Detailed guide
How to use the date and deadline calculator
Calculate a date forwards or backwards
Choose a base date, amount and unit. “Add” produces a later date, while “Subtract” looks backwards. Calendar days include every weekday. A week is seven days; months and years are shifted as calendar units rather than converted to a fixed number of days.
The business-day option skips Saturday and Sunday. Public holidays are not automatically excluded because legal deadlines can treat holidays differently according to jurisdiction, place and procedure. Regional planning tools are available when holiday subtraction is the main purpose.
Month-end and leap-year details
Months do not have equal lengths. Starting at the end of a long month can produce a date in the following month when the target month has no corresponding day. February 29 also deserves attention when shifting by complete years.
For recurring payments and contractual periods, check how the governing document handles a missing calendar date. Some agreements use the last day of the target month, while others rely on a fixed day count.
Deadline guidance, not legal advice
A legal deadline depends on more than an amount of time. The triggering day may be included or excluded, deemed service rules can alter the start, and an end date on a weekend or holiday may be extended. These rules vary by country and process.
The tool therefore provides a transparent mathematical date shift. Objection, termination, tax and court deadlines should be confirmed against the applicable law and, when needed, with qualified advice.