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Date & Time Calculators

Age, date difference, timesheets, countdowns, and time zone calculators.

Date and time calculations appear everywhere — project deadlines, age milestones, payroll hours, travel across time zones, and countdowns to important events. Our date & time calculators handle calendar math, business day counts, duration formatting, and timezone conversions in seconds.

Stop counting days on your fingers or wrestling with spreadsheet formulas. Enter two dates to find the difference, add or subtract intervals, convert Unix timestamps, or calculate exact age down to the day.

HR teams, project managers, travelers, parents, and event planners all rely on accurate date math. Every tool below is free, instant, and works on mobile and desktop.

Age & milestones

Exact age from date of birth, age in total days, and countdown timers to future events.

Date arithmetic

Days between dates, add/subtract days or months, week numbers, quarters, and leap year checks.

Work & payroll

Working days between dates (excluding weekends), time card totals, and hours/minutes calculators.

Time zones & formats

Convert between time zones, military (24-hour) time, Unix timestamps, and world clock views.

All Date & Time Tools

17 free calculators — click any tool to open it instantly.

Age Calculator

Calculate exact age in years, months, days, hours, and minutes — from birth to today or any custom target date.

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Date Difference

Calculate the exact number of days, weeks, months, and years between any two dates.

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Working Days Calculator

Count the number of business (working) days between two dates, excluding weekends.

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Time Zone Converter

Convert a time from one time zone to any other time zone around the world.

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Days Until Calculator

Find out exactly how many days, hours, and minutes until any future date or event.

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Unix Timestamp Converter

Convert Unix timestamps to human-readable dates and vice versa. Supports seconds and milliseconds.

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Week Number Calculator

Find the ISO week number for any date, or determine which date a given week number starts on.

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Date Add/Subtract

Add or subtract days, weeks, months, or years from any date to find a past or future date.

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Time Duration Calculator

Calculate the duration between two times, or add/subtract hours, minutes, and seconds to a given time.

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Hours Calculator

Add and subtract hours and minutes for timesheets, payroll, and project time tracking.

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Military Time Converter

Convert between 12-hour (AM/PM) and 24-hour (military) time formats instantly.

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Leap Year Calculator

Check if any year is a leap year and find the next or previous leap years from any date.

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Time Card Calculator

Calculate total work hours, overtime, and pay from clock-in/clock-out times for weekly timesheets.

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Countdown Timer

Set a countdown timer for any duration — minutes, hours, or days — with alerts when time is up.

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World Clock

View the current time in multiple cities and time zones around the world simultaneously.

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Age in Days Calculator

Find your exact age in total days, hours, minutes, and seconds since birth — updated in real time.

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Quarter Calculator

Find which fiscal or calendar quarter a date falls in, and get quarter start/end dates for any year.

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Popular Topics in Date & Time

age calculatordays between datesworking daystime zone converterUnix timestampcountdowndate add subtracthours calculatorweek numbermilitary time

Frequently Asked Questions

Do working day calculators exclude holidays?
Our working days calculator excludes weekends (Saturday and Sunday) by default. Public holidays vary by country and region — for holiday-aware counts, manually adjust or note holidays in your planning.
How is age calculated?
Age is computed from your birth date to today (or a date you specify), accounting for whether the birthday has occurred yet in the current year. Leap years and month-length differences are handled automatically.
What about daylight saving time?
Time zone conversions use standard UTC offsets. DST transitions may affect specific dates — double-check results around spring forward / fall back weekends for critical scheduling.
Can I calculate days until a wedding or deadline?
Yes. Use the Days Until calculator or Date Difference tool. Both show the exact number of days, weeks, and months remaining.