Add days to a date or switch the operation to subtract them. Weeks, months, and years are also available when the offset spans a longer calendar period.
Calendar months are not approximated as a fixed number of days. When the target month is shorter, the result uses that month's final valid day before applying weeks and days.
Years and months are applied before weeks and days. When the destination month is shorter, the day is clamped to the final valid day of that month. For example, adding one month to January 31 produces the last day of February.
Date difference reports both a calendar duration and exact elapsed days. Business day mode treats Monday through Friday as working days, supports inclusive or exclusive boundaries, and removes valid custom holiday dates that fall on weekdays.
All dates are calculated as calendar dates in UTC, which prevents daylight-saving clock changes from creating 23-hour or 25-hour day differences.
Related date calculations: Date Calculator · Days Between Dates · Add Days to Date · Business Days