How it works
A reorder point is expected demand during supplier lead time plus a safety stock allowance. It identifies a stock level rather than an order quantity.
The formula
Keep currency, units and time periods consistent. Percentage inputs use percentage points (enter 5 for 5%). Results are rounded only for display; tiny nonzero values may use scientific notation. Undefined ratios are shown as unavailable.
Average daily sales: 12 units; Lead time: 15 days; Safety stock: 60 units; Demand during lead time: 180 units; Reorder point: 240 units; Inventory on hand: 420 units; Units above ROP: 180 units; Estimated days until reorder: 15 days.
Calculation method
Daily demand can be entered directly or calculated from units sold during an observed period. Buffer days translate into safety stock at that average demand.
Interpretation
Inventory coverage measures how long stock lasts; days until reorder measures how long before reaching the reorder threshold. These are different planning questions.
Limitations
Inbound stock is excluded unless explicitly included. Delivery uncertainty, seasonality, backorders and variable demand are not modeled; zero demand does not establish a reorder date.
Method and reference sources
Method and content checked 2026-09-20. These sources provide background, not endorsement or professional certification. The formula and limitations above define this calculator.
- SBA — Break-even pointContribution, variable costs and fixed-cost break-even context; tool-specific extensions are explained above.
Frequently asked questions
Should inbound stock reduce the reorder requirement?
Include inbound stock only if it will be usable in time for the demand period. The tool lets you exclude it; it does not verify arrival dates or supplier reliability.
What is a worked example for Inventory Reorder Point?
Average daily sales: 12 units; Lead time: 15 days; Safety stock: 60 units; Demand during lead time: 180 units; Reorder point: 240 units; Inventory on hand: 420 units; Units above ROP: 180 units; Estimated days until reorder: 15 days.