People ask how old my baby is, and I'm not sure what to tell them.

He was born May 16, 2016.

Do I give his age in weeks? Days? When should I give it in months?

  • 4
    I'm voting to close this question as off-topic because, while it is parenting related, it's really a math problem. The answer won't be timeless and won't be useful to future visitors in its current form.
    – Becuzz
    Jun 7, 2016 at 13:41
  • As of right now it would be 3 weeks and a day, just counting on the calendar Jun 7, 2016 at 13:53
  • In whichever unit you feel comfortable in or assume who ever you're talking to understands? There is no "standard", so no real question IMHO.
    – Stephie
    Jun 7, 2016 at 17:30
  • @AE I think that's true of the edit from anongoodnurse, but before that the question really was "how many weeks old is my baby", this edit made it a much better question Jun 8, 2016 at 11:28
  • @EricRenouf, oh, I didn't notice it had been edited. ;) Point taken.
    – A E
    Jun 8, 2016 at 11:31

3 Answers 3


You can give your child's age however it suits you. Do not count the day he was born - that is "Day Zero". After that is day 1, 2, etc. Every 7 days is a week.

Generally how people give their child's age depends on how precise they want to be. "Twenty-two days" is fine. "Three weeks" is also fine. Then "three and a half weeks", etc.

Months are counted by the calendar dates; on June 16, he will be one month old.

People often start giving their baby's age in months at about 3 to 4 months of age, and sometimes give an age in months until the second birthday. However you want to report the age is fine.


Here in the UK it's normal to say

"He's x days old"

until he's a week or two old, then say

"He's x weeks old"

until he's about 2 months old, then say

"He's x months old"

until he's 2 years old, then go with years in the usual way, maybe adding in some fractions if you want to be more specific:

"He's two and a half"

Example: NHS Birth-to-5 development timeline

1-4 weeks ... 6-8 weeks

3-5 months ... 15-18 months

1.5-2 years ... 3-5 years

Sometimes medical professionals keep on using months even when the child is no longer an infant (e.g. vaccinations due at '40 months' in the page quoted above) but this is not colloquial usage.


There have been some great answers already. I'll add that I have found personally that when talking to most non parents, rounding to the next half year is easier for them to get the main idea of my child's age without diving into the details.

For example, my much younger coworker was thrown off when I told him my son was "17 months". Instead, I almost corrected that accuracy with "1 1/2" and the conversation was much easier for him.

You have to use a bit of judgement to decide when this may make sense, but I've found that adjusting to my audience makes sense for me.

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