Many older tombstones list age and date of death. The Tombstone Birthday Calculator calculates birthdate from the age of death and the date of death on the tombstone, death certificate or obituary. Results are given in a year-month-day format.
- Birthdate Calculator Tips for Usage
- Calculated dates should only be considered approximate due to possible errors or possible different methodology used in the original calculation (found on the tombstone, obituary or death certificate). Be sure to note in your records that your date was calculated.
- This calculator can use either the exact month method or the 30 day month method to compute a birthdate. While you may think the exact calendar month method may be more reliable, be aware that many of the headstone and obituary ages at death appear to have been computed using the 30-day-month method. (The 30-day-month method assumes that all months have 30 days. It’s an approximation which agrees with the exact calendar month method about 2/3 of the time.)
- A tombstone or death certificate is not considered a primary source for a birthday, but it can give you an approximate date of birth to help in further research.
- The calculator could also be used to calculate birth year from census data or birthdate from wedding date and age.