◷ Date & time calculator category

Date & Time Calculators

Explore 12 free online calculators for ages, dates, durations, workdays, time zones, countdowns and schedules. Choose a calculator below to open the completed tool.

Showing all 12 date and time calculators.
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Date & TimeDates · Durations · SchedulingFree Online Tools

Date & Time Calculator Tools

Age Calculator

Calculate age between a birth date and a selected date in years, months and days, with total days and next-birthday details.

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Date Difference Calculator

Measure the difference between two calendar dates as years, months and days plus total days, weeks and counting options.

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Add or Subtract Date Calculator

Add or subtract years, months, weeks and days from a selected calendar date with month-end clamping and a transparent calculation summary.

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Time Duration Calculator

Calculate elapsed clock time between start and end times with optional overnight handling, decimal hours, total minutes and total seconds.

Time & DurationOpen Calculator →

Hours Calculator

Add or subtract multiple hour-and-minute durations and see the signed total as hours, minutes, decimal hours and total minutes.

Time & DurationOpen Calculator →

Business Days Calculator

Count weekdays between two dates with inclusive counting options and optional U.S. Federal holiday exclusions using observed-day rules.

Work & ScheduleOpen Calculator →

Work Hours Calculator

Calculate total weekly work hours from selected workdays, shift start/end times and unpaid break minutes, including overnight shifts.

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Time Zone Calculator

Convert a local date and time between selected IANA time zones with daylight-saving-aware browser rules and ambiguous-time detection.

Time ZonesOpen Calculator →

Countdown Calculator

Calculate time remaining until a future local date and time from now or from a custom starting date and time, with a live countdown option.

Time & DurationOpen Calculator →

Day of Week Calculator

Find the weekday for a Gregorian calendar date plus day-of-year, quarter, leap-year status and weekend or weekday classification.

Dates & AgesOpen Calculator →

Week Number Calculator

Find the ISO 8601 week number, ISO week-year, Monday start date and Sunday end date for a selected calendar date.

Work & ScheduleOpen Calculator →

Unix Timestamp Calculator

Convert between Unix timestamps and readable UTC/local date-time values in seconds or milliseconds, with negative timestamp support where the browser supports it.

Time ZonesOpen Calculator →
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About Our Date & Time Calculators

This category brings together 12 live calculators for everyday calendar, duration and scheduling questions. The tools turn dates, times, work schedules and time-zone selections into clear results with understandable counting rules.

Dates & Ages

Calculate ages, compare dates, shift dates and identify calendar positions.

Time & Duration

Measure elapsed time, total hours, countdowns and timestamp values.

Work & Time Zones

Estimate business days, work hours and times across selected locations.

How to use these calculators

Select the calculator that matches your question, enter the requested dates or times and review the result together with its counting method. Choose the correct time zone and decide whether start dates, end dates, weekends or holidays should be included when a tool provides those options.

Why date and time results can differ

Results may vary because tools use different inclusive-counting rules, holiday calendars, time zones, daylight saving transitions or rounding conventions. Each calculator states the method used for its result.

Calendar note: Review the selected time zone, holiday calendar and inclusion rules before relying on a result for travel, payroll, legal deadlines or important scheduling.

Date & Time Calculator FAQs

Are these date and time calculators free to use?

Yes. All 12 calculators in this category are available as free browser-based tools.

Which date and time calculators are available?

The category includes age, date difference, add or subtract date, time duration, hours, business days, work hours, time zone, countdown, day of week, week number and Unix timestamp calculators.

Are all 12 calculator cards available now?

Yes. All 12 calculator cards link to their completed calculator pages.

Do these tools account for leap years?

Yes. Relevant calculators use normal calendar rules, including month lengths and leap years.

Can I use these calculators on my phone?

Yes. The category and calculator pages are responsive for phones, tablets and desktop screens.

Why might time-zone results change?

Daylight saving rules and historical time-zone changes can alter the offset for a selected date.

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