Date & Time

Age Calculator

Choose a birth date to see exact calendar age immediately. Use another reference date only when you need age on a past or future date.

Start here

Date of birth

Your age appears as soon as you choose a birth date.

Use another reference date Today

Calculate age on

Exact ageEnter your date of birth

We will use today unless you choose another date.

—Total days

—Completed weeks

—Completed months

Next birthday—

——

Core timing workflows

Start with a direct timer, stopwatch, alarm or focus workflow. Calendar, date arithmetic, clocks and scheduling specialists remain available from the full Date & Time hub.

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How to use the Age Calculator

Choose your date of birth. Your exact age appears immediately using today as the reference date. Open “Use another reference date” only when you need age on a past or future date.

What the result means

The main answer uses calendar years, months, and days rather than a decimal-year approximation. Total days, weeks, completed months, and next-birthday timing are shown as supporting context.

Calendar note

Month lengths and leap years are handled with Gregorian calendar arithmetic. Legal age rules can vary by jurisdiction, especially around leap-day birthdays, so this is a date calculator rather than a legal determination.

Calendar age, not a decimal-year estimate

Exact age is counted in calendar years, then months, then days against the selected reference date. This preserves real month lengths and leap years instead of dividing elapsed days by an average year length.

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