Calculation method of leap year

Simple calculation method of leap year in Gregorian calendar (a year that meets one of the following conditions is a leap year)

1。 Divisible by 4, but not by 100.

2。 Divisible by 400.

Details are as follows:

Leap year refers to the year with leap day in Gregorian calendar or summer calendar, and the year with leap month in China lunar calendar.

The period of the earth's orbit around the sun is 365 days, 5 hours, 48 minutes and 46 seconds (365.438+09 days), which is the tropic of cancer. The Gregorian calendar has an average of only 365 days a year, which is about 0.2422 days shorter than the tropical year, and accumulates about one day every four years. Add this day to the end of February (February 29th), so that the calendar year of that year is 366 days, and this year is a leap year. According to a leap year every four years, the average annual increase will be 0.0078 days, which will be about 3 days after 400 years. So every 400 years, there will be three leap years. Therefore, it is stipulated that the Gregorian calendar year is a whole hundred years, and it must be a multiple of 400 to be a leap year, and a multiple of 400 is not a normal year. For example, 1700, 1800 and 1900 are normal years, and 2000 is a leap year. The calculation of leap year comes down to what is commonly said: leap every four years; Do not leap for one hundred years, and then leap for four hundred years; Do not leap in a thousand years, and leap again in four thousand years; Never leap in 10,000 years, and leap again in 500,000 years.

How to calculate leap year?

Jump in four years, not in a hundred years, and jump again in four hundred years.

It is stipulated that the Gregorian calendar year is a whole hundred, leap year must be a multiple of 400, and the average year is not a multiple of 400. See Encyclopedia for details: leap year, year with leap day in Gregorian calendar or summer calendar, and year with leap month in China lunar calendar.

The period of the earth's orbit around the sun is 365 days, 5 hours, 48 minutes and 46 seconds (365.438+09 days), which is the tropic of cancer. The Gregorian calendar has an average of only 365 days a year, which is about 0.2422 days shorter than the tropical year. The remaining time is about one day in four years, plus February of the fourth year, making the calendar year of that year 366 days, and this year is a leap year.

The current Gregorian calendar has 97 leap years every 400 years. The average summer calendar is only 354 days a year, which is 0.367 1 day shorter than the 12 months of the lunar calendar. In order to make the first day of each month coincide with the new moon, it is stipulated that the end of 1 1 year will increase by 1 day every 30 years. This calendar year has 355 days, which is a leap year.

As a kind of China lunar calendar, the number of days in each month depends on the monthly deficit, and the time of one year is based on 12 months, and the normal year is about 1 1 day less than a tropical year. In order to close the earth's orbit around the sun, that is, the tropic year, one month is added every two to four years, and the added month is a leap month.

The year with leap month is 13 months, and the calendar year is 384 or 385 days. This year is also called leap year. According to a leap year every four years, the average annual calculation will be 0.0078 days, and it will increase by about 3 days after 400 years. So every 400 years, there will be three leap years.

Therefore, it is stipulated that the Gregorian calendar year is a whole hundred, the leap year must be a multiple of 400, and the average year is not a multiple of 400. That is what we usually say: leap in four years, not in a hundred years, and then jump in four hundred years.

Simple calculation method of leap year in Gregorian calendar: Set year if (year can be divisible by 4, but not by 100) or year can be divisible by 400. Then this year is a leap year and this year is a normal year.

Calculation method of leap year

1, non-integer centenary: leap year is divisible by 4. (For example, 2004 is a leap year, and 200 1 is not. )

2, the whole hundred years: leap years can be divisible by 400. (For example, 2000 is a leap year, 1900 is not. )

3. For a year with a large number: If this year can be divisible by 3200 and 172800, it is a leap year. For example, 172800 is a leap year, and 86400 is not (because it can be divisible by 3200, but it cannot be divisible by 172800) (this is calculated on the basis of 365 days, a tropical year of 5h48'45.5'').

Calculation method of leap year in BC:

1, non-whole hundred years: the number of years is divided by 4, and the remainder 1 is a leap year, that is, 1, 5,9 ... BC is a leap year;

2. Whole hundred years: the number of years divided by 400 and the remainder is 1 are leap years, that is, 40 1 and 80 1 BC are leap years.

Extended data

Reasons for leap years

The period of the earth's orbit around the sun is 365 days, 5 hours, 48 minutes and 46 seconds (365.438+09 days), which is the tropic of cancer. The Gregorian calendar has an average of only 365 days a year, which is about 0.2422 days shorter than the tropical year, and the remaining time is about one day every four years. So 1 day is added at the end of February of the fourth year, making the calendar year of that year 366 days, and this year is a leap year.

The current Gregorian calendar has 97 leap years every 400 years. According to a leap year every four years, it will count as 0.0078 days per year on average, so after 400 years, it will count as 3 days. So every 400 years, three leap years will be reduced.

Sogou encyclopedia-leap year

Leap year algorithm

What a good spirit of inquiry! Hehe, let's talk about why: a year with leap days in the solar calendar is called a leap year, and vice versa, with 365 days in a normal year and 366 days in a leap year.

In the Gregorian calendar year, February in a normal year is 28 days, and February in a leap year is 29 days. February 29th of a flat month in a leap year is a leap day.

