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Age at Death Calculator
The two dates
Example: born March 15, 1948, died October 22, 2023 — 75 years, 7 months, 7 days (27,614 days).
Behind the numbers
How age at death is calculated
The calculator counts full calendar years first, then full months, then the remaining days, borrowing from the previous month when needed — the same way a calendar counts age. It uses real calendar months and leap years, not a fixed 30-day month, so February 29 and months with 31 days are handled correctly. The total days are counted directly from the two dates, and the weeks are the total days divided by 7.
Start with the birth date, March 15, 1948. From 1948 to 2023 is 75 full years, because the birthday (March 15) had already passed in 2023. From March 15 to October 15, 2023 is 7 full months, and from October 15 to October 22 is 7 more days: 75 years, 7 months, 7 days. Counting every day between the two dates gives 27,614 days, which is 3,944 weeks and 6 days, or 907 full months.
Examples
Example ages lived
| Date of birth | Date of death | Age lived | Total days |
|---|---|---|---|
| March 15, 1948 | October 22, 2023 | 75 years, 7 months, 7 days | 27,614 |
| January 1, 1950 | January 1, 2000 | 50 years, 0 months, 0 days | 18,262 |
| July 4, 1960 | July 4, 2020 | 60 years, 0 months, 0 days | 21,915 |
| February 29, 2000 | February 28, 2024 | 23 years, 11 months, 30 days | 8,765 |
| December 10, 1985 | May 3, 2021 | 35 years, 4 months, 23 days | 12,928 |
Tips
Use the exact dates from a birth certificate or death certificate for the most accurate result.
If only the years are known, the result can be off by up to almost a year — add the months and days when you can.
A person born on February 29 has a birthday on February 28 or March 1 in non-leap years; this calculator counts the age the same way a calendar does, day by day.
The total-days figure is useful for obituaries and family records, where a lifespan is often written as years, months, and days.
Good to know
Frequently asked questions
How do you calculate age at death?
Subtract the birth date from the death date using calendar years, months, and days. Count the full years first, then the full months after the last birthday, then the days left over. This calculator does that with real month lengths and leap years.
Why is the total in days different from years times 365?
Because leap years add extra days, and the two dates do not fall on the same day of the year. Counting every day between March 15, 1948 and October 22, 2023 gives 27,614 days.
What if the person was born on February 29?
The calculator still works: it counts days on the real calendar. For example, someone born February 29, 2000 who died February 28, 2024 lived 23 years, 11 months, and 30 days — one day short of their 24th birthday.
Does this calculator include the day of death?
It counts the days lived up to the date of death, not including an extra day for the death date itself. That matches how age is normally stated: a person who dies on their birthday has just completed that year of life.