Days between dates, countdowns, business days excluding holidays, age and anniversaries.
- 11date calculators
- 2015–2035holiday table
- 3,200+answers checked in tests
Try it here
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Each square is one day, and holidays come from Daycount’s US federal holiday table for 2015–2035.
Today is already filled in, so changing the end date alone gives you the count
- Pick a calculator‘Between dates’ is open when the page loads, and tapping a name such as ‘Countdown’, ‘Business days’ or ‘Age’ switches to it.
- Type dates as digitsDate boxes take digits like 03152004 or 03/15/2004, and ‘Between dates’ shows the days plus the same span in weeks, months and hours.
- Decide on the first dayTurn on ‘Include start date (count the first day too)’ and Oct 1 to Oct 3 counts as 3 days instead of 2.
- Choose the holiday calendarThe holiday menu at the top starts on ‘US holidays’ and can switch to ‘Korean holidays’, and business-day results list each skipped holiday with its date and name.
It can also
What it checks and discloses
It is tested automatically against more than 3,200 answers worked out separately with Python’s date library.
Every release is checked against 3,200+ answers worked out separately in Python
Rules and sources
- Days between dates
- The later date minus the earlier one, plus one day with ‘Include start date’ on.About Daycount
- Adding months
- Counted date to date, using the month’s last day when it is too short, so January 31 plus one month is February 28 (29 in a leap year).About Daycount
- Business days
- Saturdays, Sundays and the selected calendar’s holidays are skipped, on the days they are observed.About Daycount
- US holidays
- The 11 federal holidays in 5 U.S.C. 6103, skipped on the day federal offices observe them: the Friday before a Saturday holiday, the Monday after a Sunday one.U.S. Office of Personnel Management: Federal Holidays
- South Korea: public holidays
- 2015 to 2035 come from the open-source holidays library (0.83), plus Labor Day (May 1) and Constitution Day (July 17), public holidays from 2026, with their substitute days under the regulation.holidays, an open-source library · Regulations on Holidays of Government Offices (Korean, National Law Information Center) · Checked Oct 30, 2026
- Age
- Whole years since the last birthday, then months and days; people born on February 29 have their birthday on March 1 in other years.About Daycount
One-off days off announced later, such as those given by executive order, aren’t included.
6 guides
- How to count the days between two dates (and when to add 1)
- How to count business days and find a deadline
- US federal holidays on a weekend: which day is observed
- Adding months to a date: what happens to January 31
- How to calculate your exact age in years, months and days
- ISO week numbers: why January 1 can be in week 53
Added Korea’s 2026 holiday changes and made every date box take typed digits
Labor Day (May 1) and Constitution Day (July 17), public holidays in South Korea from 2026, are now in the Korean holiday list and business-day counts; in 2027 both fall on a Saturday, so May 3 and July 19 are days off instead.
Every date box now takes typed digits first, with the calendar on a button to its right.
On a countdown date, a birthday or an anniversary, confetti flies, and a holiday result gets a ‘Holiday’ stamp.
The 11 calculators were sorted into four groups: ‘Spans & countdowns’, ‘Move a date’, ‘Age & anniversaries’ and ‘Calendar’.
People born on February 29 now have their birthday on March 1 in other years.
The English edition, Daycount, opened with 6 guides of its own.
Daycount first went live in Korean, with 6 Korean guides.
