Date arithmetic

Add or subtract dates

Move a date by calendar units. Years are applied first, then months, then weeks and days; invalid month-end dates clamp to that month’s final day.

Result

Monday, April 8, 2069

Added to Saturday, March 9, 2069.

ISO date2069-04-08
WeekdayMonday
Absolute day distance30

Month-end clamping happens after years and again after months. For example, subtracting one month from March 31 lands on February 28 or 29.