Inventory reorder point calculator
Find out when to reorder, how much safety stock to keep, and how much to order at a time. Free and private.
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Small Shop Inventory & Reorder Tracker (Excel)
Want a spreadsheet that does this for every product and flags what to reorder? Log stock in and out; see current stock, what to reorder, what your stock is worth and your gross profit.
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How it works
Reorder point = average daily sales × lead time + safety stock. Safety stock is either days of sales or z × daily variation × √(lead time). Economic order quantity = √(2 × yearly demand × order cost ÷ yearly holding cost per unit). See the guide with a worked example.
Common questions
What is a reorder point?
The stock level at which you place a new order so that the new stock arrives before you run out: demand during the supplier's lead time plus a safety buffer.
How is safety stock calculated here?
Either as a number of days of sales you want to keep as a buffer, or, if you enter the day-to-day variation in your sales and a service level, as z x variation x sqrt(lead time). Both are standard textbook methods.
What is the economic order quantity?
The order size that minimises the sum of ordering costs and holding costs for a year: sqrt(2 x yearly demand x cost per order / yearly holding cost per unit). It assumes steady demand.
Is this right for every product?
It is a good starting point for items with steady demand. Seasonal products, minimum order quantities, price breaks and unreliable suppliers need adjustments.