Calendar months
A baby turns one month old on the same date in the following month. Because months vary in length, “4 weeks” and “1 month” aren’t quite the same.
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How many months old is my baby?
Convert your baby’s age into exact calendar months.
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Counting in months
When to switch to years
Many parents count in months until 18 or 24 months, then move to years and months.
Need more detail?
The Baby Age Calculator shows years, months, weeks, days and upcoming milestones.
FAQ
Questions parents ask
How many weeks are in a month?
On average about 4.35 weeks. That’s why 12 weeks is a little less than 3 months.
Is a baby 1 month old at 4 weeks?
Not quite — they’re 1 month old on the same date the following month, which is usually 4 weeks and a few days.
Is anything stored?
No. Everything is calculated in your browser.