Age in months calculator
Total months is complete years times twelve plus the leftover months. A child born on 15 June 2024 is 26 months old on 23 August 2026 — two years and two months.
How to find an age in months
Months are the standard unit for the first two or three years because development moves fast enough that years are too coarse. Health visitors, vaccination schedules and developmental checks all work in months, and clothing sizes are labelled that way for the same reason. After about three years the convention shifts to years, at which point stating an age in months starts to sound odd. The awkwardness of the unit is that a month is not a fixed length, so a child born late in the month reaches each month-mark after a different number of days than one born on the 15th. A baby born on 31 January is one month old on 28 February. After 28 days. A baby born on 31 July is one month old on 31 August, after 31. Nothing is wrong with either; a calendar month is defined by the day number coming round, not by a quantity of days, and the day count row is there for when you want the unambiguous figure instead.
Questions
Complete years times twelve plus the leftover months — the figure at the top.
Because development changes quickly enough that years are too coarse a unit.
No, whole calendar months are used, which is why the answer can differ from days divided by 30.
No, and it is a common mix-up. Twelve weeks is 84 days; three calendar months is 89 to 92, so they sit five to eight days apart.
The month-mark clamps to the last day of a shorter month. Born on 31 January, they are one month old on 28 February.
Usually around three, when growth slows and months stop being informative.
Use corrected age for developmental milestones: chronological months for vaccinations.