Date & Time Calculators

Age, date differences, countdowns and time-duration calculators.

Popular:Age Calculator Time Calculator Countdown Calculator World Clock Date Calculator Leap Year Calculator

Date Calculations

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Time Arithmetic

7 calculators

Countdowns

5 calculators

World Time

5 calculators

Date Arithmetic

3 calculators

Add Days to Date CalculatorAdd a number of days to a date to find the resulting calendar date and day of the week.Age CalculatorCalculate exact age in years, months, and days between a birth date and any reference date, using calendar-accurate date arithmetic.Birthday Countdown CalculatorFind how many days remain until your next birthday, and what age you'll be turning.Business Days CalculatorCount the number of weekdays (Monday to Friday) between two dates, inclusive of both endpoints.Countdown CalculatorCount the days remaining until a target date, or how many days have passed if it's already happened.Date CalculatorAdd or subtract a number of days from a date to find the resulting calendar date and day of the week.Date Difference CalculatorFind the exact difference between two dates in years, months, and days, using calendar-accurate arithmetic.Day CounterCount the number of days since (or until) a date — useful for tracking streaks, milestones, or how long something has been going on.Day of the Week CalculatorFind what day of the week any date falls on — past, present, or future.Days Between Dates CalculatorCount the number of days between two dates, with an option to include the end date.Days in Month CalculatorFind how many days are in any month of any year, plus which day of the week it starts and ends on.Decimal Hours CalculatorConvert between decimal hours (like 7.5) and H:MM time format (like 7:30), in either direction — just enter either format and it auto-detects which one you used.Epoch ConverterConvert an epoch time (seconds since 1 January 1970 UTC) into a readable date and time.Event Countdown CalculatorCount the days remaining until a specific event, like a wedding, exam, trip, or launch date.Fiscal Year CalculatorFind which Indian fiscal year (April to March) a date falls in, its fiscal quarter, and how far through the fiscal year it is.Hours and Minutes CalculatorFind the duration between two clock times, shown as a whole-hours-and-minutes breakdown.Hours CalculatorCalculate the total number of hours between two clock times, shown as a decimal figure.Leap Year CalculatorCheck whether a year is a leap year, and find the nearest leap years before and after it.Minutes to Hours CalculatorConvert a number of minutes into hours (as a decimal figure).Month CalculatorFind the total number of whole calendar months between two dates.Overtime Hours CalculatorSplit a shift's worked hours into regular and overtime portions against a standard-hours threshold.Pomodoro TimerCalculate the total time a Pomodoro work session will take, including short and long breaks.Quarter CalculatorFind which calendar quarter (Q1-Q4) any date falls in.Retirement Countdown CalculatorFind your retirement date and how many days remain until it, based on your date of birth and retirement age.Seconds CalculatorBreak down a total number of seconds into hours, minutes, and seconds.Shift Hours CalculatorCalculate hours worked in a shift, including overnight shifts, minus any unpaid break.Sleep Time CalculatorFind the best times to go to bed based on when you need to wake up, using 90-minute sleep cycles.Subtract Days from Date CalculatorSubtract a number of days from a date to find the resulting calendar date and day of the week.Time CalculatorAdd or subtract hours and minutes from a time of day, with automatic wraparound past midnight.Time Card CalculatorCalculate worked hours for a shift from clock-in and clock-out times, minus any unpaid break.Time Duration CalculatorFind the duration between two clock times, including overnight spans that cross midnight.Time Until CalculatorFind how much time is left until any future date.Timestamp ConverterConvert a numeric timestamp (seconds since 1 January 1970 UTC) into a readable date and time.Time Zone ConverterConvert a time of day between major world time zones, such as IST, UTC, EST, and JST.Unix Timestamp ConverterConvert a Unix timestamp (seconds since 1 January 1970 UTC) into a readable date and time.Wake Up Time CalculatorFind the best times to wake up based on your bedtime, using 90-minute sleep cycles.Week Number CalculatorFind the ISO 8601 week number for any date.Working Days CalculatorCount the number of working days (Monday to Friday) between two dates, inclusive of both endpoints.World ClockSee the equivalent time in several major world time zones at once, from a single reference time.Year CalculatorFind the total number of whole years between two dates.

Date & Time1 min read

How a Calendar-Accurate Date Difference Is Calculated

A calendar-accurate date difference breaks the gap between two dates into whole years, whole months, and remaining days — a more human-readable answer than a single total-day count, using the same month-end-clamping logic as the Age Calculator.

Date & Time1 min read

How a Countdown to a Future Date Is Calculated

A countdown is just the signed difference in days between a target date and a reference date — positive while the event is still ahead, and a "days ago" figure once it has already passed.

Date & Time1 min read

How a Countdown to Any Date Is Calculated

A countdown is simply the number of calendar days between a reference date and a target date — positive when the target is still ahead, negative (shown as "days ago") once it has passed.

Date & Time2 min read

How a Raw Timestamp Becomes a Real Countdown to an Event

A launch date buried in an API response as a raw Unix timestamp converts to a real calendar date, and that same date, fed straight into the countdown calculator, produces the exact same 110-day countdown as typing the date in directly.

Date & Time1 min read

How a Unix Timestamp Converts Into a Readable Date

A Unix timestamp is just a count of seconds since 1 January 1970 UTC — adding that many seconds to the epoch gives the exact date and time it represents, in UTC.

Date & Time1 min read

How Adding or Subtracting Days From a Date Is Calculated

Adding or subtracting days from a date is calendar-aware day-by-day arithmetic — correctly rolling over month and year boundaries, including February's leap-year length, rather than a simple fixed-length addition.

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