Age from Date of Birth
All calculations should be independently verified prior to clinical use. These calculators are intended to supplement, not replace, clinical judgment.
Calculate age in years, months, weeks, and days based on date of birth and a reference date (defaults to today).
The reference date defaults to today and can be changed to calculate age at any past or future date — for example, a scheduled procedure date or a corrected gestational age milestone.
Months are calculated using an average month length of 30.4375 days (365.25 / 12). Weeks and days are exact. The year remainder (months) reflects the fractional year after subtracting whole completed years.