The US Bureau of Labor Statistics tracks those expenses individually based on what people actually spend for each decile of the population and came to a different conclusion.
Anecdotally, it is eminently possible to live a modest life on $40k. I know several people that do, and would have no trouble doing so myself if I needed to based on my actual expenses. The idea that Americans can't live on $40k is out of touch with reality; in many parts of the US that is considered a pretty good wage.
It depends on where you live, but if the household only has a single $40k income they would likely be lower-middle class in most of the country. I know people that are raising kids on that, though I wouldn't recommend it. It would only work in a very high cost-of-living area if you were single, though if you have kids you'll receive significant government subsidies. It will only support a simple and unambitious lifestyle but it won't be terrible by any means.
You'll live in a small house or suitable apartment, you'll cook at home almost all the time using inexpensive ingredients, and you'll take inexpensive vacations. You won't have any fancy stuff, aside from one or two special "nice" things, and the stuff you do have you'll use for as long as it is feasible to do so. The most challenging expense will be transportation, because you'll rely on your car and cars are prone to significant random and variable expenses.
Savings won't be enough to cover retirement but you will have a modest amount, you'll mostly be relying on Social Security. Even poor people often have a very modest amount of savings. I know a single mother who amassed $20k savings on a $30k income just by saving for many years.
The ugly part, and one of the main reasons I would not recommend raising a family this way even though I know how, is the social consequences because it comes with a lot of class signals. People in this class are often treated quite shabbily by people that live in the expensive coastal cities, which will impact your kids.
Thanks for spelling out why I think it should be obvious that $40k is
>insufficient pay for a full time career, much less one that requires working far more than 40 hours per week, and take on huge liability working with kids which likely do not have supportive home lives.
There are plenty of other $40k jobs that let you be a desk jockey and browse HN while you work 4 hours per day.
was that after 2000 with student loans? My first few jobs after college where under $40, I think my first year in software I made 42K USD but my rent was $300 and i had no kids. 1996
Rent, auto insurance, food, mobile, retirement savings, clothing, healthcare, taxes, emergency savings. There is no way to fit that all in $40k.
Which I assume must be evident to anyone that has had to pay bills.