Date & Time Calculators

Date and time calculators for exact age, days between dates, adding days to a date, working and business days, live countdowns, time arithmetic and world time zones. They handle leap years, month-ends and daylight saving correctly.

Age CalculatorExact age in years, months and days from date of birth.Date CalculatorAdd or subtract days, weeks, months or years from a date.Date Difference CalculatorDays, weeks and months between two dates.Time CalculatorAdd and subtract hours, minutes and seconds.Countdown CalculatorLive countdown to any event or deadline.Working Days CalculatorWeekdays between two dates, excluding weekends.Business Days CalculatorFind a deadline N business days from a date.Time Zone ConverterConvert times between IST and world zones.

Which date or time calculator do you need?

You want to know…Use
How old someone is, or was, on a specific date (exam forms!)Age Calculator
How many days are between two datesDate Difference Calculator
What date it will be 90 days or 6 months from nowDate Calculator
How many working days fall in a periodWorking Days Calculator
The deadline 10 business days from todayBusiness Days Calculator
A live timer to an exam, wedding or launchCountdown Calculator
Total hours on a timesheet, or a shift that crosses midnightTime Calculator
What 9 PM IST is in New York or LondonTime Zone Converter

Calendar rules our calculators follow

  • Leap years: divisible by 4, except century years not divisible by 400 (2000 was a leap year; 2100 won’t be).
  • Month-ends: adding a month to 31 January gives 28 or 29 February, the convention banks and contracts use.
  • Inclusive vs exclusive counts: date differences exclude the end date by default, and working-day counts include both ends. Each page explains when to add 1.
  • Local dates: dates are read in your own time zone, which avoids the one-day errors some online tools make for users outside the UK.
  • Daylight saving: the time-zone converter uses your browser’s up-to-date IANA time-zone database. India has no DST, but the US, UK, Europe and Australia do.

Checking age eligibility on the cut-off date in UPSC, SSC, banking and state PSC notifications; counting notice-period days; planning leave around holidays; calculating loss-of-pay days; tracking days to board exams; and scheduling calls with colleagues abroad.