What Is Chronological Age?
Chronological age is the amount of time that has passed since a person's birth, usually expressed in completed years, and sometimes in years, months, and days. It is calculated from the date of birth to a given date, taking month lengths and leap years into account.
How It Is Calculated
Subtract the birth date from the target date; if the target month and day come before the birth month and day, one year has not yet been completed.
Other Uses
Chronological age is distinct from measures such as gestational age or biological age estimates.
🧮 Calculate It Yourself
Put Chronological Age into practice with these free calculators — no sign-up, nothing stored.
🔗 Related Terms
More Time & Dates Terms
- 24-Hour Clock (Military Time)
- Business Days
- Calendar Quarter
- Coordinated Universal Time (UTC)
- Daylight Saving Time (DST)
- Equinox
📖 Browse all glossary terms or explore all free calculators.
Last updated: September 27, 2026. This definition is for general educational purposes only. It is not financial, investment, tax, legal, or medical advice, and it does not recommend any product or course of action. For decisions about your own situation, consult a qualified professional.