How it works
Find the date a set number of days, weeks, months or years before or after a starting date. It is useful for deadlines, due dates, notice periods, warranty expirations and follow-up appointments.
Adding days and weeks counts actual calendar days. Adding months or years keeps the same day of the month; when that day does not exist (such as January 31 plus one month), the result moves back to the last day of the target month.
Questions people ask
What is January 31 plus one month?
February 28, or February 29 in a leap year. The calculator uses the last valid day of the month rather than rolling over into March.
Does this count business days only?
No, it counts every calendar day. Use the business days calculator to skip weekends and holidays.
Is adding 12 months the same as adding 365 days?
Not always. Adding 12 months lands on the same date next year, which is 366 days later when a February 29 falls in between.