Understanding the diversity of calendars used around the world
Oct 15, 2026
Calendars. Today, when I'm uploading this video,
it is the 30th of December of the year 2022. Well,
at least in the calendar that I use.
The odds are that you, watching this video, also use it,
and that the date is exactly the same for you.
Well, you're likely not watching it on the day
of the upload itself, but you know what I mean.
However, for some people throughout the world,
days, months, and even years are different than for most.
Last year, around this time,
I made a video about how each month
of the Gregorian calendar got its name. You can check
the description for the link to it.
And we get to learn how August was named after Augustus,
the Roman emperor, how October was named after being the 8th month
when the Roman calendar only
had 10 months, among other names.
But these months and their names are only valid for the Julian and
then the Gregorian calendars.
And other calendars throughout the world use a different amount of
months as well as different names for each of them.
For instance, the upload date year of this
video is also 2022 but for some people it might be the year 2015.
Now obviously these people aren't
in some other dimension where time moves slower,
neither did they travel back in time and these
differences are simply due to the fact that time
is organized differently depending on where you
are in the world, which is why the day,
month or even the year might vary. The year issue is simple,
the Gregorian calendar dates our current age
to the birth of Jesus Christ, any other cultures that
don't will have a different year
as the origin point for their calendar.
In this video, we're going to quickly learn about
which different calendars exist, why
and how they are different,
by which countries and in which ways they are used.
First, let's define the different types of calendars that exist.
Calendars are usually one of three types, solar, lunar or lunisolar.
The names are somewhat self-explanatory.
Solar calendars are calendars whose dates indicate
the apparent position of the sun
relative to the stars.
The Egyptians appear to have been the first
to develop a solar calendar, using it as a
fixed point for the annual sunrise reappearance of the dark star Sirius
or Sothis in the eastern
sky, which coincided with the annual flooding of the Nile River.
They constructed a calendar of 365 days,
consisting of 12 months of 30 days each, with 5 days
added at the year's end.
It was tremendously similar to the calendar we use today.
The global Gregorian calendar, successor to the Julian,
introduced by the Romans which
divides the year into 12 months, some with 30 days and others with 31.
Another type of calendar is a lunar calendar,
whose months correspond to the cycles of the
moon phases instead.
The Islamic calendar is for instance a lunar calendar
and the Maori calendar as well.
But there are very few calendars worldwide,
especially in modern times, that are exclusively
most of the ones that aren't exclusively solar are lunisolar,
which is the third category of
calendars, precisely a mix of the two.
The biggest examples of which are the Chinese calendar,
the Hebrew calendar, or the Hindu calendar.
Their dates indicate both the moon phase and
the time of the solar year,
that is the position of the sun in the earth's sky. As with all
calendars, they divide the year into months,
but they have an additional requirement. Ordinary
years consist of 12 months but every second
or third year is what they called an embolismic year
which adds a 13th month. The logic is kind of the same
as regular calendars having a leap year where
you have an extra day except they have an extra month.
They also differ between themselves in some
details and while they take the moon phases into consideration they
also differ as to which day
is the first day of the month.
For the Chinese a month begins with the new moon, for some Hindu
calendars it begins with the day after the full moon
and some begin with the first sighting of
a lunar crescent. But these details aren't really relevant right now,
they just serve to show you
why calendars differ and why many exist even within the same type.
It's important to note
though that almost every country in the world has legally adopted
and accepted the Gregorian
calendar for convenience sake.
A globalized world kind of required everyone to be on the same date.
I think worldwide, only Afghanistan, Iran,
Ethiopia, and Nepal haven't legally accepted it.
But a lot of other places throughout the world continue
to use their lunar or lunisolar calendars
simultaneously to determine religious festivals and national holidays,
like the Rosh Hashanah from the Hebrew calendar, the Chinese New Year,
Buddha's birthday, Diwali in the Hindu calendar,
Ramadan, Eid al-Fitr
and Eid al-Adha in the Islamic calendar, among others.
So now that we've understood which types of calendars exist,
let's take a look at specific ways in which they differ.
We already saw the lunar and lunisolar calendars differ between them
depending on which phase of the moon they choose to start their months.
When it comes to solar calendars, there is a very large number
of them throughout history, roughly around 40.
The vast majority of them have fallen out of use,
or like I mentioned before, they're used simultaneously
with the Gregorian calendar just for religious purposes.
An example of a no longer used calendar
is the Byzantine calendar used by the Byzantine Empire
from 988 to 1453.
Its year started on the 1st of September, for instance.
Or the Bulgar calendar
used by the First Bulgar Empire,
which actually had a similarity with the current Chinese calendar.
It used a 12-year cycle that then repeated itself
and each year of each cycle was named after
different animals. After the French Revolution,
they also tried to implement a new calendar
beginning on year 1 with the revolution as the starting point.
This ended with the coronation
of Napoleon. And the most famous
no longer used solar calendar was the Julian calendar of the
Roman Empire which eventually became the Gregorian we have today.
After slight adjustments were made
to it, the Julian calendar was 13 days behind
the current Gregorian calendar. So besides this
calendar we all know today,
which other solar calendars are still used in modern times? The
Berber calendar is still used by some people in North Africa.
They are Arabic, however their
lunar Islamic calendar is not suitable for agriculture
because it doesn't relate to seasonal
cycles, so they started using this one,
which is ultimately a derivation from the Julian calendar.
The Coptic calendar is also still used by some.
