Check your calendar and find out how many days each year has? Different types of calendars, such as Islamic calendar, Lunar calendar, Gregorian calendar have different numbers of days and months in a year. Each year in the gregorian calendar except for a leap year has 365 days. A leap year occurs every four years and has an extra day in February. The extra day in a leap year is to make up for the shortfall in the other three years because the earth takes 365 1/4 days for each revolution.

The subject becomes perhaps a little less confusing when you

look at it from a slightly different angle:

The "year" is not what we print on calendars. The "year" is the

time the Earth takes to complete one revolution around the sun ...

roughly 365-1/4 days.

The moon's revolution is not tied to the Earth's revolution in any

way. The moon does its own thing in its own orbit, and shows a

complete set of "phases" in roughly 29.53 days.

The reason so many cultures have made so many different

calendars is because no calendar can exactly match the sun

and the moon with whole numbers of days, and each calendar

tries to come close, in a different way.

Everybody's calendar does the best it can to fit the year.

And every calendar also has some structure that also goes

along with the moon ... some more closely, and some less.

The Gregorian calendar that we use does a very good job

matching the year, and then the "months" kind of give the moon

some recognition without really trying to match it closely.

The Islamic, Hebrew, and Chinese calendars begin their months

with the New Moon. The Islamic religious calendar ... as

I understand it, but I may be wrong ... is strictly lunar. It simply

begins a new year after 12 complete cycles of moon phases.

That makes the Islamic religious calendar about 11 days shorter

than Earth's revolution around the sun, and is the reason why

you'll notice Ramadan starting earlier every year than it did

the year before.

The Hebrew religious calendar is also strictly lunar, but with a big

additional device that brings it into alignment with the year.

The Hebrew religious months begin right on the New Moon,

so 12 of them are about 11 days shorter than a real year.

Then ... seven times in each 19 years ... the Hebrew religious

calendar adds an extra whole month/moon, and has 13 of them

before the next year is counted. This actually does a great job

of matching up with both the sun and the moon. The system

has been in place for over 2000 years, and it has worked out

such that ... without any special tampering ... Passover and

Sukkot (Tabernacles) always begin on the 15th of the month,

which is always the night of the Full Moon that is nearest the

respective Equinoxes.

By the way ... Most Islamic countries use the Islamic calendar for

prayer and religious applications, and the Gregorian calendar for

trade and business dealings. Israel and other Jewish communities

worldwide use the Hebrew calendar for prayer and religious occasions,

and the Gregorian calendar for trade and business dealings.