Time Calculators
Age, dates, durations, countdowns, business days, fiscal periods.
A professional Time & Date suite — age, exact age, birthdays, countdowns, date & time differences, durations, business & working days, days/weeks/months/years between dates, leap year, day-of-week, ISO calendar week, and fiscal date. Deterministic offline calendar math with copy, print, and multi-format export.
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Most used in Time.
Age Calculator
Your exact age in years, months, and days.
Exact Age Calculator
Total lived time down to seconds.
Birthday Calculator
Upcoming birthdays and their weekdays.
Birthday Countdown Calculator
Days remaining to your next birthday.
Date Difference Calculator
Difference between two calendar dates.
Time Difference Calculator
Elapsed time between two clock times.
Duration Calculator
Add or subtract durations (HH:MM:SS).
Countdown Calculator
Time remaining to any target date/time.
New
Recently added.
Fiscal Date Calculator
Fiscal year and quarter (configurable FY start).
Calendar Week Calculator
ISO 8601 week number for any date.
Day of the Week Calculator
Weekday for any date.
Leap Year Calculator
Check whether any year is a leap year.
Years Between Dates
Years, months, and days between two dates.
Months Between Dates
Whole months + leftover days.
Weeks Between Dates
Weeks + leftover days between two dates.
Days Between Dates
Whole days between two dates.
All Time Calculators
20 tools available.
Age Calculator
Your exact age in years, months, and days.
Business Days Calculator
Business days between two dates.
Countdown Calculator
Time remaining to any target date/time.
Date Difference Calculator
Difference between two calendar dates.
Working Days Calculator
Add N working days to a start date.
Birthday Calculator
Upcoming birthdays and their weekdays.
Birthday Countdown Calculator
Days remaining to your next birthday.
Day of the Week Calculator
Weekday for any date.
Days Between Dates
Whole days between two dates.
Duration Calculator
Add or subtract durations (HH:MM:SS).
Exact Age Calculator
Total lived time down to seconds.
Leap Year Calculator
Check whether any year is a leap year.
FAQ
About Time Calculators.
How accurate are the date calculators?
Every calculator uses proleptic Gregorian rules: leap year (÷4, except ÷100 unless ÷400), correct month lengths, and ISO 8601 week numbering. Nothing is rounded to the nearest month; borrowing days from the previous month is exact.
Do the tools handle time zones?
Date-only calculators are timezone-neutral — they compute on local calendar dates. Countdown and timer tools use your browser's local clock. Cross-timezone conversion is intentionally out of scope for this suite to avoid ambiguity.
Can I customize weekends and holidays?
Yes — Business & Working Day calculators accept a weekend preset (Sat+Sun, Fri+Sat, Sun-only, or none) and a free-form list of holiday dates in YYYY-MM-DD format.
Does the Age Calculator match how humans count age?
Yes. It borrows days from the previous month when needed, so a person born on Feb 29 ages exactly one year on Feb 28 in non-leap years and on Feb 29 in leap years.
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