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, October 10, 1987

Added to Thursday, September 10, 1987.

ISO date1987-10-10

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.