Age Calculator
The Age Calculator finds your exact age from your date of birth, broken down into years, months, and days, plus total days and hours lived. Useful for forms that require exact age, pediatric growth tracking, or just satisfying curiosity about how many days you have been alive.
How Age Is Calculated
The calculator subtracts the date of birth from today. For the years-months-days breakdown, it handles month boundaries correctly: for example, someone born on March 15, 2000 is exactly 25 years, 6 months, 15 days old on September 30, 2025 - not just a decimal number of years.
Age in Different Units
Your age in years is the most commonly used unit, but for babies, pediatric milestones are often tracked in months and days. For scientific or genealogical research, total days or total hours is sometimes needed. The calculator provides all four units simultaneously.
Legal and Medical Age Definitions
In most jurisdictions, you turn an age (18, 21, 65, etc.) at midnight on your birthday. Some legal contexts use the "last birthday" rule where you remain a particular age until the full year passes. Medical definitions, particularly for pediatrics, often use decimal age (e.g., 2.5 years means exactly 30 months old).
Frequently Asked Questions
How accurate is this calculator?
The calculator uses standard JavaScript math, which is accurate to approximately 15 significant decimal digits.
Is this calculator free?
Yes, completely free with no signup required.
Does it save my inputs?
Values are kept during your session but are not saved between visits. You can bookmark a URL with specific parameters to return to.
Can I use this on mobile?
Yes, the calculator is fully responsive and works on phones, tablets, and desktop browsers.
Does the result include weekends?
Depends on the calculator. Date calculators show both calendar days (including weekends) and business days (excluding weekends).
How is this different from Google calculator?
This calculator shows the step-by-step formula and provides specialized features (business days, mixed fractions, percent change) that Google calculator does not.
Can I share my calculation?
Copy the URL from the browser bar to share the current calculation state.
Where can I find more calculators?
See our complete list at /calculator.