock. Reorder point = 12 x 7 + 36 = 120 units.
Not sure what safety stock number to use? Work it out first with the safety stock calculator.
Want the formula, a worked example, and how to set thresholds by location? Read the reorder points explained guide.
Reorder point
120
units on hand
Usage during lead time
84
units before receipt
Status
Reorder review needed
On-hand stock is 24 units below the reorder point.
Reorder point: 120 units. Lead-time demand: 84 units. Safety stock: 36 units. On-hand stock: 96 units.
Review this with Order3Check the figures behind your threshold
Review demand and delivery times when they change. Check open purchase orders before ordering more stock.
Step 01
Work through one SKU
Suppose you use 12 brackets per day, replenishment takes 7 days, and you keep 36 units of safety stock. Reorder point = (12 × 7) + 36 = 120 units. The daily rate and lead time must use the same time unit. This is an illustrative threshold, not a recommendation to buy 120 brackets.
Step 02
Check the PO already in flight
The calculator compares the shelf count with the threshold. It does not read open POs or commitments. Before buying, check inventory position: on hand + confirmed incoming stock − committed demand. With 96 on hand, 72 incoming and 12 committed, the position is 156 units. That is above the 120-unit threshold, but only rely on the incoming PO if it will arrive before you run out. A late delivery needs a separate decision.
Step 03
Use measured usage, not instinct
Pull usage from the last 60 to 90 days when possible. A one-week snapshot is noisy. A full year can hide recent demand changes. For seasonal businesses, calculate a separate reorder point for the busy season instead of averaging the year into one misleading number.
Step 04
Measure lead time from decision to shelf
Lead time starts when your team decides to reorder and ends when the stock is usable. If a PO waits two days for approval, those two days count. If receiving takes a day before items are available, that day counts too.
Step 05
Set the rule per location
A busy store, a central warehouse, and a technician truck should not share one threshold. Each location has its own usage rate and effective lead time. Calculate the reorder point where the item actually runs out. The reorder points guide covers why thresholds should vary by location and how to set them.
Order3 fit
Track the stock behind this calculation
Add your items to Order3 and track quantities by location alongside your purchase orders.
Frequently asked questions
What is the reorder point formula?
Reorder point = average daily usage x lead time in days + safety stock. The result is the stock level that should trigger a reorder review before the shelf runs empty.
Is reorder point the same as reorder quantity?
No. Reorder point tells you when to reorder. Reorder quantity tells you how many units to buy. Quantity depends on case packs, supplier minimums, freight breaks, budget, and storage capacity.
Does this calculator include open purchase orders?
No. It calculates a threshold and compares it with the on-hand count you enter. Check confirmed incoming stock, committed demand and delivery dates before creating a new PO. A low shelf count can coexist with enough stock already on order.
Should every SKU have a reorder point?
No. Start with the SKUs where stockouts hurt: high-velocity items, high-margin items, job-critical parts, clinical supplies, or items with long lead times. Add the long tail after the core list is stable.
Related
Related inventory resources
Read more about safety stock or calculate a buffer for your items.
Use case
Inventory Management
Use case
Parts Tracking
Use case
Supplies & Consumables Tracking
Feature
Low-stock alerts
Feature
Purchasing Agent
Guide
Reorder points explained: formula, examples, and how to set them
Guide
Inventory management for small business: the practical guide
Free calculator
Safety stock calculator
Definition
Reorder point
Definition
Safety stock
Definition