When would you consider them one-month-old?

Usually I go by the weeks, not the date. If it has been four weeks since the birth, they are one month old. But after a while it gets hard to track so then I would probably go by the date.

I would be glad when they are 2 years old and we don’t age them by month!

Unlike @janbb, I don’t use weeks to approximate months because that is off by 10% after a month! I would use the arrival of the date in the next month.

Born July 15, one month on August 15. Born August 15, one month on September 15.Born February 15, three months on May 15.

And really, once they are five or six months old, precision to the day is pointless.

What @zenvelo said.

But she was specifically referring to people who are born on a date that isn’t always reoccurring, IE the 31st.

To me a month is a month whether it was 28 days or 31 days long. When my boys were born, we stated their age at first by days for the first month, the second month we stated their ages by weeks 6 weeks old. Then the 3rd month it was a combo of months and weeks or a fraction…..3½ old. After the 1st birthday it was 1 year x number of months old. That pretty much carried on until their teenage years when it became just turned 13…he’s almost 15 now. Hell time is flying so fast now for me I can say I just turned 55 and am almost 56 in the same breath! lol

@Dutchess_III Then you treat it like born on February 29. Born on August 31? Then on Sept 30, “almost a month”; and on October 1, “just past a month”.

My daughter was born on the 31st of the month and to me, the last day of the month was her “one month,” “two months,” “three months,” etc. When there’s a whole bunch of months behind them, months themselves no longer matter, and then it’s “almost a year” etc.

I would go with the last day of any month without 30 days. Born October 31st? One month old on November 30th. Months aren’t a standardized unit of measurement, so it’s actually correct to say that someone has lived through an entire month at that point.

To add to what I wrote above, I think that most people, when they ask, don’t really care if it’s “almost a month” or “33 days” or whatever. If you say “he’s three months old” that means a general figure, not necessarily to the day.

I would hold out for the first one-year birthday, when I’d get a piece of cake.

The first few to several weeks of life I would use weeks. If born on a Friday, every Friday would mark a new week. By two months I would just count the last day of the month as two months if the child was born in the 31st. I don’t think here is any hard and fast rule though. Children born on Leap Day, the parents decide whether to declare the birthday February 29 or March 1. Both are acceptable, but I prefer the February choice.

I agree with the people above who say it doesn’t need to be exact. People say 4 months and it could be off by 5 days, it doesn’t matter. Like when a woman is pregnant, is she 3 months? Three lunar months? Three months from conception? Three months from missed period? The doctor, woman herself, and soon to be dad might be interested in which count is being used, and they might use weeks, but everyone else is fine if you round the number to a near month count.