What are the calculation methods of one year old and nominal age?

One year old, according to the date of birth. For example, a person was born in May 2000 1, then he was 0 years old when he was born, 1 year old one year later, and so on. By May of 20 1 1 year, he will be 1 1 year old.

Nominal age, born 1 year, Spring Festival every year 1 year. According to the lunar calendar.

For example, a person's 30 th birthday in the twelfth lunar month 1 year old, and the first day of the first month of the next day, although only born for 2 days, is also considered 2 (imaginary) years old. And the birthday on the first day of the first month, until the first day of next month, that is, 1 year old, is only 2 years old.

Calculation method

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.