WiseCalcs

Age Calculator

Enter your date of birth. The calculator instantly shows your exact age in years, months, and days, plus the total number of days you have been alive.

Use it to find your precise age in calendar units — years, remaining months, and remaining days — along with the total days elapsed since birth.

Enter your date of birth to calculate your age.

The result updates as soon as you enter a date. Years are whole completed years, months are the remaining complete months after the years, and days are the leftover days.

How does it work?

Years, months, and days are counted using calendar arithmetic, not fixed-length months. The total days figure counts the exact number of elapsed days.

Age calculation

Age=⌊today−birth date⌋\text{Age} = \lfloor \text{today} - \text{birth date} \rfloor
\text{today}
Today's date.
\text{birth date}
The date of birth.

Someone born on 1990-03-15 is 35 years, 2 months, and 23 days old on 2025-06-07.

Method & sources

Today's date is taken from your device's local clock at page load. Calendar arithmetic is used: a month is counted as complete once the same day-of-month has passed. Leap years are handled correctly: February 29 birthdays advance to March 1 on non-leap years when counting months and days.

Sources

Where this method comes from — use these references to understand the formula, assumptions, and limits.

How we calculate

  • Today's date is taken from your device's local clock at page load.
  • Calendar arithmetic is used: a month is counted as complete once the same day-of-month has passed.
  • Leap years are handled correctly: February 29 birthdays advance to March 1 on non-leap years when counting months and days.
  • The calculation uses UTC midnight for both dates to avoid time-zone edge cases.
  • Only dates of birth in the past are accepted.

Rounding

Years, months, and days are whole numbers derived from calendar arithmetic. The total days figure is the exact integer count of elapsed days.

What the calculator does

It counts from your date of birth to today using calendar arithmetic — not fixed-length months. It breaks the total span into years, remaining months, and remaining days, and also shows the total number of elapsed days.

How to use it

  1. Enter your date of birth in the date field.
  2. Read your exact age in years, months, and days on the right.
  3. Check the total days figure for a single number spanning your whole life.
  4. Use the share button to copy a link that reopens the same date.

An example

Someone born on March 15, 1990, is 35 years, 2 months, and 23 days old on June 7, 2025. The total is 12,868 days. The months and days always add up to less than a full year.

When it is useful

Useful any time you need a precise age — filling out a form, calculating an eligibility date, settling a birthday debate, or simply satisfying curiosity.

FAQ

How is age calculated?
The calculator subtracts your birth date from today using calendar arithmetic. It counts whole completed years first, then remaining complete months, then leftover days.
What if I was born on February 29?
In non-leap years, the calculator counts from March 1 for the months-and-days portion, as February 29 does not exist in those years.
Does it use my local time zone?
Both dates are treated as UTC midnight to avoid edge cases where the date could differ by one day depending on time zone.
Can I calculate the age of someone else?
Yes — just enter their date of birth. The calculator does not store or share anything.
Can I share a calculation?
Yes. Use the share button to copy a link that opens the calculator with the same date of birth pre-filled.

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Embed this calculator

Add this calculator to your own site. The snippet includes the calculator iframe and a small attribution link:

<iframe src="https://wisecalcs.com/embed/en/age-calculator" width="100%" height="520" style="border:0" loading="lazy"></iframe> <p>Calculator from <a href="https://wisecalcs.com/en/health/age-calculator">WiseCalcs</a></p>