Quick Summary: The Cover Forward Period represents the full forecasting horizon used to convert Safety Stock (SS), Lead Time (LT), and Replenishment Cycle (RC) from days into units. It ensures that the Recommended Order Quantity (ROQ) is based on the correct future demand windows rather than a single average forecast.
Why the App Uses Days Instead of Units
Safety Stock, Lead Time, and Replenishment Cycle are expressed in days because days can be converted to units dynamically.
This allows order sizing to adjust automatically when demand changes.
A 30 day Replenishment Cycle results in more units during high demand periods
The same 30 days results in fewer units when demand is lower
Days automatically scale to the demand pattern. Units do not.
Formula:
Units = Days × Daily forecast
Daily forecast = Units ÷ Days
This ensures the system always responds to future demand, not a fixed unit value set in the past.
How Days are Converted to Units
The app translates the days from your policy into the number of units you need to order by using the forecast.
Importantly, each segment of the cover forward period is calculated separately, using the forecast from its specific future time window:
Lead Time Units: The system uses the forecast between Now → LT to convert lead time days into units.
Safety Stock Units: It then uses the forecast between LT → SS to convert safety stock days into units.
Replenishment Cycle Units: Finally, it uses the forecast between SS → RC to convert replenishment cycle days into units.
These three unit quantities are added together to create the Order Up To Level, which ultimately determines the size of your recommended order.
The Projection Tab
If you need to see the exact forecast values used in each part of the Cover Forward Period, you can do so directly on the Projection tab.
Navigate to Inquiry screen > Projection tab
➜ For more on this topic, read: Projection Tab Explained
Why the Order Matters
The calculation follows a specific sequence: Lead Time, then Safety Stock, then Replenishment Cycle, because it mirrors how inventory risk unfolds in real operations and ensures continuous protection from today through the next planned ordering opportunity.
Lead Time (LT) - Covers the waiting period.
Once you place an order, the supplier needs time to deliver. During this period, stock is consumed according to the immediate forecast.Safety Stock (SS) - Buffers variability during the wait.
If the order is delayed or demand is stronger than expected, the item falls into the Safety Stock range. This portion uses the forecast after the Lead Time period.Replenishment Cycle (RC) - Extends coverage to the next order point.
Once the delivery arrives, stock should last through the planned Replenishment Cycle. This portion uses the forecast after Safety Stock.
In practice, this allows the ROQ to match the real profile of demand rather than assuming all days are equal.
⚠️ Watchouts
Lead time accuracy: Incorrect Lead Time values distort all unit conversions.
Forecast variability: LT, SS, and RC use different parts of the forecast, so expect different daily forecast values.
Input changes: Adjusting SS, LT, or RC immediately changes the Cover Forward Period and the ROQ.
💡 Tips
Use the Projection tab: Expand the table to see the exact forecast slices used in each part of the calculation.
Link to ROQ logic: For how Cover Forward converts into the final order quantity, see The Recommended Order Quantity (ROQ) Calculation Explained
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