Number of weeks in a year is a frequently searched question. There are 52.143 weeks in a regular year. A regular year in the annual calendar has 365 days that is divided by 7 (days in a week) to calculate the number of weeks in the year. In the leap year that comes after every four years, one extra day is added making it 366 days in the year.
How many weeks in a year?

There are two types of years, the regular calendar year and the leap year. So most of the people often want to know that how many weeks in a year, either its regular year or leap year.

There are 52 number of weeks in a year. Although the leap year adds an extra day, yet it’s generally considered as same for a normal year and leap year.

In the case of a leap year, total days are considered as 366, and the number of weeks is calculated by dividing it by 7. The number 7 stands for the number of days in a week.

By dividing 366 by 7, the number of weeks comes out to be 52.285 that is simply considered as 52.
Gregorian calendar
These calculations are according to the Gregorian calendar that was first introduced in the 16th century. In the Gregorian calendar, the year completes in 365.24 days and the number of weeks in a year is 52.18 when 365.24is divided by 7.
Calculation of number of weeks in a year
The number of weeks in a year can be calculated accurately by the following method:
Number of weeks in a normal year
Total days in a year = 365
Total days in a week = 7
Total number of weeks in a year = 365 / 7.0 = 52.14 weeks

Each year, one extra day is added to the number of days in the previous year. One normal calendar year consists of 365 days with the addition of 1 day. The number of weeks is calculated and then 1 is added to it.

1 regular year is equal to 365 days and there are 7 days in a week. The number of days (365) is divided by the total days in a week (7). It results in 52.14 weeks in a year. When 1 extra day is added in these weeks it completes one regular year.
Number of weeks in a leap year
Leap year comes every four years and there is one extra day in that year than the regular years. February has an extra day and that makes it a month with 29 days instead of the regular 28 days.
Number of weeks in a leap year can be calculated as:
Total number of days in a leap year = 366 (1 extra day than the regular year)
Total number of days in a week = 7.0 days
Total weeks in a leap year = 366 / 7.0 = 52.28 weeks

As a leap year occurs every 4 years, except the years that can’t be completely divided by 400 and are divided by 100.

So, as according to the above calculations, there are 366 days in a leap year, and each year there is an extra day.

There are two extra days in a leap year instead of 1 in a regular calendar year. So, the calculation will be 52.28 weeks + 2 days for a leap year.
Why don’t we have 48 weeks per year?
As a common observation, we find that each month is considered to have four weeks. Now one can have a question in his mind that if we have four weeks in a month and there are a total of 12 weeks in a year, then the number of weeks will be:
Number of weeks in a month = 4.0
Number of months in a year = 12
Number of weeks in the year = 12 multiplied by 4.0 = 48

But there is yet another confusion that if there are four weeks in a month, then the week should be consisting of 28 days in total.

Hence, there will be a need to lengthen the week by adding 0.6 days in each week just to meet the 365 days in a year.
For example,

If there are 7.6 days in a week, and 48 weeks in a year, there will be 364.80 days in the year. To make this adjustment, a 24 hours day can be elongated to 26 hours.

But it is actually impossible to adjust a day according to our own will, by adding or deleting few hours in the regular 24 hours that is the time between one sunrise to the next one.

There is an average of 4.34 weeks in each month by adding 1 or 2 days in a month.
Summary
There are approximately 52 weeks in a year. Precisely calculating, there are 52.14 weeks in a regular year and 52.28 weeks in a leap year. Leap year comes every 4 years and adds an extra day to the regular 365 days.
What if we have 8 days in a week?
Instead of whirling about 7.6 if we consider 8 days in a week and there are 48 weeks in a year, then the calculation will end up in the 384 days in a year:
Number of days in a week = 8
Number of weeks in a year = 48
Number of days in a year = 48 multiplied by 8 = 384 days
So, 384 days are not the actual number of days in a year. So, we end up with a total of 52 weeks in a year instead of 52.143 or 52.244, etc.
What if we have 13 months in a year?

One can think that instead of adjusting the hours or days, why don’t we have 13 months in a year and 48 weeks in a year. It will simply end up in having the 364 days that is the ultimate number of days.

In this way, we can have 3 years of the 364 days and a leap year with 369 days. But if these calculations are made, leap year would have not been of the 48 number of weeks.

However, we have a regular calendar in which the month is consisting of 30 or 31 days, except the month of February.

If we add these one or two days in each month, it will increase the number of weeks approximately reaching 52 weeks. Four weeks in a month is an approximate thing and not the ultimate one.