Reasons for increasing leap days The current Gregorian calendar is based on the tropical year, which is about 365.24220 days. Because the average calendar year is only 365 days, it will accumulate 0.24220*4=0.9688 days after four years, which is about equal to one day, so a leap day is added every four years to offset this 0.9688 days.

But it is still a little short, so there is not much time at present, but after one hundred years, there will be a difference of about 0.78 days, that is, more. Therefore, it is necessary to re-define the details until 100, which will reduce the time by 0.22 days every 100, and by 400 years, the difference is about 0.9 days, so basically only the days with embellishment will correspond to it in a hundred years.

But there are still some errors, but they are quite small. I just made a rough calculation, and the actual difference is very small.

The calculation method of leap year in Gregorian calendar chronology can be divided by 4 except those years that can be divided by 100 but not by 400. For example, 1900 is the normal year. Leap in four years, not in a hundred years, and leap in four hundred years. "

So your question is mainly caused by these insignificant decimals, but over time it can be a hundred years of "days". How's it going? See. You can push it yourself and see if it's right, hehe.

How to calculate leap year?

Calculation method of leap year in Gregorian calendar: 1. A leap year is a year in which ordinary years are divisible by 4 and cannot be divisible by 100.

(For example, 2004 is a leap year, 1900 is not. ) 2. Leap year is a century year divisible by 400. (For example, 2000 is a leap year and 1900 is not) 3. For years with large numbers, if 3200 is divisible and 172800 is divisible, it is a leap year.

The purpose of establishing extended data leap year is to make up for the time difference between the number of days in a year and the actual period of revolution of the earth caused by man-made calendar regulations. The year to make up for the time difference is leap year.

Leap year * * * has 366 days (February is 1- 1 day, 29 days, 3 1 day, 30 days, 3 1 day, 3 1 day respectively). Where there is a leap day (February 29th) in the solar calendar, the rest of the year is a leap day.

Time difference between lunar calendar and tropic year. References:

Baidu encyclopedia-leap year.

Calculation method of leap year in China lunar calendar

There is no leap day in the solar calendar and no leap month in the lunar calendar. There are 365 days in the solar calendar and 354 or 355 days in the lunar calendar.

Or a year when the crops are very common.

The number of years in AD can be divisible by 4 into leap years, but the number of years in Zhengbai must be divisible by 400. Everything else is a normal year. February in leap year has 29 days. For example, 1996 is a leap year, 2000 is a leap year, and February in a normal year has 28 days, 1900 is a normal year, and 1997 is a normal year.

A year with a leap month in the lunar calendar is called a leap year.

Leap year: 1. In order to make up for the time difference between the artificial year and the actual revolution of the earth around the sun, 2. The year in which man-made jet lag is compensated is leap year.

The following rules are: jump in four years, not jump in a hundred years, and jump again in four hundred years.

if((year % 400 = = 0)| |(year % 4 = = 0)& amp； & (year% 100! = 0)) Calculation method of leap year

What is the calculation method of flat year and leap year?

A, the average annual calculation method

1. leap year is a year in which ordinary years are divisible by 4 and cannot be divisible by 100. (For example, 2004 is a leap year, and 190 1 is not. )

2. Leap year can be divisible by 400 in century year. (For example, 2000 is a leap year, 1900 is not. )

Second, the leap year calculation method

1, non-integer centenary: leap year is divisible by 4. (For example, 2004 is a leap year, and 200 1 is not. )

2, the whole hundred years: leap years can be divisible by 400. (For example, 2000 is a leap year, 1900 is not. )

3. For a year with a large number: If this year can be divisible by 3200 and 172800, it is a leap year. For example, 172800 is a leap year, and 86400 is not (because it can be divisible by 3200, but it cannot be divisible by 172800) (this is calculated on the basis of 365 days, a tropical year of 5h48'45.5'').

Extended data:

First, the method of judging the average year.

1. To judge whether a year is a leap year, you only need to look at the last two digits of the year. If the last two digits are divisible by 4, it is a leap year, otherwise it is not.

2. When the last two digits are all 0, we will look at the first two digits of the year; If the first two digits are divisible by 4, it is a leap year, and vice versa.

3. If the two digits at the end of 2004 are 04, it can be directly regarded as 1 digit. If this number is divisible by 4, it is a leap year, otherwise it is not.

Second, the causes of leap years

The period of the earth's orbit around the sun is 365 days, 5 hours, 48 minutes and 46 seconds (365.438+09 days), which is the tropic of cancer. The Gregorian calendar has an average of only 365 days a year, which is about 0.2422 days shorter than the tropical year, and the remaining time is about one day every four years. So 1 day is added at the end of February of the fourth year, making the calendar year of that year 366 days, and this year is a leap year.

The current Gregorian calendar has 97 leap years every 400 years. According to a leap year every four years, it will count as 0.0078 days per year on average, so after 400 years, it will count as 3 days.

So every 400 years, three leap years will be reduced. Therefore, the Gregorian calendar stipulates that when the year is a whole hundred, it must be a multiple of 400 to be a leap year; It is not a century year with multiples of 400, and even a multiple of 4 is not a leap year.