Date & Time Calculators
Age, date differences, countdowns and time-duration calculators.
Calendar and clock arithmetic: exact ages, the number of days or working days between two dates, a date a given number of days away, time durations and worked hours, and time zones. Calendar maths is easy to get wrong by hand — months have different lengths, leap years add a day — and these tools handle that for you.
Which Date & Time calculator do you need?
- Exact age in years, months and daysAge CalculatorCalendar-accurate age on any date.
- Days between two datesDays Between Dates CalculatorCounts calendar days between two dates, with an option to include the end date.
- Working days between two datesBusiness Days CalculatorExcludes weekends from the count.
- The date a number of days from nowDate CalculatorAdds or subtracts days from any date and gives the day of the week.
- Hours worked in a shiftTime Card CalculatorClock-in to clock-out minus any unpaid break.
- The time in another cityTime Zone ConverterConverts a time between time zones.
Browse Date & Time Calculators by Type
Date Calculations
10 calculators
- Age Calculator
- Business Days Calculator
- Date Difference Calculator
- Day Counter
- Day of the Week Calculator
Time Arithmetic
7 calculators
- Decimal Hours Calculator
- Hours and Minutes Calculator
- Hours Calculator
- Minutes to Hours Calculator
- Seconds Calculator
All Date & Time Calculators
Is the end date counted?
"Days between" 1 and 10 March is 9 days, but if both days are part of a booking or a notice period you may need 10. Check whether your situation counts both ends — the days between dates calculator has an option for exactly this — because the same question explains most disagreements between date calculators.
Date & Time Calculator Guides
Adding and Subtracting Time: How the Time Calculator Handles Midnight Wraparound
The time calculator finds a new clock time by adding or subtracting a duration of hours and minutes from a start time, wrapping automatically past midnight and reporting whether the result lands on a different calendar day.
Read guideConverting Minutes to Hours as a Decimal: Quick Reference and Formula
Converting minutes to hours as a decimal figure is a straightforward division by 60, useful whenever a duration needs to be compared, summed, or billed in fractional hours rather than minutes.
Read guideConverting Seconds to Hours, Minutes, and Seconds: A Worked Example
The seconds calculator turns a raw second count into an exact hours/minutes/seconds breakdown plus decimal totals, and this article walks through two real conversions from its formula.
Read guideFrom a Week of Time Cards to a Single Day's Overtime Hours
Logging five real shifts through the Time Card Calculator produces a weekly total, but only feeding one long day's exact clock-in, clock-out, and break into the Overtime Hours Calculator shows where the overtime in that total actually came from.
Read guideHow 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.
Read guideHow 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.
Read guide