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Time & Date Calculator

Online time and date calculator helps to add years, months, weeks, days, hours, minute, and seconds to a certain day and time, or to subtract them from a certain date or time.
Input date and time in the left boxes, choose the operator in the middle, enter numbers of time units in the right boxes, and click the "Calculate" button.

Start Date &/Or Time:

  • Month










  • year(s)












1. History of calendars:

The first recorded calendars date to the Bronze Age, dependent on the development of writing in the Ancient Near East, the Egyptian and Sumerian calendars.

The Gregorian calendar was introduced as a refinement of the Julian calendar in 1582 and is today in worldwide use as the de facto calendar for secular purposes.

2. History of timekeeping devices:

The current sexagesimal system of time measurement dates to approximately 2000 BC, in Sumer. The Ancient Egyptians divided the day into two 12-hour periods, and used large obelisks to track the movement of the Sun.

The earliest known clock with a water-powered escapement mechanism, which transferred rotational energy into intermittent motions, dates back to 3rd century BC ancient Greece.

The first mechanical clocks, employing the verge escapement with a balance wheel timekeeper, were invented in Europe at around the start of the 14th century, and became the standard timekeeping device until the pendulum clock was invented in 1656.

More Information: More about Time    More about Date