Baby Age Calculator

Baby Age Calculator

Enter your baby's date of birth to find their exact age in days, weeks, and months — plus an overview of upcoming developmental milestones.

Date of birth
Baby's date of birth
/ /
DD / MM / YYYY
Born prematurely?
Age today
Age in days
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Age in weeks
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Age in months
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Age in years
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Developmental stage
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Developmental milestones
Age Milestone Status

Milestones are typical age ranges and vary between children. They are not a substitute for professional assessment.

This calculator provides estimates only. For concerns about your child's development, always consult a healthcare professional.

Frequently asked questions about baby age

How does the baby age calculator work?

The calculator uses your baby's date of birth to estimate their age in days, weeks, months and years. It can also show corrected age if your baby was born early.

What is corrected age for a premature baby?

Corrected age adjusts for how many weeks early a baby was born. It is often used when looking at development in babies born prematurely, especially during the first two years.

Should I track my baby's age in weeks or months?

Both can be useful. Weeks are helpful in the newborn stage, while months become more practical as your baby grows. Healthcare professionals often use the format that best matches the developmental question.

Are milestone ages exact?

No. Milestones are typical age ranges, not strict deadlines. Babies develop at different speeds, and premature babies may be assessed using corrected age.

When should I ask a healthcare professional about development?

Ask for advice if your baby loses skills, seems unusually floppy or stiff, is not feeding well, is not responding to sound or interaction, or if your instincts tell you something is not right.