7 subcategories · 35 calculators
Dates & Time
The Dates & Time section covers the full range of calendar and clock questions that come up in everyday life — from calculating an exact age in years, months, and days, to counting down to a future date, working out how many business days remain before a deadline, or finding what date falls a set number of weeks from now. Calendar arithmetic is deceptively tricky: months have different lengths, leap years shift February, and weekends and public holidays affect working-day counts. These tools handle all of that automatically.
Subcategories
Age & Birthdays
Exact age, birthday countdown, and age difference calculators.
Date Calculations
Date difference, add/subtract days, and days-until calculators.
Business Calendars
Business-day, working-day, and weekday counting calculators.
Time Calculations
Clock-time addition, subtraction, countdown timers, and elapsed-time calculators.
Time & Hours
Work hours, timesheet, time zone, and time duration calculators.
Calendar Reference
Day-of-week, leap year, days-in-month, and calendar reference calculators.
Religious Holidays
Calculate dates for Christian, Jewish, Islamic, Hindu, and Buddhist observances.
Popular tools
Dates & Time / Calendar Reference
Easter Date Calculator
Use this Easter date calculator to find when Easter Sunday falls, compare Western and Orthodox Easter, review Holy Week dates, and scan nearby years.
Dates & Time / Age & Birthdays
Age Calculator
Use this age calculator to find exact age in years, months, and days, count down to the next birthday, compare age difference between two birthdays.
Dates & Time / Calendar Reference
Age on Other Planets Calculator
Convert an Earth age or birthdate into Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune years, with orbital periods.
Dates & Time / Time Calculations
Alarm Clock
Set an online alarm clock with sound, live countdown, labels, quick presets, and snooze for same-session browser reminders.
Dates & Time / Religious Holidays
Buddhist Holiday Calculator
Use this Buddhist holiday calculator to estimate Vesak, Losar, Bodhi Day, Makha Bucha, Asalha Puja, Buddhist Era context.
Dates & Time / Business Calendars
Business Days Calculator
Count business days between dates, compare inclusive and exclusive rules side by side, choose a working-week pattern, subtract manual holiday totals.
Common questions
Dates & Time questions.
What is the difference between the age calculator and the date difference calculator?
The age calculator is specifically designed for birthdays: it measures elapsed years, months, and days from a date of birth to today (or any reference date) and shows the countdown to the next birthday. The date difference calculator is more general: it measures the gap between any two arbitrary dates and shows the span in multiple units including years, months, weeks, days, and business days. Use the age calculator for birthdays; use the date difference calculator for any other two dates.
When should I use business days instead of calendar days?
Use business days (weekdays only) whenever a deadline depends on working-day counting — for example, contract notice periods, payment terms, shipping windows, or legal filing deadlines. Use calendar days when every day in the range counts regardless of the day of the week, such as for a holiday countdown or a personal milestone.
How does the calculator handle February 29 leap-year birthdays?
In non-leap years, people born on February 29 are considered to have their birthday on either February 28 or March 1 depending on local convention and personal preference. The birthday calculator and age calculator both note the leap-year edge case and apply the most common convention: February 28 in the birth year's non-leap equivalent.