Date Calculator

Sometimes we do things out of curiosity, and sometimes we do something out of necessity. Calculating dates is one of those things that fall into both categories.

Whichever type of calculation it is, everyone eventually finds that they need to calculate between two dates for one reason or another. In the time approaching summer vacation, kids want to know how long until the holidays. People want to know how many days until traditional U.S. holidays like Independence Day or Thanksgiving. Travelers need to know when their travel visa is going to expire.

Celebrations

Suppose it is January 23 and your significant other's birthday is April 5. In that case, you have 72 days (73 in a leap year) to plan their surprise party. But how do you figure out the days between dates? Do you work it out in your head?

January has 31 days, so 31 minus 23 means there are 8 days to start. February (it's not a leap year, is it?) has 28 this year, and then March has 31, plus 5 more in April. So, let’s see... 8 + 28 + 31 + 5 = 72.

That seems needlessly tricky and fraught with opportunities to forget how many days there are in a particular month or make calculation errors. Instead, you can use a date calculator. You don't need to know if it's a leap year.

When you open the date calculator for the first time, the calculator will fill in the current date in both the Start Date and End Date boxes. If you want to know how many days until that birthday, change the second box to the birthdate and press the Calculate button.

The Right Gift

Conversely, suppose you want to know how long ago someone's last wedding anniversary was. In that case, this calculator will help make the calculation. Set the end date to today and the start date to the previous anniversary.

There are symbolic materials associated with each year's wedding celebration. Therefore, it will not be out of place for you to know exactly what anniversary is being celebrated this time and what gift to give this year.

Retirement

If you're going to retire this year, you may want to know how many more days you have left until that big day. You can use an extra feature of the calculator found in the Settings button next to the Calculate button.

When you click Settings, you can decide not to count holidays where you get the day off. You can exclude any special days not listed just by adding them at the bottom—that might be your vacation time, for example. Click the calculate button and know how many days until you're free!

Innumerable Calendars

Each society in human history has had some formalized time-tracking method.

The world's oldest calendar, the lunar calendar, was found at Warren Field, Scotland. It was created about 8,000 years B.C. Hunters kept it to keep track of the annual migrations of animals. Hunters used the information from this calendar to provide themselves with food. The variations between calendars were significant and based on what each society thought was important.

The older calendars were inaccurate until Julius Caesar officially made the year 365 days long. He also added the leap day every four years to keep it synchronized with the seasons. He disconnected the lunar period from the months because the solar calendar ruled the seasons, which was more important to him.

The new calendar was still not perfect, but it served for a long time, from 45 B.C. to 1582. Pope Gregory XIII changed it by adding a new rule. Years divisible by four were considered leap years unless divided by 100. But there was an additional caveat: these years could be leap years if they were also divisible by 400.

When we live by the Gregorian calendar, sometimes we do not even think other calendars are used in parallel with it in some countries. They have their roots in the religions of these countries. And many of them are older than the Gregorian calendar.

Islamic, Muslim, or Hijrah calendar

The Islamic calendar is a lunar calendar. It employs a leap year system within a 30-year cycle, where 11 years are leap years with 355 days, and 19 years are common years with 354 days. The leap years in this cycle are determined by a specific pattern, approximately every 2 to 3 years. Therefore, a year in the Islamic calendar consists of 12 lunar months but alternates in length between 354 and 355 days. Due to the lunar year being shorter than the solar year by about 10 to 12 days, the Islamic New Year shifts annually with respect to the Gregorian calendar.

The months of the Islamic calendar shift in relation to the seasons. For instance, the Islamic calendar months that fall in some years in summer, after a while, will fall in winter, and vice versa.

The calendar is based on the Hijrah, the date on which the Prophet Mohammed and the first Muslims left Mecca for Medina, which happened in 622. Therefore, in Muslim countries, the calendar is called the Hijrah calendar. In 2022 of the Gregorian calendar, Muslims celebrated the 1444th year according to the Hijrah calendar.

Each new month begins when the lunar crescent moon is first visible to an observer after the new moon. A day in the Islamic calendar begins when the sun sets.

In Muslim countries, the Islamic calendar is used primarily for religious purposes and the Gregorian calendar for civil purposes.

Hindu calendar

The Hindu calendar is one of the lunar-solar calendars traditionally used in the Indian subcontinent and Southeast Asia. Different regions have their own variations of this year, which are more oriented to the lunar or solar cycle. For example, the Shalivahana Shaka, found in southern India, and the Vikram Samwat, found in Nepal and the northern and central regions of India, are oriented to the lunar cycle. Their new year begins in the spring.

