Age and Birthday Calculator
Calculate an exact age, total days alive and the time remaining until the next birthday from a date of birth.
Date & time toolsOpenDate & time tools
Date and time calculators
Calculate ages, date differences, working time, countdowns, time zones and recurring schedules.
20 focused tools
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Date Difference Calculator
Calculate the calendar difference between two dates in years, months, weeks, days, hours and minutes.
Date & time toolsOpenAdd or Subtract Date Calculator
Add or subtract days, weeks, months or years from a chosen date and see the resulting calendar date instantly.
Date & time toolsOpenBusiness Days Calculator
Count weekdays between two dates and optionally exclude weekends or supplied holiday dates from the total.
Date & time toolsOpenDate Countdown Calculator
Calculate the days, hours, minutes and seconds remaining until a selected future date and time.
Date & time toolsOpenDay of the Week Calculator
Enter any valid calendar date to identify the weekday it falls on and review the formatted date.
Date & time toolsOpenWeek Number Calculator
Find the ISO week number and ISO week-year for any selected calendar date.
Date & time toolsOpenLeap Year Checker
Check whether a supplied year is a leap year using the Gregorian leap-year rules.
Date & time toolsOpenTime Duration Calculator
Calculate the duration between two clock times, including shifts that continue past midnight.
Date & time toolsOpenTime Addition and Subtraction Calculator
Calculate time using starting time, operation, hours, and minutes, then review the result and supporting breakdown.
Date & time toolsOpenWorld Clock
Show the current local time, date and UTC offset for up to four selected time zones in one live world-clock view.
Date & time toolsOpenTime Zone Converter
Convert a date and time from one selected time zone to another and review the corresponding local time.
Date & time toolsOpenMeeting Time Planner
Compare two time zones on a chosen date and find whole-hour meeting slots that fall inside the working-day window in both locations.
Date & time toolsOpenUnix Timestamp Converter
Convert between a calendar date and Unix timestamp in either direction.
Date & time toolsOpenHours Worked Calculator
Calculate hours worked using start time, end time, and unpaid break (minutes), with a supporting breakdown of the entered values.
Date & time toolsOpenTimesheet Calculator
Total worked time from timesheet entries while accounting for the breaks entered for each shift.
Date & time toolsOpenShift Planner
Generate a repeating shift schedule from a first shift date, days on, days off and number of cycles.
Date & time toolsOpenOvertime Hours Calculator
Calculate overtime using total hours worked, regular-hours threshold, overtime multiplier, and hourly rate, then review the result and supporting breakdown.
Date & time toolsOpenSleep and Wake-Up Calculator
Calculate sleep times using calculate from, time, sleep cycles, and time to fall asleep (minutes), then review the result and supporting breakdown.
Date & time toolsOpenRecurring Date Generator
Generate a reusable sequence of weekly, monthly or yearly dates from a selected starting date.
Date & time toolsOpenWhat this category covers
Date and time tools compare calendar dates, add intervals and count working days. They are useful for planning deadlines, durations, ages and schedules where month length and weekends matter.
Recommended starting tools
- Date Difference Calculator — Calculate the calendar difference between two dates in years, months, weeks, days, hours and minutes.
- Business Days Calculator — Count weekdays between two dates and optionally exclude weekends or supplied holiday dates from the total.
- Age and Birthday Calculator — Calculate an exact age, total days alive and the time remaining until the next birthday from a date of birth.
How to choose
Use a calendar-aware tool for months and years, and a duration converter only when fixed units are appropriate. Confirm timezone and holiday assumptions for business use.
Frequently asked questions
Are months treated as the same length?
Calendar calculations use real month boundaries; a simple duration conversion cannot do that.
Are public holidays included?
Only when the tool provides and uses a holiday input. Weekends and holidays are separate rules.