Age Calculator
Calculate your precise age from date of birth with full calendar accuracy. Compute age as of today or on any custom target date.
Online Age Calculator
Enter your date of birth (and optional birth time) to calculate your exact age in years, months, days, and live running seconds.
Synced with your local system clock
Every second represents 1,000 milliseconds since January 15, 2000.
Life Stats & Cosmic Ages
Comprehensive Time Breakdown
Help friends and family calculate their exact age & milestone countdowns
Understanding Accurate Age Calculation
When answering the question "How old am I?", most people state only their completed years. However, in legal, medical, educational, and international contexts (such as visa applications, school admissions, and clinical trials), exact age in years, months, and days is required.
Key Factors in Precision Date Math
- Varying Month Lengths: Months have 28, 29, 30, or 31 days. Subtraction requires borrowing from the exact preceding month.
- Leap Years: A Gregorian leap year contains 366 days instead of 365, occurring every 4 years (unless the century year is not divisible by 400).
- Timezone Independence: Calculations are date-only calendar values to avoid daylight savings shifts.
Help friends and family calculate their exact age & milestone countdowns
Frequently Asked Questions
Find clear answers to common questions about age calculation, leap years, and date math.