Regions such as Tamil Nadu and Kerala focus more on the solar cycle. These calendars are called Tamil calendars.

The Gregorian calendar adds extra days to the month to correct the discrepancy between the twelve lunar cycles of 354 lunar days and almost 365 solar days. And the Hindu calendar retains the integrity of the lunar month. But it inserts an additional month, calculated according to complex rules, once every 32–33 months. In this way, the Hindu calendar ensures that the festivals and rituals associated with the harvest fall in the appropriate season.

Hindu calendars have been used in the Indian subcontinent since Vedic times. They are still used by Hindus worldwide, especially to set dates for Hindu festivals. The Hindu calendar is essential for practicing Hindu astrology and the zodiacal system. It can also be used for observing special religious days and fasting.

Buddhist Calendar

The Buddhist calendar is a lunisolar calendar primarily used in countries with Theravada Buddhist traditions, such as Cambodia, Laos, Myanmar, Sri Lanka, and Thailand. It is based on the traditional Buddhist era, which is dated to 543 years before the Gregorian calendar. This means that the year 2022 in the Gregorian calendar corresponds to the year 2565 in the Buddhist calendar.

This calendar is structured around the phases of the moon but also takes the solar year into account, making it lunisolar. A typical year in the Buddhist calendar starts on the first full moon day of the month, which usually falls in late January or early February. This aligns the calendar closely with other lunisolar calendars used in the region, such as the Hindu and traditional Burmese calendars.

Months in the Buddhist calendar begin on the day of the full moon, and their length alternates between 29 and 30 days, following the moon's synodic cycle. The calendar often includes a leap month approximately every three years to reconcile the lunar months with the solar year, ensuring that festivals and important religious observances fall in the correct season.

In addition to its religious significance, the Buddhist calendar is also used for traditional and cultural purposes in the aforementioned countries. It plays a crucial role in setting dates for Buddhist festivals and observances, which are integral to the cultural and spiritual life in these regions.

Chinese calendar

The Chinese calendar is a lunar-solar calendar. It is calculated on the basis of the position of the Sun and the Moon.

The Chinese calendar has twelve months of twenty-nine or thirty days, each of which begins on the first day of the new moon. It takes about 29.5 days for the moon to orbit the Earth, which the Chinese believe is one month. This is why each month begins on the day of the new moon.

Years begin on the second or third new moon after the winter solstice. A normal year consists of 12 months and 353–355 days, while a leap year has a whole extra month, which increases the year to 383–385 days. The normal Chinese year is 11 days shorter than the Gregorian calendar year. Therefore, the traditional Chinese calendar adds an extra month every 3 years to make up for the remaining 33 days.

The Chinese calendar determines the dates of important holidays like Chinese New Year and the Chinese Lantern Festival. It is used to select auspicious dates for weddings, funerals, moving, and starting a business.

Each year is associated with one of the five elements: wood, fire, metal, earth, and water. These are associated with the ten "heavenly trunks" of the year, which are essential in Chinese philosophy.

The second component of the year is the "earth branch." It represents the name of one of the twelve animals. These animals are the rat, the bull, the tiger, the hare, the dragon, the snake, the horse, the sheep, the monkey, the bird, the dog, and the pig. The characteristics of a year are a combination of one of the five elements and one of the twelve animals. Thus, the cycle of years begins every 60 years again.

The Chinese pay attention to how certain animals get along better than others. Therefore, parents choose a particular year for the birth of a child, as they believe that the right combination of animals can bring prosperity. When entering a romantic relationship, the Chinese also look to the celestial branch and the compatibility of future partners' signs.

In China, they believe that some animals are luckier than others. For example, the dragon symbolizes power, strength, and wealth. That is why the birth rate in China, Hong Kong, and Taiwan increased in 2012 (the year of the Dragon). On the other hand, the tiger is undesirable because of its erratic temperament. In many regions of China, there has been a sharp decline in the birth rate during these years.

Hebrew or Jewish Calendar

The Jewish calendar is lunar, with each month beginning with a new moon. Each date falls on the same phase of the moon. A year can have 6 different durations. A proper year can have 354–384 days, a sufficient year can have 355–385 days, and an insufficient year can have 353–383 days.

The length of a Jewish year (whether it is correct, sufficient, or insufficient) is determined by the day on which the 1st day of the month of Tishrei (Rosh Hashanah, that is, the New Year) falls. The New Year can only begin on Monday, Tuesday, Thursday, or Saturday.

