MinusDays

MinusDays is a common method in date and time libraries that returns a new date or datetime by subtracting a specified number of days from an existing value. It operates on calendar days and typically does not mutate the original object, supporting immutable usage patterns.

In Java, the java.time package provides methods such as LocalDate.minusDays(long daysToSubtract), LocalDateTime.minusDays(long daysToSubtract), and ZonedDateTime.minusDays(long daysToSubtract). Each returns an instance of the same type with the date reduced by the given number of days. For example, LocalDate date = LocalDate.of(2023, 3, 15); LocalDate earlier = date.minusDays(10);

Behavior notes: minusDays uses calendar arithmetic, so subtracting across month or year boundaries yields the expected date. When used with time-zone aware types like ZonedDateTime, the operation changes the date while preserving the time component and zone, and it may interact with daylight-saving rules in edge cases.

Other ecosystems also provide similar functionality. In Kotlin’s kotlinx-datetime, LocalDate.minusDays exists; Joda-Time’s DateTime.minusDays is available in older environments. In JavaScript ecosystems, similar operations appear under names such as subDays (date-fns), or subtract (Moment.js, Day.js).

See also: plusDays, minus, ChronoUnit.DAYS.