Age Calculator
Calculate exact age in years, months and days from a date of birth, plus total days lived and days until the next birthday.
How exact age is calculated
Age is counted in completed calendar units. First count the full years since birth, then the full months since the last birthday, then the remaining days. When the day of the month has not been reached yet, one month is borrowed and the days of the previous month are added.
Someone born on June 15, 1990 is, on March 10, 2025, 34 years, 8 months and 23 days old. Their last birthday was June 15, 2024; eight full months bring us to February 15, 2025, and 23 more days reach March 10.
Leap-year birthdays
People born on February 29 have a calendar birthday only once every four years. In common years, many countries legally treat March 1 as the birthday for age-related purposes, while others use February 28. This calculator moves to the last day of February when the date does not exist.
Uses for an exact age
- Checking eligibility for school entry, sports age groups, retirement or pension rules.
- Insurance and medical forms that ask for age in years and months.
- Baby milestones, which are usually tracked in weeks and months.
- Fun facts: you pass 10,000 days old at around 27 years and 4 months.
Age in other cultures
Traditional East Asian age reckoning counts a newborn as one year old and adds a year at the new year rather than on the birthday. South Korea officially switched to the international system for legal purposes in 2023. This calculator uses the international method.
Frequently asked questions
How do I calculate my exact age?
Enter your date of birth and the calculator counts full years, then full months, then remaining days up to today or any date you choose.
How many days old am I?
The calculator shows total days lived. It also converts that into weeks, months and approximate hours.
Can I calculate age on a past or future date?
Yes. Change the "Age at the date of" field to any date.
Last reviewed Oct 20, 2026. Results are estimates; check important decisions with a qualified professional.