Baby Age Calculator

Calculate your baby's exact age in months, weeks, and days, plus get upcoming developmental milestones.

Calculate Your Baby Age Calculator

Select your baby's date of birth

Understanding Baby Age Milestones

Tracking your baby's age is more than just counting days—it's about understanding developmental stages, celebrating milestones, and ensuring healthy progress. Parents often track baby age differently than adult age, with weeks and months being more significant markers during the first two years.

Why Tracking Baby Age in Weeks and Months Matters

During the first two years, your baby develops at an astonishing pace. Pediatricians and child development experts use weeks and months as important markers because:

  • Rapid Development: Babies change dramatically week-to-week, especially in the first few months
  • Medical Tracking: Well-baby visits, vaccinations, and developmental screenings are scheduled based on specific age milestones
  • Developmental Expectations: Growth charts and developmental milestones are calibrated to weeks and months, not years
  • Nutritional Needs: Feeding recommendations change frequently during the first year and are based on monthly age

Key Baby Development Milestones by Month

0-3 Months

  • • Holds head up briefly when on tummy (1 month)
  • • First social smiles (2 months)
  • • Follows objects with eyes (2-3 months)
  • • Coos and makes gurgling sounds (2-3 months)
  • • Pushes up on arms when on tummy (3 months)

4-6 Months

  • • Rolls over (4-5 months)
  • • Laughs out loud (4 months)
  • • Shows interest in food (4-6 months)
  • • Sits with support (5 months)
  • • Begins to eat solid foods (6 months)
  • • Babbles with consonant sounds (6 months)

7-9 Months

  • • Sits without support (7-8 months)
  • • Starts crawling (7-10 months)
  • • Responds to name (8 months)
  • • Pulls to stand (8-9 months)
  • • Develops pincer grasp (9 months)
  • • First words may emerge (9 months)

10-12 Months

  • • Cruises along furniture (10-11 months)
  • • Points at objects (10-12 months)
  • • Uses simple gestures like waving (11 months)
  • • May take first steps (11-12 months)
  • • Says 1-3 words with meaning (12 months)
  • • Follows simple instructions (12 months)

The "Adjusted Age" Concept for Premature Babies

For babies born before 37 weeks gestation, healthcare providers often use "adjusted age" or "corrected age" when evaluating development:

  • Calculation: Subtract the number of weeks born early from the baby's actual age
  • Usage: Most providers use adjusted age until around 2 years, especially for significantly premature infants
  • Why It Matters: Using adjusted age provides a more accurate picture of developmental progress for premature babies

Beyond the First Year

After 12 months, parents typically transition from counting age in weeks to months, and eventually to years. However, the CDC and pediatricians still use months as the primary measure until 24 months for growth charts and developmental milestones, after which age is typically measured in years and half-years.

Using Our Baby Age Calculator

Our Baby Age Calculator helps you track your baby's exact age in months, weeks, and days. It also provides information about upcoming developmental milestones to help you understand what changes to expect in your baby's skills and abilities.

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Frequently Asked Questions

The baby age calculator takes your baby's birth date and computes their current age in months, weeks, and days. It also calculates the total number of days since birth and provides information about upcoming developmental milestones based on their age.

Babies develop rapidly during their first two years, with significant changes occurring weekly and monthly. Healthcare providers use these smaller time increments to track development, schedule vaccinations, and assess growth. Monthly and weekly age measurements provide more precise indicators for evaluating whether a baby is reaching developmental milestones within typical timeframes.

Most parents transition from counting in weeks to months around 3 months of age. Healthcare providers may continue to use weeks for premature babies or for specific medical reasons. By 12 months, most parents typically stop counting in weeks entirely and use months until age 2, after which years become the standard measurement.

Adjusted age (also called corrected age) is a way of measuring a premature baby's development based on their due date rather than their actual birth date. To calculate it, subtract the number of weeks the baby was born early from their chronological age. For example, a 6-month-old baby born 8 weeks early has an adjusted age of about 4 months. Doctors typically use adjusted age for developmental assessments until around 2 years of age.

The milestones displayed are based on typical development patterns, but every baby develops at their own pace. Some babies reach certain milestones earlier or later than others while still developing normally. The milestones serve as general guidelines rather than strict rules. If you have concerns about your baby's development, consult with your pediatrician rather than relying solely on standardized milestones.

Months are considered the standard unit for tracking baby age after the first few weeks because they provide a good balance between precision and practicality. Medical professionals use monthly age for growth charts, developmental screenings, and vaccination schedules. Additionally, most baby clothing and developmental products are sized by months, making this measurement particularly useful for parents.

The milestones listed represent average ages when many babies achieve certain skills, based on pediatric research and guidelines from organizations like the American Academy of Pediatrics. However, there's a wide range of what's considered normal development. The milestones are meant to be informative rather than prescriptive. A baby may develop some skills earlier and others later while still being completely healthy.

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