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

Saturday, March 29, 1975

Added to Thursday, February 27, 1975.

ISO date1975-03-29

WeekdaySaturday

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.