Usratak

Baby age calculator

Enter your baby's date of birth to see the age in months, weeks and days, and the date of the next month mark.

By the Usratak editorial team·Last updated: 26 October 2026·Sources

Baby's date of birth
Age at date
Age at date

Enter the date of birth to see your baby's age.

How age is counted

The calculator counts whole calendar months from the date of birth, then the days left over. This is how most parents and pediatric clinics talk about a baby's age. In the first weeks, doctors often use weeks instead, because newborns change so quickly. You can see the age in weeks and days under the result.

Corrected age for a baby born early

If your baby was born before 37 weeks, tick the box and enter the week of birth. The corrected age moves the date of birth forward by the number of weeks the baby was early, which is the age counted from the original due date. A baby born at 32 weeks was 8 weeks early, so at 16 weeks old the corrected age is 8 weeks.

Doctors often use the corrected age to follow the development of a premature baby in the first years. Ask your pediatrician which age to use.

Using the milestone ranges

The bars come from the WHO growth study. Each bar shows the range in which healthy children reached a skill, and your baby's age is marked on it. Being early or late inside the bar is normal. If your baby is past the end of a bar, or you are worried about development at any age, talk to your pediatrician.

Fun facts

Under the result you will also find the zodiac sign, the birthstone of the month and the Hijri birth date. These are just for fun and say nothing about your baby's health or character.

How to use it

  1. Enter your baby's date of birth.
  2. Leave the second date as today, or change "Age at date" to see the age on another day, for example a clinic visit.
  3. The age appears in months and days, with the age in weeks, the date of the next month mark, the WHO milestone ranges, and fun facts such as the zodiac sign, birthstone and Hijri birth date.

Frequently asked questions

How is a baby's age in months calculated?

We count whole calendar months from the date of birth and the days left over. If your baby was born on the 31st and a month is shorter, the last day of that month counts.

Why do doctors use weeks for a newborn?

Newborns change quickly, so weeks describe their age more precisely than months in the first weeks of life.

What about a baby born early?

Doctors often use a corrected age for a baby born early, counted from the original due date. Tick "my baby was born before 37 weeks" and enter the week of birth to see it next to the actual age. Follow your pediatrician's advice on which age to use.

Is the zodiac sign shown here scientific?

No. It is shown for fun and predicts nothing about your baby. The dates are the standard tropical ones, for example Aries from 21 March to 19 April.

Which Hijri calendar does it use?

The Umm al-Qura calendar, the official one in Saudi Arabia. It can differ by a day or two from other calendars or from local moon sighting, so treat the Hijri age as an estimate.

Is my data sent anywhere?

No. Everything is calculated in your browser and no date is sent to a server.

Sources

  1. Motor development milestones (WHO Child Growth Standards)WHO (World Health Organization)
  2. Corrected Age for PreemiesAmerican Academy of Pediatrics (HealthyChildren.org)
  3. Infant and young child feedingWHO (World Health Organization)

Based on the sources above. This is general information, not medical advice. Ask your doctor about your own situation.