How is age calculated exactly?

Age is calculated by finding the difference between the birth date and today (or a target date). Years are counted by complete calendar years elapsed. Remaining months and days are counted after subtracting full years.

How many days have I lived?

The total days lived equals the difference in milliseconds between your birth date and today, divided by 86,400,000 (milliseconds per day), rounded down.

🎂 Age Calculator

Find your exact age in years, months, days, hours, and minutes. Also shows how many days until your next birthday — or age on any custom target date.

Years · Months · Days Next Birthday Any Target Date

Date of Birth

Age at date (default: today)

FAQ

How is the exact age calculated?

The tool subtracts full calendar years first, then counts remaining months, then remaining days. This matches how age is conventionally stated — for example, someone born on March 15 is not yet 30 until March 15 of their 30th year.

Can I calculate my age on a past or future date?

Yes — set the "Age at date" field to any date. Leave it blank to use today's date. This is useful for calculating how old you'll be at a future event, or how old you were at a past event.

How many days are in a year for this calculation?

The tool uses actual calendar days, accounting for leap years. It does not assume a fixed 365.25 days per year — it counts the real dates between your birth and the target date.

Does this tool store my birthday?

No. All calculation happens locally in your browser. Your date of birth is never sent to any server and is not stored anywhere.