Use this baby age calculator to find your baby's exact age in days, weeks, and months from their date of birth. The calculator also shows corrected age for babies born prematurely, identifies the current developmental stage, and tracks upcoming developmental milestones — making it useful for tracking infant age in weeks, checking baby age in months, and comparing progress against typical development timelines.
Whether your baby is a newborn, a few months old, or approaching their first birthday, this tool calculates a precise baby age from any birth date and updates instantly as you type. If your baby was born early, select how many weeks premature to also show corrected age, which is often used when evaluating development in the first two years.
- Age in days: —
- Age in weeks:
— - Age in months: —
- Age in years: —
- Weekday born: —
- Zodiac: —
- Chinese zodiac: —
- Next monthly birthday:
— - First birthday: —
This calculator provides estimates only. For concerns about your child's development, always consult a healthcare professional.
| Age | Milestone | Status |
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Milestones are typical age ranges and vary between children. They are not a substitute for professional assessment.
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Baby Age Calculator — Frequently Asked Questions
How does the baby age calculator work?
Enter your baby's date of birth — the calculator finds today's date automatically and computes the exact age in days, weeks, months, and years. It also identifies the current developmental stage and shows which milestones are upcoming and which have been reached, based on typical timing published by pediatric organisations.
What is corrected age and when should I use it?
Corrected age (also called adjusted age) accounts for prematurity by subtracting the weeks born early from the actual age. For example, a baby who is 3 months old but was born 6 weeks early has a corrected age of about 1.5 months. Healthcare professionals often use corrected age when assessing development in premature babies, typically until the age of 2. Select the number of weeks early in the Born prematurely? field to see your baby's corrected age.
Should I track my baby's age in weeks or months?
Both are useful depending on the context. Weeks are more precise and commonly used during the newborn and early infant stage (roughly the first 3 months), while months become more practical and widely understood from around 3 months onward. Healthcare appointments, feeding guidance, and vaccination schedules often refer to months. This calculator shows both, so you can use whichever is most relevant.
How accurate are the developmental milestones shown?
The milestone ages shown are based on typical ranges published by paediatric health organisations such as the CDC and WHO. They represent the age at which most children reach each milestone, not a strict deadline. Babies develop at different rates — especially premature babies — and minor variation is normal. If your baby has lost skills, is significantly delayed in multiple areas, or you have any concerns, always speak with your healthcare provider.
Can I use this calculator for older babies and toddlers?
Yes. The calculator works for children up to around 5–6 years of age. It will show age in years and months, identify the correct developmental stage (such as Toddler or Preschooler), and display the most relevant milestones. Milestone tracking in the results covers development from birth up to approximately 3 years.
Why does my baby's age in months look slightly different from counting calendar months?
The calculator uses the precise difference between the birth date and today to compute complete months, then adds the remaining weeks and days. This can sometimes differ by a day or two from a rough month count because calendar months have different lengths. The figure shown is mathematically accurate — for example, 3 months and 5 days means exactly 3 complete months plus 5 additional days.
When should I contact a doctor about my child's development?
Speak with a healthcare professional if your baby loses a skill they previously had, shows little interest in faces or interaction, does not respond to sounds, seems unusually floppy or stiff, is not feeding or gaining weight well, or if you simply feel something is not quite right. Trust your instincts — early assessment is always better than waiting.
