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Today’s video is a tutorial on how to set Safety Stock Days in Prophet 21. Safety Stock Days can affect your calculations for things like ‘Up To’ when using P21 for your Purchasing.

Safety Stock for an item is on a per-location basis.  This means you can have a different setting for each location in Prophet 21. Safety Stock also only applies to items set up as Up To or EOQ.  It does not apply to Min/Max or Order Point/Order Quantity fixed replenishment methods.  In this process, Prophet 21 will ignore any items with a safety stock setting that are not EOQ or Up To.

You can access Safety Stock within several different screens in Prophet 21.

    • In ABC Class Maintenance

    • In Supplier Maintenance

    • In PO Requirements/Generation (PORG)

    • In Item Maintenance

Item Maintenance is one of the most common places to set up Safety Stock and is where we will work today. 

How to Set Safety Stock Days:

Start by opening the item in Item Maintenance.

The Safety Stock is located within the Replenishment tab.

You can set Safety Stock in terms of four different measurements:

    • By ABC Class

    • Days

    • Deviation Multiplier

    • Service Level (which must be turned on in system settings)

This tutorial focuses on Days as it is the easiest way to demonstrate how to use the function.

To be clear, when you set safety stock as a fixed number of days (either on the item or the ABC class), you are choosing a number of days of usage.  The usage is based on the average period usage. 

For our purposes, we will work straight on the item level.

    • Set your Safety Stock Days.

    • Hit Save.

This will immediately affect your calculation.


    • Start with an initial Calculated Order Point of 105 days. This number populates down through the system’s formula.

    • Add 30 Days.

    • Return to the Criteria tab and refresh that data.

    • When you reopen the Purchase Stock Card, the initial time of 105 days will be replaced with 159 days.

Basically, by utilizing Safety Stock, you add additional days’ worth of inventory which prompts you to order more units than initially required.

Remember: Safety Stock Days can be manipulated in several different ways. Choose your preferred method based on whatever practice fits your business best.

If you guys have any questions on setting Safety Stock or you want to see some videos with some other topics, put a comment down below.

Continue Learning: Using ‘Up To’ in Inventory Management explained.