Cemetery Directory USA
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Tombstone Birth Date and Age Calculator

Many 18th and 19th century gravestones give only a date of death and an exact age, such as "Aged 65 yrs, 4 mos, 12 ds". Enter both to work out the date of birth, or enter two dates to get the exact age at death.

What do you want to work out?

Example values are filled in. Gravestones often read "Aged 65 yrs, 4 mos, 12 ds"; enter those three numbers as they appear.

Calculated date of birth
Friday, November 2, 1821

Died Monday, March 14, 1887, aged 65 years, 4 months and 12 days. Carvers and families did not always count the same way, so check the result against a birth, baptism or census record and allow a day or two either side.

How the birth date is calculated

The calculator starts from the date of death and steps back the number of years, then the number of months, then the number of days on the calendar. This is the method most genealogists use, and it matches how ages were usually counted on stones: completed years, then completed months, then the remaining days.

For example, a person who died on March 14, 1887, aged 65 years, 4 months and 12 days, steps back to March 14, 1822, then to November 14, 1821, and then 12 days to November 2, 1821.

Reading the age on a weathered stone

  • Look for the abbreviations "y", "yrs", "m", "mos", "d" and "ds". Some stones write "Ae" or "AEt" (from the Latin aetatis, "of age") before the age.
  • Photograph the stone with low, raking light from one side rather than applying chalk or shaving cream, which damage the surface.
  • If a digit is unclear, try each possibility and see which result agrees with census ages or a baptism date.

For the full research process, see How to Find an Old Grave and How Do You Find Where Someone Is Buried?. To read the carvings themselves, see Gravestone Symbols and Their Meanings. Old family and church burial grounds are listed under historic cemeteries.

Updated November 7, 2026 · Built and reviewed by the Cemetery Directory USA editors.This tool runs in your browser; nothing you enter is sent to us or stored.

Frequently asked questions

Why do old gravestones give age instead of a birth date?

Recording the exact age in years, months and days was a common custom in the 18th and 19th centuries, especially in New England and among German communities. It also left more room on a small stone than two full dates.

Why is my result a day off from a birth record?

Families and carvers did not always count the same way. Some counted the day of death, some did not, and ages were sometimes taken from memory or a family Bible. Treat the calculated date as a strong lead, and allow a day or two either side.

Does this work for dates before 1752?

The arithmetic works, but the British colonies used the Julian calendar until September 1752, when 11 days were dropped and the new year moved from March 25 to January 1. For earlier dates, note which calendar the stone or record used before comparing results.

What is the 8870 method?

A pencil shortcut genealogists use: write the death date as YYYYMMDD, subtract the age written as YYMMDD, then correct an impossible result by subtracting 8800 if the month is impossible, 70 if the day is impossible, or 8870 if both are. Because it assumes 30-day months it can be a day or two off; this calculator does the calendar arithmetic directly.