Free Date & Time Tools
14 free calculators for dates, ages, working days, countdowns, time zones and world calendars. Everything runs in your browser — nothing you enter is sent anywhere.
Date calculators
Add to dates, measure the gap between them, count working days and work out ages.
Date Calculator
Add or subtract days, weeks, months or years from any date.
Date Difference
Find the exact time between two dates in years, months, weeks and days.
Business Days Calculator
Count working days between dates, or add working days — skipping weekends and a country's public holidays.
Age Calculator
Work out exact age in years, months and days — and the countdown to the next birthday.
Countdowns
Count the days to — or since — any date, or run a live countdown clock.
Calendar lookups
Weekdays, week numbers, day numbers, leap years and repeating calendars.
Day of the Week
Find which day of the week any date falls on.
Week Number
Find the ISO week number for any date — or the dates of any week.
Day of the Year
Find the day number of any date (1–366), or which date a day number falls on.
Leap Year Checker
Check whether any year is a leap year, and find the next and previous leap years.
Calendar Repeat Finder
Find the years whose calendar matches a given year exactly.
Time zones & calendar systems
Convert times between countries and dates between the world's calendars.
Frequently asked questions
Are these date tools free?
Yes. Every tool is free to use with no sign-up, and there are no limits on how often you use them.
Is anything I enter sent to a server?
No. All calculations run in your browser, so the dates, birthdays and times you enter never leave your device.
Do the tools handle leap years and time zones?
Yes. Date maths follows the Gregorian calendar with its leap-year rules, and the time zone tools use your browser's time zone database, including daylight saving changes.
Which countries' holidays does the business days calculator know?
All 62 countries on this site, using the public holidays listed on each country page for 2026–2027.