Kalendermonat

Kalendermonat, also calendar month, is a unit of time in German that refers to a month as defined by the civil calendar (the Gregorian calendar). It is the interval from the first day to the last day of a month, regardless of the number of days in that specific month. Therefore, Kalendermonate can have 28, 29, 30, or 31 days, with February having 28 days in common years and 29 days in leap years.

In practice, the term is used in legal, administrative and accounting contexts to express deadlines and durations that are tied to calendar months rather than to a fixed number of days. For example, a contract might require a notice period of two Kalendermonate, or a payment term of one Kalendermonat after receipt of an invoice. The use of Kalendermonat helps ensure that the period ends on a predictable calendar date (typically the end of a month), independent of weekends or holidays.

Difference from other concepts: A Kalendermonat is not identical to a fixed number of days and is distinct from a “Wirtschaftsmonat” or “Geschäftsmonat,” which may be defined differently in contracts or business practice. It is also distinct from "Kalendertage" (calendar days), which count every day.