How age is calculated
Your age in completed years goes up by one on each birthday. To get the exact age, count the full years since you were born, then the full months since your last birthday, then the days since the last "month birthday."
- Years: subtract the birth year from the current year. If this year's birthday hasn't happened yet, subtract one more.
- Months: count the full months since your last birthday.
- Days: count the days since the same day-of-month as your birthday last came around.
Worked example
Born 18 August 1996. What is the age on 5 March 2026?
Years: 2026 − 1996 = 30. But the 2026 birthday (18 August) hasn't come yet, so it's 29 years.
Months: from 18 August 2025 to 18 February 2026 is 6 months.
Days: from 18 February to 5 March 2026 is 15 days (February 2026 has 28 days).
Age: 29 years, 6 months, 15 days.
Leap years and February 29 birthdays
Months have different lengths, so "one month" isn't a fixed number of days. The calculator counts calendar months, which is how people and most official documents state age.
If you were born on 29 February, your birthday only appears on the calendar every four years. In other years, this calculator treats 28 February as your birthday. Legal rules differ by country: in some, a leap-day baby legally turns a year older on 1 March in non-leap years. Check local rules for official purposes like a driving licence.
A year is a leap year if it divides evenly by 4, except century years, which must also divide by 400. So 2000 was a leap year and 1900 was not.
Where an exact age matters
- Forms and applications: school admissions, exams and job applications often set an age limit on a specific cut-off date. Set "age on this date" to that cut-off.
- Retirement and pensions: find the date you'll reach a pension age, or how far away it is.
- Babies and toddlers: doctors track infant ages in weeks and months, which the totals above show.
- Fun facts: your 10,000th day alive comes at about 27 years and 4 months.
Age in different cultures
Most countries count age the "international" way used here: you're 0 at birth and gain a year on each birthday. Traditional East Asian age reckoning (still used informally in some places) counts a newborn as 1 and adds a year at the new year. South Korea switched official documents to the international system in 2023.
Frequently asked questions
Does the calculator use the time I was born?
No. It works with whole calendar days, which is how age is normally stated. Birth time could only move the result by one day.
Can I calculate the age of something other than a person?
Yes. Enter any start date, like when a company was founded or a pet's birthday, to get the time elapsed. For a plain count of days between two dates, try the date difference calculator.
Is my birthday saved anywhere?
No. The calculation happens on your device and nothing is stored or sent.
Last reviewed November 2026.