Leihnummer

Leihnummer is a term used in German-speaking libraries, archives and museums to denote a unique identifier assigned to a loan transaction or to a lent item. It serves as a reference within the institution’s circulation or loan management system and helps staff and users retrieve the complete loan record.

In practice, a Leihnummer is linked to other identifiers such as the item’s bar code or Inventarnummer (inventory number) and the borrower’s account. A loan record typically includes the Leihnummer, item identifier, borrower ID, checkout date, due date, branch, and current status (active, renewed, returned, overdue). The Leihnummer enables tasks such as renewals, holds, fines calculation, and coordination of interlibrary loan processes.

Formats and standards for Leihnummer vary by library system. They are often numeric or alphanumeric and may incorporate a year or code to indicate a batch of loans. There is no universal standard governing Leihnummer formats; each institution defines its own scheme.

Beyond libraries, Leihnummer is also used for the lending of other materials or equipment within university or corporate settings, with similar purposes of tracking movement and status. The concept emphasizes transaction-level identification rather than item-level identification alone.

Privacy and data protection considerations apply, since loan records can reveal user borrowing behavior. Access to Leihnummer data is typically restricted to staff and governed by the institution’s data policies and retention schedules.