A written tally of all of a taxpayer's personal property. This inventory will also denote how much was paid for each item and when, along with each item's current market value. Property inventories are generally used by taxpayers to calculate gain or loss on sale of property, as well as to report losses of property to insurance companies. Every taxpayer would be wise to keep a property inventory in order to facilitate tax and insurance reporting. This inventory should be updated periodically and kept in a safe place, such as a bank deposit box. Keeping an online inventory is also a convenient way to track one's property inventory.