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
Death   Calculate birth date
Add 90 years
Search period between date last known alive and 90th year


Adapted from "Basic Course in Genealogy," Vol.II, by Derek Harland



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