Child & Adult Age Calculator

Enter the child’s date of birth and today’s date (or any as-of date) and the calculator returns the child’s exact age in years, months and days, plus total days and weeks. For a young child you can read the age in months, and for a baby in weeks. A child born on 1 September 2019, as of 24 June 2026, is 6 years, 9 months and 23 days old. The same calendar-aware method works for a child, a teenager or an adult — it never approximates with divide-by-365.

Divide the total number of days lived by seven and take the whole number. A baby born on 1 April 2026, as of 24 June 2026, is 84 days old — that is exactly 12 weeks (about 2 months and 23 days). New parents usually track age in weeks up to a few months, then in months, which is why the baby-age mode reads the age in weeks and months rather than years.

Corrected age adjusts a preterm infant’s age for prematurity: chronological age − (40 weeks − gestational age at birth). A baby born at 32 weeks is 8 weeks early, so its corrected age is 8 weeks less than its chronological age. Paediatric milestone and growth tracking use corrected age until about 24 months, after which the adjustment is no longer applied.

Yes. Set the "age at date" field to any date — past or future — and the tool reports the exact age as of that date. This is useful for eligibility cut-offs, school-entry dates, forms and "how old will I be on…" questions. The birth date and the as-of date can be in either order; the result is always order-normalized to a positive age.

In non-leap years there is no 29 February, so we treat the birthday as falling on 1 March — the common legal convention in most of the world. This is stated explicitly rather than left to chance; some date libraries instead clamp to 28 February, but we pick 1 March as the default.

In the traditional East-Asian reckoning you are considered 1 year old at birth and gain a year at each New Year, so your East-Asian age is usually 1–2 years higher than your international age. The tool defaults to the international system and offers East-Asian as an explicit option — it never applies it silently.

No. All calculations run on UTC midnights, so a day is always a full calendar day regardless of a 23-hour or 25-hour local clock change during a daylight-saving transition. Anchoring to UTC avoids the off-by-one errors that arise when date math is done in local time across a DST boundary.