Definition of 'Periodic Inventory'
A method of inventory valuation for financial reporting purposes where a physical count of the inventory is performed at specific intervals. This accounting method for inventory valuation only keeps track of the inventory at the beginning of a period, the purchases made and the sales during the same period and is recorded under the asset section of the balance sheet.
Investopedia explains 'Periodic Inventory'
With this valuation method, it is much harder to track which individual items were destroyed or stolen, but a cross-reference can be made with the sales revenue to get a rough estimate of what was sold versus what was not. Many see this method as being inferior to the perpetual inventory method, which keeps track of inventory at the point of sale.
This system is typically used by small businesses that can't afford or don't need an electronic tracking system (i.e. the bar code system).