Time & Date Calculators
Time Duration Calculator

Time Duration Calculator

Use our time duration calculator to determine how much time has passed between two events. It is perfect for tracking work time for your business.

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4 hours 45 minutes 13 seconds


12 hours 12 minutes

Table of Contents

  1. Accurate Calculations
  2. The Convenience Is a Result of Our Odd Time Reckoning
  3. Calculating the Exact Age
  4. The system of division of time units
  5. Decimal or Metric time

Time Duration Calculator

Measuring time can be as easy as hitting start on a stopwatch. Simple time duration calculators can remove any chance of error, providing accurate conversions for work or amusement.

You can use this calculator on a single day or over several days. The two calculators above can help anyone calculate the days, hours, minutes, and seconds between any two points in time. There are two interfaces. The first calculates the duration between two points on the same day. The second is a "Time Between Two Dates" calculator.

The one-day time difference calculator is simple to use. Just enter the two times into the boxes provided. For convenience, the "now" buttons automatically enter the current time.

Once you hit "Calculate," the calculator will display results in four formats—hours, minutes, seconds, decimal hours, decimal minutes, and seconds.

The Time Between Two Dates calculator is likewise easy to use and convenient. First, enter the month, day, and year into the appropriate boxes. A calendar popup and a "now" button are to the right of the date boxes. If you know the exact times you would like the calculator to measure to and from, you can also enter those.

Once you enter the date and time, press "Calculate" for the results. The Time Between Two Dates calculator shows results in 5 formats – days, hours, minutes, seconds, decimal days, decimal hours, decimal minutes, and seconds.

Accurate Calculations

A time calculator is a quick, accurate, and convenient way to ensure you know exactly how much time has elapsed between two points. Businesses that employ hourly labor need impeccable timekeeping. Still, startups and sole proprietorships often need to cut costs and forego expensive management software. Therefore, an exact time duration calculator can be a money saver.

Tracking how long projects and individual tasks take is essential for some companies' bottom lines. For example, builders give time and cost estimates before contracting with clients.

Their estimates will be much less accurate if they don't keep careful records of time on task. Using a dedicated time-duration calculator is much quicker and more accurate than doing the math by hand or with a regular calculator.

The variable number of days in each month throws off some people's calculations. For example, suppose a business owner knows they received some materials on a specific day in February and that they lasted until a particular day in April. In that case, a calculator could tell them how many days the supplies last. Conveniently, the businessperson would not have to remember how many days are in February and March; they would need to enter the dates.

In addition to serious applications like tracking labor and calculating how long supplies last, many people want to measure time for educational or entertainment reasons. What student doesn't want to know exactly how many days of vacation they will have over the summer? If they know the dates of the last and first days of school, the calculator can tell them how many days they will enjoy themselves.

The Convenience Is a Result of Our Odd Time Reckoning

We further complicate time with our AM and PM designations. As a result, figuring out precisely how many hours have elapsed between 7:39 AM and 4:28 PM requires a lot of effort for most people. There are several steps the calculator performs instantly.

To start calculating the duration between the times listed above, you need to convert them to 24-hour time. So, for example, the time would not change at 7:39 AM, but it would change to 16:28 at 4:28 PM.

Calculating the Exact Age

The calculations are complicated because there are 24 hours in a day and varying numbers of days in each month. February can have either 28 or 29 days, depending on the year. Therefore, having an elapsed time calculator is a great way to save time and avoid mistakes when you need accurate timekeeping.

Suppose your elderly grandfather was told he was born at 2:26 AM on March 27, 1947. You could use that to determine his exact age down to the second. Add the date and time of his birth to the Time Between Two Dates calculator. Then, click "now" to set the current time. Once you hit "Calculate," you will learn that he has lived for over 2.3 billion seconds in his long life!

The system of division of time units

In ancient times, the Egyptians divided the daylight hours into 10 "hours" and added one hour at each end for sunrise and sunset. Thus, the day lasted 12 hours. They corresponded to 12 hours of complete darkness at night. Perhaps the Egyptians introduced this system because there are twelve lunar cycles in a year.

Night time was especially important to the Egyptians because it was at night that they carried out various religious ceremonies. This system included tracking the so-called Decans. Decans were 36 groups of constellations or single stars that appeared in the sky at a particular stretch of the night in a specific sequence.

The division of each hour into 60 minutes and minutes into 60 seconds came from ancient Babylon. The Babylonians used the sexagecimal (base-60) numbering system in mathematics and astronomy. Also, from Babylon came the division of the circle by 360 degrees.

Why sixty and not, for example, 10 or 100? The point is that it was easy to divide sixty by 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30 and get not a fraction but an integer. The Babylonians actively used this property of the number 60 in trade. This is why the sexagecimal system caught on in ancient Babylon.

Decimal or Metric time

In 1754, the French mathematician Jean-Baptiste le Rond d'Alembert suggested dividing all time units by ten. He decided that such a division would lead to simpler and more convenient calculations.

In 1788, French lawyer Claude Boniface Collignon proposed dividing a day into 10 hours, each hour into 100 minutes, each minute into 1,000 seconds, and each second into 1,000 levels. He proposed a week of 10 days and a year's division into ten solar months.

The French Parliament slightly modified this proposal. It decreed that the period from midnight to midnight be divided into ten parts, each part into ten others, and so on to the minor measurable portion of the duration.

These innovations became a part of a revolution in the general reckoning system. In addition to the new method of calculating hours, a republican calendar was also created. It divided the month into three decades of ten days. As a result, five days were left. They were placed at the end of each year.

The system officially went into effect on November 24, 1793. Midnight began at zero o'clock, and noon was at five o'clock. Calculations became simpler. People could write time in fractions; for example, 8 hours and 32 minutes could be written as 8.32 hours, and both values meant the same thing.

To help people switch to the new time format, watch manufacturers began producing clocks with dials showing decimal and old time. But people never switched to the new time. Decimal time proved unpopular and was abolished 17 months after its introduction.

The Republican calendar was abolished at the end of 1805.

In the 1890s, Joseph-Charles-François de Rey-Pailhade, president of the Toulouse Geographical Society, proposed using the decimal system. He divided the day into 100 parts, which he called cés. Each cé was divided into 10 decicés, 100 centicés, 1,000 millicés, and 10,000 dimicés.

The Chamber of Commerce of Toulouse passed a resolution in support of the proposal. But outside of that, the proposal did not receive adequate support.

In 1897, the French scientific committee of the Bureau des Longitudes put forward a similar proposal. It retained the 24-hour day but proposed dividing the hour into 100 decimal minutes. The minutes were divided into 100 seconds. This project also failed to gain approval.

It was the last major attempt to introduce decimal time in history.