Time and Date - Add, Subtract

Calculator for adding or subtracting days, hours, minutes or seconds to a certain time and date. Enter date and time, as well as the time that should be added or subtracted. Choose the according arithmetic operator. The new date and time will be calculated. The different lengths of the months as well as leap years are taken into account. Current date and time (CET) are preset.

Example: if it is 13 o'clock noon now, then one day and 14 hours ago it was 23 o'clock two days previous (- days: 1 hours: 14).

Another example: if you add 150 days to the thirteenth of September, you get the first of April of the following year if this is not a leap year, and the thirty-first of March if the following year is a leap year. Because the 29th of February of the leap year makes it one day longer.

The date is determined by the number of the day in the month, the number of the month and the number of the year. The day is a number from 1 to 31, the month is a number from 1 to 12 and the year that this calculator can work with begins with the year 100. Years before and before our era cannot be processed here. The Julian calendar before the 16th century is also ignored here. This calculator is intended for everyday applications; there are other tools for special historical cases.
The time is of course given in hours, minutes and seconds. Days, hours, minutes and seconds can be added or subtracted. Calculating with months or years is not possible because they do not have a specific length; months have 28 to 31 days, years have 365 or 366 days.