Ever wondered exactly how old you are — not just in years, but in months, weeks, days, hours, and even seconds? Our Age Calculator gives you the full picture instantly. Simply enter your date of birth and choose a date to calculate your age on (today is filled in automatically), and we will do the rest.
Whether you need your exact age for a form, want to find out how many days until your next birthday, or are just curious about how many seconds you have been alive — this calculator has you covered.
Age Calculator
Enter your date of birth and the date you want to calculate your age on. The “Calculate Age On” field is set to today by default — you can change it to any date in the past or future.
How Is Age Calculated?
Age is calculated by finding the difference between your date of birth and the target date. The calculator counts whole completed years first, then the remaining months, and finally the remaining days. This mirrors the way age is officially recorded in most countries — you only “gain” a year on your actual birthday.
For example, if you were born on 15 March 1990 and today is 10 April 2026, you have completed 36 full years (your 36th birthday passed on 15 March 2026) plus 26 additional days.
What Else Does the Calculator Show?
What Is a Leap Year and Why Does It Matter?
A leap year has 366 days instead of the usual 365, with the extra day added as 29 February. A year is a leap year if it is divisible by 4 — except for century years (like 1900), which must be divisible by 400 (so 2000 was a leap year but 1900 was not). Leap years affect the total day count, which is why our calculator accounts for them precisely.
If your birthday is 29 February, you only have a “true” birthday every four years. In non-leap years, birthdays are conventionally celebrated on 28 February or 1 March depending on the country.
How Is Age Calculated Differently Around the World?
Frequently Asked Questions
Can I calculate my age on a future date?
Yes. Simply change the “Calculate Age On” date to any future date and the calculator will tell you exactly how old you will be on that day. This is useful for planning milestones like retirement or significant birthdays.
Can I calculate someone else’s age?
Absolutely. Enter any person’s date of birth in the first field. The calculator works for any birth date, whether that is a newborn baby or a centenarian.
Why might my age in days differ from other calculators?
Small differences between calculators are usually due to how leap years are handled, or whether the birth date itself is counted as day zero or day one. Our calculator uses the standard method where the birth date counts as day zero.
How accurate are the hours, minutes, and seconds?
These figures are calculated from the total number of complete days (multiplied by 24, 1,440, and 86,400 respectively). They do not account for the exact time of birth, so they are an approximation based on whole days only.