Date & Time Tool

Age Calculator

Calculator

Calculate your age

Enter a date of birth and the date to measure it against — calculated entirely in your browser.

Type it, or open the calendar to pick the year first.

Enter a date of birth to see the exact age.

You’ll get years, months and days, the totals, and a countdown to the next birthday.

Tool features

Comprehensive age calculation with detailed breakdown in multiple time units
4 features

Precise Date Calculation

Exact age in calendar years, months, and days — leap years are handled automatically

Custom Date Comparison

Compare your age on any specific date, not just today

Multiple Time Units

Detailed breakdown including total months, weeks, days, hours, and minutes

Birthday Fun Facts

Birthday twins, star sign, milestone countdowns, life in numbers and your age on other planets

What is an age calculator & how it works

How exact calendar age is measured

An age calculator measures the exact time between a date of birth and a target date in calendar years, months and days — not by simply dividing days by 365. Because months differ in length and leap years add a day, the calculation borrows days and months like long subtraction on the calendar itself, so the result always matches how birthdays actually fall.

Beyond the headline age, this tool converts the same span into totals — months, weeks, days, hours and minutes — counts down to the next birthday, and adds fun facts such as birthday twins, zodiac signs, birthstones and the next 1,000-day milestone. Everything is calculated in your browser; no dates are sent to a server.

Chronological age
The time elapsed since birth, expressed in full calendar years, months and remaining days.
Leap year
A year with February 29 — an extra day roughly every four years that calendar-exact age math must account for.
Next birthday
The number of days until the birth month and day next occur on the calendar.

How to use this tool

Work out an exact age in four steps
1
Enter a date of birth
Type it straight into the field, or open the calendar — it starts on the year grid, so you pick the year, then the month, then the day.
2
Choose the "age at" date
It defaults to today. Pick any other date, or use the shortcuts: Today, End of this year, or Next birthday to see the age you are about to turn.
3
Read the result
The exact age in years, months and days appears instantly below the dates, plus totals in months, weeks, days, hours and minutes.
4
Review the extras
Check the next-birthday countdown and the fun facts, grouped into tabs: your birthday, upcoming milestones, life in numbers and your age on other planets.

Related tools

Keep debugging with tools from the same suite
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Frequently asked questions

Common questions about age calculation
5 Q&A

Age is measured in calendar units: full years first, then full months, then the remaining days. If the day of the month has not been reached yet, days are borrowed from the previous month — so different month lengths and leap years are respected exactly.

Yes. Calculations use real calendar dates, so February 29 and every leap year are handled automatically — both in the years/months/days result and in the day totals.

Yes. Set the "age at" date to any date after the date of birth — a date in the past, a deadline, or a future milestone. The Today shortcut sets it back to the current date, and Next birthday jumps straight to your upcoming birthday.

Your exact birthday only exists in leap years. In other years the next-birthday countdown rolls over to March 1 — the day after February 28.

Total days is the exact number of days between the two dates; weeks, hours and minutes are derived from it (÷7, ×24, ×1,440). Total months counts full calendar months elapsed.