Zoho Inventory provides two methods of stock tracking:
- Accounting Stock: This represents the stock level in your books upon recording a transaction. The accounting stock of an item, increases whenever you record Bills and decreases when you create Invoices.
- Physical Stock: This indicates the stock level in your inventory when you physically move the stock from/to your warehouse. The physical stock of an item increases when you record Purchase receives and decreases when you create Shipments.
- You can view the quantity available in both modes of stock tracking on the item details page for better comparison of the stock level.
For example, lets say that that you have entered an opening stock of 20 pieces of an item. When you raise an invoice for 5 pieces, then you will notice that the Accounting Stock value reduces to 15 pieces but the Physical Stock remains as 20 pieces. This indicates that you have invoiced 5 pieces of this item but yet to get it shipped. Once you create a shipment for the invoiced quantity, the Physical Stock and Accounting Stock values would even out. Likewise, for purchase receives and bills.
The available quantity in each of the stock tracking method is further split into three categories:
Accounting Stock
Physical Stock

If the accounting stock and the physical stock are different, there is an error and an entry for losses must be made.
Shipments: Everything that comes out of the physical stock.
If the accounting and physical stock are different, you can correct it: Inventory - Inventory adjustments - New - Save.