Chronological age is how much time has passed since you were born, counted to a specific date. It's the everyday meaning of age. The term shows up most in medicine, psychology, and education, where the age has to be precise, usually years and months, or a single decimal.

It's the calendar span from the date of birth to the reference date: full years, then whole months, then the remaining days. So a child might be 7 years, 4 months, 16 days. The same age is often written as a decimal, 7.34 years, found by dividing the total days lived by 365.25 to allow for leap years.

• Paediatrics and child development, checking a child's growth or skills against the typical range for their exact age.
• Education, school-entry cut-offs and year-group placement often turn on age to the month.
• Research and assessment, many standardised tests are scored against precise chronological age.

Chronological age isn't the same as biological or developmental age, which estimate how old someone seems physically or developmentally. Chronological age is just the time since birth. If you want it in other units, see your age in days, weeks, and months, or check how old you are today.