Age Calculator
Enter a date of birth to calculate the exact age in years, months, and days — plus hours and minutes lived, and a countdown to the next birthday.
Age
Years
Total Months
Total Days
Total Hours
Next Birthday
Days away
Years old
Date
How Age Is Calculated
The calculator computes age the way it is conventionally counted in most Western countries — based on the number of complete years, months, and days that have elapsed since the date of birth.
A year increments on the birthday itself. If you were born on March 15, you turn 30 on March 15 — not on March 14 or 16. This is "birthday-based" age calculation, as opposed to the Korean age system, which adds one year at New Year rather than on the individual's birthday.
The total days figure is a straight count of calendar days elapsed between the two dates, including leap days.
Leap Year Birthdays
People born on February 29 have a birthday that only appears on the calendar every four years. For the purposes of this calculator, the birthday is counted on March 1 in non-leap years (the convention in most countries, including for legal purposes in the United States and United Kingdom).
Age in Different Cultures
How age is counted varies by country:
Western counting — Age starts at 0 at birth and increments each birthday. A newborn is 0 years old. This is the method used by this calculator.
East Asian (traditional) counting — A person is considered 1 year old at birth and gains a year each Lunar New Year. This system is less commonly used in official contexts today.
Korean age — Similar to traditional East Asian counting. A Korean age is typically 1–2 years higher than a Western age. South Korea officially standardised to Western counting in 2023.
Frequently Asked Questions
Why does the age in months not match exactly?
Calendar months have different lengths (28, 29, 30, or 31 days), so "months old" is always an approximation when expressed as a round number. This calculator counts the number of complete calendar months since birth, which matches how age is conventionally stated.
What does "age as of" mean?
By default, the calculator uses today's date. You can change the "Age as of" field to calculate how old someone will be on a future date (e.g. their age at retirement) or how old someone was on a past date (e.g. at a historical event).
Can I calculate age for dates before 1900?
Yes. The calculator supports any valid calendar dates. Historical ages for ancestors, historical figures, or genealogical research are all supported.
How many days old am I?
Enter your date of birth and click Calculate — the total days figure is shown in the stats grid. Most adults are between 10,000 and 30,000 days old.
What is the "10,000 days" milestone?
10,000 days is roughly 27 years and 4 months. It's a popular personal milestone — some people celebrate it as a notable landmark. You'll be able to see exactly when you hit it using this calculator.
