About 123AgeCalculator
123AgeCalculator is a free set of 17 age calculators: exact age, age in days, weeks, months and seconds, birthdays, age gaps, a baby's corrected age, retirement age, generations, Korean age, Chinese zodiac, and ages on other planets and for dogs and cats. There are no accounts, no ads and no tracking.
What we care about
- Exact answers. Ages are counted on the calendar — whole years, then whole months, then days — never by dividing by 365.25. Leap years, short months and 29 February birthdays are handled by one consistent rule, explained on how age is calculated.
- Showing the working. Every calculator has a worked example with real dates, the rules it follows, and the sources behind its tables — the U.S. Social Security Administration, Pew Research Center, NASA, veterinary guidelines and more.
- Fast and private. Pages load in a moment, work without JavaScript, and nothing you enter is stored. See the privacy policy.
- Easy to share. Every result has its own link and its own picture, so "I am 13,286 days old" looks like exactly that when you post it.
How the calculators are checked
Each calculator runs the same code whether you see the result on the page, as you type, or in a shared picture, so the three can never disagree. The worked examples on every page are calculated live from fixed dates, and an automated test suite checks the date arithmetic — including month ends and leap days — before every release.
Part of the 123 family
123AgeCalculator is made by the team behind 123Calculator.app (hundreds of free calculators) and 123SpinWheel.com (free spin-the-wheel pickers): simple, free web tools that do one job well.
Contact
Found a mistake, or want a calculator we don't have? Email hello@123agecalculator.com — corrections are fixed quickly.