Age Calculator: A Step-by-Step Guide

Age Calculator takes two dates — a birth date and a reference date — and works out the exact difference between them in years, months, weeks, days, hours, minutes, and seconds.

Step-by-step

1. Enter the date of birth.
2. Set the reference date — defaults to today, but you can change it to calculate age as of any date.
3. Calculate to see the full breakdown.

Not just for birthdays

Because the reference date is adjustable, this works for any date-difference question, not just "how old am I today": how old someone was on a specific historical date, how much time is left until a deadline, or the exact duration between two events.

What's included in the breakdown

Along with the exact age, the tool detects your zodiac sign (Western tropical astrology, based on birth month and day) and tells you whether your birth year was a leap year — both computed directly from the date you enter, not looked up externally.

Troubleshooting

• "The age seems off by a day." Double check the reference date — if it's not set to today, the result reflects age as of whatever date you entered.
• "I want age between two arbitrary dates, not up to today." Set the reference date field to whatever end date you need — it doesn't have to be today.

Ready to calculate? Open the free Age Calculator.