Difference between "On-hand" and "available quantity"
1. "On-hand quantity" The total number of stock-keeping units (SKUs) that are physically located in the warehouse location at the current time. This includes items that are already allocated to fulfilling production needs or sales orders.
"Available quantity" The total number of stock-keeping units (SKUs) that are currently available for use in filling a new order internally or externally for purposes such as production or distribution.
<< i.e. "Availability = On-hand Qty - Reservations - Pending transactions" >>
2. The "on-hand balance" is the quantity of 'active inventory' stored at a specific warehouse. 'Active inventory' is defined as the usable amount of an item that is in the warehouse. Inventory is 'active' if it is not 'damaged', 'expired' or 'being inspected'. The "on-hand balance" includes inventory that has been 'allocated', or 'set aside', for an order but has not yet been shipped.
The "available quantity" is the quantity of an item that is available to be allocated to orders. This quantity is the difference between the 'on-hand' and the 'allocated quantities'. The 'allocated quantity' is the quantity of an item that has been designated to customer orders at a specific warehouse, but has not yet been gathered and shipped.
The above 2 points will help you understand about "On-hand" and "Available quantity" in Quick Books.