Extra one or two days can not be considered as a week so they are not counted generally. Yet they are the part of the month and are added in the total number of days in a year.
Number of weeks in different months
Each month in the year is having a different number of days in addition to the regular four weeks. The number of days in a month have been mentioned below:
Month  Details 

January  Total days = 31 days (four weeks + 3 days) 
February  Total days = 28 days in regular year and 29 days in leap year 
March  31 days (four weeks + 3 days) 
April  30 days (four weeks + 2 days) 
May  31 days (four weeks + 3 days) 
June  30 days (four weeks + 2 days) 
July  31 days (four weeks + 3 days) 
August  31 days (four weeks + 3 days) 
September  30 days (four weeks + 2 days) 
October  31 days (four weeks + 3 days) 
November  30 days (four weeks + 2 days) 
December  31 days (four weeks + 3 days) 
Number of weeks in different years
Some years are leap years while others are not. Here are some years with the number of weeks in each year.
Year  Weeks  Year 

2014  52.0 weeks + day  Regular 
2015  52.0 weeks + day  Regular 
2016  52.0 weeks + day  Leap 
2017  52.0 weeks + day  Regular 
2018  52.0 weeks + day  Regular 
2019  52.0 weeks + day  Regular 
2020  52.0 weeks + day  Leap 
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To the point
Leap year can be found in two ways, first rule is that the number consisting of the last two digits should be divisible to 4. In the second rule, the first two digits in a century should be divisible to 4. There are 52 working weeks in a year.
Frequently asked questions
People have various confusions in understanding the number of days and number of weeks in a year. To satisfy their queries, some of the questions have been answered below:
1. Are there 52 number of weeks in every year?

As a common fact, there are 12 months and 52 weeks in a year. These 52 weeks constitute a total of 365 days in the year.

If we calculate the number of days according to 52 weeks, there will be 364 days. It means that there is an extra day in the total number of days, to be 365 days.

While in the leap year, there are two extra days instead of one day as happens in the regular year. Theis leap cycle according to the Gregorian calendar, there are 97 leap days in the 400 years that constitute the total number of weeks as 20,871 weeks.
2. How many weeks exactly are in a year?
There is 52.18 number of weeks in a regular year. Each month consists of approximately 4.35 weeks and an ISO year consists of 52 or 53 weeks. It makes a year of 364 days or 371 days in place of 365 or 366days present in the regular year or leap year.
3. Which country has 13 months in a week?

As all countries follow a regular twelve months calendar, Ethiopia is a country that follows the thirteen months calendar. Ethiopia is seven years behind all other countries of the world.

Ethiopia is a 3rd world country present in East Africa and is a symbol of ancient traditions. It has about 50% literacy rate and mostly following Abrahamic religion.
4. What are 13 months in Ethiopia?

In contrast to the rest of the world that follows a 12 months calendar, Ethiopia is the country that follows the 13 months calendar.

The 13th month in the Ethiopian calendar is called Pagume. In the Greek language, Pagume is aroused from Epagomene that means forgotten days while calculating a year.

According to the Ethiopian calendar, one year consists of 365 days, 6 hours, 2 minutes, and poor twentyfour seconds.
5. Why does February have 28 days?

February is the only month that has 28 days in a regular year and 29 days in a leap year. This happens due to a clear mathematical rule that the addition of an even quantity (e.g. 12 months) having odd numbers results in an even number.

So, Numa Pompilius (Great king of Rome) selected the month of February to host the Roman traditions to honor the dead. February was considered as the unlucky month and decided to have 28 days.
6. Who invented leap year?

Julius Caesar is the person who invented the leap year. Leap year comes every four years and adds an extra day to the regular 365 days in a regular year.

Leap days were included for the very first time into the Julian calendar in 46 before Christ by Julius Caesar (a former Roman general) at the advice of Sosigenes of Alexandria, a Greek astronomer.
7. How many hours in a year?
There is a total of 8766 hours in a year. The number of hours is calculated in the following ways:
Total days in a year = 365
Total hours in a day = 24
Total number of hours in a year = 365 days x 24 hours = 8760 hrs
However, the leap years have an extra day, so 24 hours will be added in 8760 hours of a regular year. But the year is not exact 365 days, so a middle way is to consider the 365.2 days and the number of hours is 8766 in each year.
8. How many working weeks in a year?
Generally, there are 52 working weeks in a year. But sometimes, you may get a salary for two excessive weeks according to the hourly rate of your employment or you work for two extra weeks in the year, then the total weeks are 52. If we assume a total number of hours as 40 every week, it becomes equal to 2,080 hours per year.
Conclusion

Number of weeks in a year is a most commonly asked question by people because there are two types of years, regular calendar year and the leap year.

There are approximately 52 weeks in a year. However, it’s a general number that is used instead of 52.143 weeks in a regular year and 52.24 weeks of a leap year

Leap year comes every four years and there is one extra day in the total number of days e.g. 365 days. There are additional 24 hours in the leap year and hence the number of weeks becomes 52.24.
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