Hi,
Please refer to this forum answer. It gives a detailed explanation of the difference between onhand quantity and forecasted quantity.
https://www.odoo.com/forum/help-1/odoo-10-qty-on-hand-and-forecast-quantity-diffeence-124057

Reply: In Odoo, the "Forecasted Quantity" and "On Hand Quantity" are two different concepts that represent different aspects of inventory management:

Forecasted Quantity:
The Forecasted Quantity in Odoo represents the estimated or projected quantity of a product that is expected to be available in the future based on various factors such as sales orders, purchase orders, manufacturing orders, stock moves, and demand forecasts. It helps in planning and predicting future stock availability.

The Forecasted Quantity is primarily used for planning purposes, allowing businesses to anticipate future inventory needs, make procurement decisions, and optimize stock levels.

On Hand Quantity:
The On Hand Quantity in Odoo represents the actual physical quantity of a product that is currently available in stock at a specific point in time. It reflects the real-time inventory level for a particular product in a specific location.

The On Hand Quantity provides an accurate representation of the available stock at any given moment, helping businesses manage inventory, fulfill customer orders, and avoid stockouts or overstock situations.

Regards,

Ksolves Team!