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Reverse Birthday Calculator

This converter requires the use of Javascript enabled and capable browsers. This script attempts to calculate the unknown birth date of some one that has died, based on the date of birth and the age at passing. Obviously, there is a wide margin for error as often those exact figures are not know but can usually be approximated. Good sources of information are often tombstones, newspaper clippings, family records or a family Bible. If you are using this to document any important papers or to prepare genealogy information, we suggest that you note in your records that the date was calculated by THIS calculator. It has been certified for use in many states and by many insurance organizations. The date calculation method is correct IF the information entered is correct. This calculator can use either the exact month method or the approximate 30 day month method to compute a birth date. One is inherently more accurate than the other but either is usually accurate enough for most purposes.

The calculator allows Julian calendar dates or Gregorian calendar dates; we suggest the use of the Gregorian calendar for the greatest accuracy within fairly modern times and the Julian calendar for times dating back 5 centuries and longer; however, you must be consistent within the same calculation. For more information on the differences, we suggest you go to our Julian Day and Date Time Calculator. The probability is low that you would need to do a calculation spanning the "crossover" time period but use the Julian calendar if you do have such a need. Enter numeric information as indicated in the fields. The indication of "nn" means a number up to 2 digits and "nnn" means up to three digits; "nnnn" is a mandatory 4 digit entry. You MUST enter at least one digit even if it is a zero (0). Based on that, your entries will be all digits or selections from the drop down boxes. Please pay close attention the number of "n" indicators. Since it could be ambiguous, the year of death MUST be 4 digits; while the age at death can be up to 3 digits. Click on calculate after the entries are made. You may print the page if desired by clicking on the Print button below the calculator.

Required Data Entry
Calendar Choice
Month Choice
Date Of Death
Day - nn
Year - nnnn
Age At Death
Day - nn
Month - nn
Year - nnn

Calculated Date Of Birth
Updated 8.15.11

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