Age Calculator

Work out exact age down to the second, count down to a birthday, or compare two dates.

Date of birth
/ /
Calculate as of

About this age calculator

This tool works out the exact time between two dates — typically a date of birth and today — down to the year, month, day, and even the second. All the maths happens directly in your browser using your device's clock, so nothing you enter is ever uploaded or stored anywhere.

Calculate an exact age

Enter a date of birth to see age broken down into years, months and days, the weekday you were born on, and a live countdown to your next birthday.

See total time lived

Beyond years and months, view the same lifespan counted out in total days, weeks, hours, minutes and seconds — updating live if you're checking against today's date.

Compare any two dates

Switch to the "Compare two dates" tab to find the exact difference between any pair of dates — handy for anniversaries, deadlines, contracts or project timelines.

Tips for using this tool

  • Use the calendar icon next to any date field to pick a date visually instead of typing it.
  • Under "Calculate as of", switch from "Today" to "Another date" to calculate age as of a specific day in the past or future.
  • Use the milestone countdown to find out exactly how long until you (or someone else) turns 18, 21, 30, or any custom age.
  • The "Compare two dates" tab works both ways — it doesn't matter which date you enter first.

Frequently asked questions

How is age calculated exactly?

The tool takes the calendar difference between the date of birth and the reference date, counting full years, then full remaining months, then remaining days — the same way age is normally described in everyday speech.

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

Yes. Under "Calculate as of", select "Another date" instead of "Today" and enter any date you like — useful for checking eligibility ages or milestones on a specific day.

Why do the total days, hours and minutes keep changing?

When the reference date is set to "Today", the total time lived counters update live in real time. Switching to a custom reference date freezes them at that point.

Is my date of birth stored or sent anywhere?

No. Every calculation runs locally in your browser. Nothing you enter is transmitted to a server or saved after you leave the page.

How does the tool handle leap years and February 29 birthdays?

Calendar-based month lengths and leap years are handled automatically. For someone born on February 29, the next-birthday countdown lands on March 1 in non-leap years.