Stock, shipping and production
Inventory Reorder Point Calculator
Plan when to replenish one stock item, accounting for expected demand, incoming stock, backorders and supplier pack sizes.
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How to use this tool
1. Enter your own figures below, or choose Load example to try the worked example. Check the units beside each field.
2. Select Calculate to see the result and its breakdown. If you change an input, calculate again before copying or printing.
3. Use Copy summary or Print / save PDF to keep your assumptions and results together. Reset clears the form.
How the calculation works
Reorder point = average daily demand × lead time + safety stock, rounded up to whole units. Inventory position = usable stock + confirmed incoming stock − backorders. At or below the trigger, target position covers lead time plus your additional days and safety stock. The order fills the gap to that target and rounds up to a supplier multiple. Above the trigger, suggested order is zero.
Worked example
Demand of 10 units/day, 7-day lead time and 30 units of safety stock give a 100-unit reorder point. With 60 on hand, 20 incoming and 10 backordered, position is 70. Seven extra cover days give a 170-unit target. The 100-unit gap rounds to an order of 108 units in packs of 12.
Questions and assumptions
What this estimate includes
Safety stock is an input, not a calculated service-level guarantee. Demand spikes, seasonality, expiry, storage capacity, cash limits and missed deliveries are excluded. Incoming stock must be genuinely available in the planning window. Negative inventory position is permitted when backorders exceed available and incoming stock.
Can I save or share my result?
Copy summary includes the current inputs and results. Print / save PDF creates a local report with the calculation scope and source links. Your figures are not added to the page URL or stored by this tool. Refreshing clears the form.
Sources and further reading
Built and maintained by Custom Logic. Page updated .