It was actually official in Egypt until 1875,
being based on the ancient Egyptian calendar.
It has 13 months, 12 of 30 days each, and one at the
end of the year with 5 days or 6 in leap years.
Their celebration of Christmas, for instance,
takes place only on the 7th of January of our calendar.
This one is used by the Coptic
Orthodox Church. One of the most well-known
solar calendars still used today is also the
Ethiopian calendar,
which has 12 months of 30 days plus 5 or 6 epigominal days, which also
make a 13 month. And their years begin on the 11th
of September of our calendar. In addition,
they are 7 years behind.
According to a BBC article, this is because they calculate the
birth year of Jesus Christ differently.
In opposition, the Thai solar calendar adopted
by King Rama V in 1888 as the Siamese version
of the Gregorian calendar is 543 years ahead
because they date back the first year to the birth
of Buddha instead of Jesus. Also, in Iran,
they use their own calendar with a 33-year cycle
and they are currently in the year 1401. It
specifies the origin of the calendar to be the journey
of Muhammad from Mecca to Medina in the
Gregorian year of 622. Similar examples exist with lunar calendars.
The Islamic calendar itself is in
the year 1444. They have 12 lunar months
and are used in most Muslim countries to determine
religious holidays and rituals,
while the Gregorian calendar is used for civil purposes.
They also only have 354 days per year.
In Nigeria, the native Igbo people traditionally use
their own calendar with 13 months a year,
7 weeks per month and 4 days per week.
The Javanese people in Indonesia use 3 calendars,
the Gregorian for civil purposes,
the Islamic for Muslim holidays and then their own as well.
The time in which they begin counting is also different.
For instance, 2011 for us was 1944 for them.
And finally, the most well-known calendars used in parallel
with the Gregorian calendar are many of the lunisolar ones.
The Chinese is probably the best known used for traditional
Chinese holidays, such as their New Year and the Lantern Festival.
It also provides the traditional Chinese nomenclature of dates within
a year, which people use to select lucky days for weddings,
funerals, moving, or starting a business.
Days begin and end at midnight like us,
and months begin on the day of the new moon.
Years start on the second or third new moon after the winter solstice.
The length of a month is also
annotated as either just being long or short for 30
or 29 days respectively. Their years are
organized in cycles of 12,
I believe corresponding to their zodiac signs. Each of the 12 years has
an animal associated with it.
These animals are the dog, the pig, rat, ox, tiger, the year for 2022,
2022, rabbit the year for 2023, dragon,
snake, horse, goat, monkey, and rooster.
The year cycle, so if 2022 was the year of the tiger,
then it will be again in 2034.
There's also historical examples
of widely used lunisolar calendars that fell out of
use in modern times, like the Babylonian calendar,
but I'm not getting into those here.
Some countries, 18 to be precise,
also use their own civil calendars, simultaneously
with the Gregorian one.
Algeria, Bangladesh, Egypt, India, Iraq, Israel, Jordan, Libya and
Mauritania, Morocco, Myanmar, Oman, Pakistan,
Saudi Arabia, Somalia, Tunisia, the United Arab
Emirates and Yemen. We can't go into all of them
so let's look at two to understand some of the
differences. First, the Indian national calendar.
This is a solar calendar. I believe it's also
called Shaka Samvat and it is 78 years behind the Gregorian calendar.
They have 12 months which
also follow the signs of the tropical zodiac
and their weeks also have 7 days. Each are named after
a celestial body. Starting on Sunday it goes Sun,
Moon, Mars, Mercury, Jupiter, Venus and Saturn.
It seems all calendars end up being very similar in days
and months for each year,
just desynchronized from each regarding when each month starts.
And also the Hebrew calendar used
in Israel. It's a lunisolar one,
currently in the year 5782, used for religious purposes for
Jewish people worldwide,
but also the official calendar of the state of Israel. It apparently
also provides timeframes for agriculture,
as that may have been one of the purposes for which it was
created. Its year is about 11 days shorter than the solar year
and it uses the 19-year
metonic cycle to bring it into line with the solar year,
with the addition of an intercalary
month every two or three years.
Even with this intercalation, the average Hebrew calendar year
is longer by about 6 minutes
and 40 seconds than the current tropical year, so every 216 years,
they fall a day behind.
The era used for the calendar since the Middle Ages is Anomundi,
meaning from the creation of the world.
The epoch or origin point of this era is the movement when,
according to the Genesis creation narrative,
the world was created. Like I mentioned,
while the Gregorian calendar uses Jesus' birth as the origin,
the Hebrew use the date they believe
the world was created, just like other religious
calendars use other landmarks of their own.
In addition, throughout history and throughout the world,
there have been many different calendars by different civilizations.
The most well-known outside the solar lunar reality is probably
the Mayan calendar with a 260-day count and various cycles and
sequences being much harder to comprehend than the ones we have today.
But then again, that might be one of the reasons,
among various others, that these old calendars fell into disuse
and the Julian and then Gregorian calendar became common worldwide.
with the old local calendars simply being used for religious
or ceremonial aspects save a few
exceptions. So that is a quick overview of the types
of calendars that exist, how they differ
and who uses them. I didn't get into the history
and origin of each of them or many specific cases
that would take a longer video
but let me know in the comments if you're interested in a video
about a specific calendar more in depth like how
the Chinese calendar works or why did we switch
from the Julian to the Gregorian calendar.
Thanks so much for watching this video,
subscribe if you want, and I will see you next time
for more general knowledge.

