Date Calculator
Add or subtract days, weeks, months, or years from any date. Includes end-of-month and leap-year edge cases.
Add or subtract from a date
Result date
Thursday, June 3, 2027
That is a Thursday, in 365 days.
Days from today
365
Weekend?
No
Timing
Future
ISO date
2027-06-03
Frequently Asked Questions about the Date Calculator
In what order are years, months, weeks, and days applied?
Years and months are applied first as calendar arithmetic, then weeks and days are added as fixed 7-day and 1-day units. This matches how humans say 'one month and three days later'.
What happens if I add a month to January 31?
The day is clamped to the last valid day of the target month. January 31 plus one month gives February 28 in a non-leap year, or February 29 in a leap year. The day never overflows into the next month.
Does this calculator handle leap years?
Yes. Adding one year to February 29 lands on February 28 in non-leap years and February 29 in leap years. Day counts across leap-year boundaries automatically include the extra February 29 when relevant.
Can I subtract time to find a past date?
Yes. Switch the operation to subtract and the calculator walks backward through the calendar using the same clamping and leap-year rules used for forward calculations.
Why does the result show a different weekday than I expected?
Calendar arithmetic does not preserve weekdays. Adding one month to a Monday rarely lands on another Monday. The calculator returns the exact weekday of the resulting date using your local calendar.