Kalenderdatum

Kalenderdatum is the date of a specific day on the civil calendar, defined by year, month and day. It does not include time of day or time zone, and is used to label events, deadlines, and records in everyday life, administration, and computing.

In computing and data exchange, a kalenderdatum is typically stored as a date value. The standard textual representation is ISO 8601: YYYY-MM-DD, for example 2025-12-08. Many locales also display the same date as DD.MM.YYYY or MM/DD/YYYY. When time information is needed, a separate time component or a timestamp is used, which combines the kalenderdatum with hours, minutes and seconds and may include a time zone.

Key properties include that the kalenderdatum adheres to the calendar system in use, including leap years. For example, 2020-02-29 is a valid kalenderdatum, while 2019-02-29 is not. Calendar dates are used to plan, record, and communicate when events occur, when obligations are due, or when systems should become effective.

Kalenderdatum is distinct from related temporal concepts such as ordinal dates (the day’s number within the year) and Julian day numbers, which count days from a fixed epoch. It is also separate from time-specific concepts like timestamps or datetimes, which add time components to the date.