How to use the date calculator
- Choose a tab: D-day, Days between, Add / subtract or Age.
- Pick the dates. The Today button fills in today’s date.
- The result updates instantly — no button to press.
Frequently asked questions
Does “days between” count both dates?
By default it counts the nights between them, like most calculators. Tick “Include the end date” to count both the first and last day.
What happens when I add a month to January 31?
Months have different lengths, so the result moves to the last day of the shorter month — February 28, or 29 in a leap year.
Are holidays excluded from weekdays?
Weekdays count Monday to Friday only. Public holidays differ by country and are not removed.
Which time zone is “today”?
Today is taken from your device’s own clock and time zone.