1. One year old

Also known as full age, it refers to the number of anniversaries or birthdays from birth to counting. For example, the census was conducted at 0: 00 on July 1990, and the baby was born in February 1989, with a nominal age of 2 years. Actually, it's just been more than six months, and I haven't celebrated my birthday yet. According to one year old, it should be less than 1 year old. One-year-old age is often 1 ~ 2 years younger than the nominal age, which is a commonly used age calculation method in population statistics.

2. Nominal age

According to the calendar year after birth, the commonly used age calculation method is 1 year even after birth, and it increases 1 year every New Year. Generally calculated according to the lunar calendar, but also calculated according to the Gregorian calendar. For example, a baby born at the end of 65438+February is 1 year after birth, or 1 year after the Gregorian calendar or the local Chinese New Year. In this way, the baby is only a few days old and is already 2 years old. This calculation method is practical.

People born in 1972 were born in 1983. I am 26 years old.

Extended data:

With the extension of the average life expectancy of the global population and the intensification of aging, WHO has redefined the age stage, stipulating that young people are under 44 years old, middle-aged people are 45-59 years old (prime of life), young people are 60-74 years old, real old people are 75-89 years old, long-lived people are over 90 years old, and centenarians are over 0/00 years old.

Exact age

Refers to the days from the date of birth to the date of calculation. It reflects people's real life time more accurately than one-year-old age, but it is rarely used for demographic statistics because of its complicated statistical summary. In real life, except for babies under 1 year, especially newborns under 1 month, people usually don't calculate the exact age by day.

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