BASIC (09-87)

GN 00302.710 Age Information in Census Records

A. General

In most years the census taker asked individuals their age in terms of “age at last birthday” as of the Census Day. The person's age was written in whole years, except as noted in the last column of the table below. At no time has the exact day of birth ever been asked.

Except for the 1950 census (see “Note” in F. below), the census transcript shows complete years and months.

B. Example 1

The transcript shows “0/12 months.” This indicates that the child was not yet one month old on the Census Day for that year's enumeration.

C. Example 2

The transcript shows “1 3/12”, indicating that the child was one year and three months old on the Census Day.

D. Example 3

A child enumerated in the 1920 census who was born on 10/20/18 would be shown on the transcript as “1 2/12.”

E. Use judgment

Since the census was rarely taken on Census Day, the census transcripts may not always reflect accurate information as of the Census Day. Exercise judgement when evaluating a census transcript which shows the age in months.

F. Census Day for period 1900 - 1970

The following table shows the date of the Census Day for the period 1900 - 1970, and other data pertaining to each census.

YearCensus DayHow Age Was AskedAge Shown in (Years and) Months IF...
1900June 1age, month, and yearunder 1 year old
1910April 15age at last birthdayunder 2 years old
1920January 1age at last birthdayunder 5 years old
1930April 1age at last birthdayunder 5 years old
1940April 1age at last birthdayunder 1 year old
1950April 1age at last birthdayunder 1 year old (see note below)
1960April 1quarter of year in which birth occurred and year
1970April 1age, month, and year

NOTE:  In the 1950 census, the month of birth is shown for children who were less than 1 year old on April 1.