How Old Was He When He Died? Age at Death Calculator

Try an example

• Michael Jackson (August 29, 1958 to June 25, 2009): 50 years, 9 months and 27 days. His life on a timeline.
• Elvis Presley (January 8, 1935 to August 16, 1977): 42 years, 7 months and 8 days. His life on a timeline.
• George Washington (February 22, 1732 to December 14, 1799): 67 years, 9 months and 22 days. His life on a timeline.
• Julius Caesar (July 12, 100 BC to March 15, 44 BC, read as Julian dates): 55 years, 8 months and 3 days. His life on a timeline.

How the age at death is worked out

An age is counted in completed years: the number of birthdays the person lived to see. The calculator counts whole years from the date of birth, then whole months, then the days left over, so Michael Jackson, who died two months before his 51st birthday, was 50 years, 9 months and 27 days old.

A month on from the 31st lands on the last day of a shorter month, so January 31 plus one month is February 28, or February 29 in a leap year. Someone born on February 29 is counted a year older on February 28 in a common year. Some laws count that birthday on March 1 instead, which changes the years only for a death on February 28 of a common year.

The total in days is exact: the calculator turns each date into a day count (the Julian Day Number astronomers use) and subtracts.

Why subtracting the years can be off by one

The quick way to work out how old someone was when they died is to subtract the year of birth from the year of death. That gives the right age only if they had already had their birthday that year. Michael Jackson died in 2009 and was born in 1958, which is 51 years apart, but his birthday was in August and he died in June, so he was 50. Elvis Presley died seven months after his birthday, so for him the quick answer of 42 is right.

For dates BC the quick way goes wrong again, because there is no year zero: 1 BC is followed directly by AD 1. Someone born in 10 BC who died in AD 10 lived 19 years, not 20. The calculator handles both.

How old would they be today?

The calculator also says how old the person would be if they were still alive, counting their birthdays up to today, and how long ago they died. Elvis Presley would be 91 today. For someone born before 1582 that counts birthdays in today's Gregorian calendar, so Julius Caesar's birthday, read as a Julian date, falls on July 10 rather than July 12.

Old Style dates and the Julian calendar

The calendar most of the world uses, the Gregorian calendar, began on October 15, 1582. Before that, dates were written in the Julian calendar, so the calculator reads any date before October 15, 1582 as a Julian date. When someone was born before the change and died after it, their birth date is first rewritten in the Gregorian calendar so that their birthdays are counted in one calendar.

Britain and its American colonies kept the Julian calendar until 1752, and until then their year began on March 25. George Washington was born on February 11, 1731 by the calendar of the day, which is February 22, 1732 in the calendar we use now. Give the calculator the modern date, as most biographies do, and the age comes out right.

Ages on gravestones and in records

Many older gravestones and death records give the age at death in years, months and days, such as "aged 72 years, 3 months and 14 days", in the same order this calculator uses. If a record gives a date of birth and a date of death, the calculator shows whether they agree with the age carved on the stone. Records were often kept by people working the sums by hand, so a difference of a day or two is common.

Related tools

To count how many years ago someone was born, BC or AD, use the BC/AD years calculator. To find the weekday someone was born on in more detail, including Julian dates, use the day of the week calculator. To see which generation a birth year belongs to, use the generation calculator.

Putting a life in order

A birth and a death are the two ends of a life story. If you are researching a person or a family, Preceden can lay the events in between on a timeline, so you can see how old everyone was when each thing happened.