The previous year is lengthened by one day if necessary for the new year of Rosh Hashanah to fall on the right day of the week.

In 2022, Jews celebrate the new year 5783 according to the Jewish calendar.

According to this calendar, they celebrate Jewish holidays, read the relevant chapters of the Torah in synagogues, celebrate birthdays and memorial days of deceased relatives, and put dates on official and commercial documents.

Iranian calendar

The Iranian or Persian calendar has been called "one of the most accurate calendar systems in the world." It is also called the Solar Hijrah. Like the Islamic calendar, it dates back to the Hijrah of the Prophet Muhammad in 622 A.D., but otherwise, it is quite different. It is a solar calendar, not a lunar calendar.

The Iranian year begins on the day of the vernal equinox, on Nowruz, the spring festival. The date of this holiday is determined by astronomical observations at the meridian of Tehran time.

The calendar has twelve months, of which the first six have thirty-one days, the following five have thirty days, and the last month may include 29 days in a normal year and 30 days in a leap year.

This calendar is now in official use in Iran and Afghanistan.

Ethiopian calendar

Ethiopia celebrated the new millennium on September 12, 2007. This is because the country uses a special Orthodox calendar. This calendar is used in Ethiopia by civilians, by the Ethiopian and Eritrean Orthodox Churches, the Eritrean Catholic Church, and the Evangelical Church of Eritrea.

The Ethiopian calendar is based on an older Coptic calendar. This Coptic calendar, in turn, is derived from the ancient Egyptian calendar. The Ethiopian calendar contains 12 months of 30 days each, plus five or six extra days at the end of the year, usually allocated as a separate 13th month. The number of extra days in a year determines whether it is a simple or leap year.

The twenty-four hours do not begin at midnight but with the sunrise.

Some Ethiopian calendars indicate a date based on both the Orthodox and Gregorian calendars to avoid confusion between the Orthodox and Gregorian calendars.

Balinese Calendars

Bali has two traditional Balinese calendars, Saka and Pawukon. They are used to determine the days of traditional festivals and ceremonies. For civilian purposes, the Gregorian calendar is used on the island.

The Saka calendar mainly determines the date of the Balinese New Year, called Nyepi. Before Nyepi, the Balinese hold colorful festivities. They carry huge effigies of evil spirits around the island and raise a ruckus. Nyepi Day is a day of silence. On Balinese New Year's Day, people can't turn the lights on, use electricity, leave the house, or entertain. Even Bali's airport is closed on this day, and most users have their internet turned off. It is believed that on this day, you should meditate and rethink the past year's events.

The new year on the Saka calendar occurs the day after the first new moon of the vernal equinox. That is why the holiday does not have a permanent date in the Gregorian calendar. As a rule, Nyepi falls in March. In 2022, the Balinese celebrated 1944 on the Saka calendar.

The second calendar is called Pawukon. The Pawukon is used by the Balinese to measure most religious ceremonies on the island. This calendar was introduced to Bali in the 14th century by the Javanese Majapahit dynasty, who migrated to Bali and brought their culture, traditions, and power there.

Pawukon does not have a countdown of years. One year on the Pavukon calendar has 210 days. Instead of months, the division is by weeks. Each seven-day week is named according to its order in the Pawukon year.

There are ten kinds of weeks in the Pawukon year. This calendar has weeks of 1, 2, 3 days, and so on up to 10. They all run almost simultaneously, with the days of some weeks overlapping with the days of other weeks and the intersection of important days forming holidays.

The three-day week, the five-day week, and the seven-day week are the most important for assigning holidays. The three-day and Friday weeks became important because they indicated market days in Java and Bali. The markets in Bali took place every three days and in Java every five days. This is how these cycles, or three-day and Friday weeks, came to be.

The Takeaway

Calendars measure the passage of days, months, and years, but they do more. They help us plan our daily activities, keep us organized, keep track of events, and enhance our productivity.

How many days are left to complete a book report, submit a business proposal, or plan that vacation? How long have you been married, happily single? How long is it until your 18th birthday, 45th anniversary, or second date?

Wall calendars haven't been so popular since the introduction of smartphones. Most people purchase them to decorate their otherwise featureless cubicles in their tedious jobs. The built-in calendars and apps like Google Calendar are a ready replacement with additional functionality to simplify life. Still, most of them won't give you a countdown saying how many days until an event.

How often have you set an appointment reminder for one hour before it occurs, only to find yourself in the next city with no chance of arriving on time? Using a date calculator keeps you aware of your events.