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Age Calculator

Calculate exact age in years, months, and days between any two dates. Also outputs total weeks, days, hours, minutes, and the next birthday countdown.

  • Runs in browser
  • No signup
  • No tracking
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How to use Age Calculator

  1. Pick a birth date (or start date).

  2. Pick a target date — defaults to today.

  3. Read your age in years/months/days plus totals.

  4. Switch the target date to plan birthdays or anniversaries.

When to use it

  • Birthday and anniversary planning.

  • HR systems verifying age eligibility.

  • Calculating duration between two project milestones.

  • Fun stats — minutes alive, weeks until next birthday.

What it fixes

  • Off-by-one errors when birthdays haven't happened yet this year.

  • Counting whole months across leap years.

  • Mental math for milestone birthdays.

About Age Calculator

An age calculator answers a simple question with surprising nuance: how old is someone, exactly? Naive subtraction (today − birthday) ignores months and days, so a person whose birthday is tomorrow gets aged up by a full year.

This tool walks the calendar properly: full years between the dates, then full months, then leftover days. It also reports total days, hours, and minutes — useful for milestones (10,000 days alive, 1 million minutes) and for measuring durations between any two dates, not just birthdays.

References: MDN — Date object

Frequently asked

  • How is age computed?

    We compute calendar-aware years, then months, then days — the way humans count birthdays. We also report total days, hours, and minutes, which are unambiguous.

  • Why does my count differ from another calculator?

    Some calculators ignore the day-of-month and only count whole years. We respect the day — so if your birthday is tomorrow, you're not 30 yet.

  • Is my date private?

    Yes. The calculation runs entirely in your browser via the JavaScript Date object. Nothing is sent to a server.

Discussion

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