Move a date forward or back
Choose your starting date, whether to add or subtract, and one amount and unit. The result includes the weekday and the number of calendar days moved. Try an example uses January 31, 2024 plus one month: February 29, 2024, a Thursday.
How the calculation works
A week is seven days. Month and year moves go directly to the target month, then use its last valid day if needed. They do not repeat a one-month step. This follows the constrained calendar-arithmetic approach described in the Temporal calendar-date documentation.
Dates use Gregorian leap-year rules, even before that calendar was adopted locally. The range is January 1, year 0001 through December 31, year 9999. The amount must be a whole number from 0 to 3,652,058. The result must also stay within the supported date range, so large month or year moves may be rejected. No dates are saved or added to the page address.
For an age in years, months, and days, use the Age calculator. For a shift measured by the clock, use the Hours calculator.