Adjusted Age Calculator

Premature babies have an adjusted age used for some milestones and other purposes, which is the amount of time since their due date. It can be calculated from the original due date, the mother's last menstrual period, or the baby's gestational age at birth.

There are plenty of calculators out there already, but I wanted one that saved the dates and gave both ages in various formats. Months are calendar months, so some ages may appear strange, as explained by this age calculator. Please note that babies born at or after 37 weeks are not considered premature, but this calculator will still adjust them.

You can also use the calculator to determine due date from the last period or vice versa.