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California Genealogy and History Archives

Period Approximation Chart

 

Date Wanted Known Information Formula
Birth Age at dated event  Subtract age from date 
Add 5 years to each side 
Search 11 year period 
Birth Marriage date Subtract 16 years from date 
Subtract 40 years from date 
Search period between dates 
Birth Birth or christening of child: Female - only child  Subtract 16 years from date 
Subtract 50 years from date 
Search period between dates 
Birth Female - several children Subtract 16 years from date of first child 
Subtract 50 years from date of last child 
Search period between dates 
Birth Male - only child Subtract 16 years from date 
Subtract 70 years from date 
Search period between dates 
Birth Male - several children Subtract 16 years from date of first child
Subtract 70 years from date of last child 
Search period between dates 
Marriage Age at dated event Calculate age 15 Add 25 years to date 
Search period between dates 
Marriage Birth or christening of child: only child  Subtract 34 years from date 
Add 1 year to date 
Search period between dates 
Marriage Several children Subtract 34 years from date of last child Add 1 year to date of first child Search period between dates