Reorder Forecast Calculator
Calculate days until reorder: (on hand + on order − reorder point) ÷ forecast daily demand.
In short
Formula: Days until reorder = (on hand + on order − reorder point) ÷ forecast daily demand.
What this calculator does
Calculate days until reorder: (on hand + on order − reorder point) ÷ forecast daily demand. Worked example, questions and limitations included.
Use it to turn Stock on hand, Stock on order (enter 0 if none), Reorder point, Forecast daily demand into a checked result you can compare, copy, or rerun with different assumptions.
The page shows the formula, a numeric worked example, and the assumptions that affect this supply chain calculation.
Inputs and what they mean
- Stock on hand
- — number value.
- Stock on order (enter 0 if none)
- — number value.
- Reorder point
- — number value.
- Forecast daily demand
- — number value.
How to use it
- Enter each value in the unit shown next to the box (use the unit converter first if your numbers are in other units).
- Check the breakdown to see every intermediate step.
- Read the limitations before relying on the result.
Formula
Uses inventory position against the order point (ASCM dictionary).
Reorder point comes from the reorder point calculator.
Demand is your forecast, assumed steady over the horizon.
Days until reorder = (on hand + on order − reorder point) ÷ forecast daily demand.
Inputs used: Stock on hand, Stock on order (enter 0 if none), Reorder point, Forecast daily demand.
Worked example
When to order
- 1,500 − 380 = 1,120.
- 1,120 ÷ 40 = 28 days.
Reading the result
The headline figure is the main answer. Any breakdown underneath shows the parts that make it up, so you can check the working and see what changes when you adjust an input.
Limitations and assumptions
- Steady demand.
- Ignores backorders.
- Continuous review.
- Results are planning estimates built only from the figures you enter. No prices, rates, demand patterns or service levels are built in, and the results are not supplier quotes or carrier rates.
- The result depends on the values you enter for this reorder forecast calculator; it does not supply missing rates, rules, prices, dates, or assumptions for you.
Common questions
Why include on-order stock?
Inventory position, not on-hand, is what reorder points are compared with. Check the formula, example, and limitations on this page before using the result for a real supply chain decision.
Demand will rise?
Use the higher forecast; the answer shortens. Check the formula, example, and limitations on this page before using the result for a real supply chain decision.
Result is zero?
You are at or below the reorder point — place the order. Check the formula, example, and limitations on this page before using the result for a real supply chain decision.
How do I use the Reorder Forecast Calculator?
Enter the required values for Stock on hand, Stock on order (enter 0 if none), Reorder point, Forecast daily demand. The calculator applies the formula on this page and shows the main result with any supporting breakdown so you can check the arithmetic.
What formula does the Reorder Forecast Calculator use?
Days until reorder = (on hand + on order − reorder point) ÷ forecast daily demand. The visible formula section above lists the calculation path and the edge cases the page handles, so the result can be checked without relying on the form alone.
Can the Reorder Forecast Calculator be used for exact decisions?
Use it as a calculation aid, not as a substitute for checking the underlying rule, contract, policy, or professional advice that applies to your situation. When a result depends on local rules, personal details, prices, or dates, enter those values yourself and confirm them before acting.
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