There are separate columns for 2 ADULTS (1 WORKING) and 2 ADULTS (BOTH WORKING). I think you are mixing up the two.

And the non-working adult is taking care of children, so reducing childcare expenses.

I am not mixing up the 2

First row, for https://livingwage.mit.edu/counties/06075

    | 1 adult                                        | 2 adults (1 working)                          |
    | 0 Children | 1 Child | 2 Children | 3 Children | 0 Children |1 Child | 2 Children | 3 Children |
    | $29.31     | $61.37  | $83.72     | $107.95    | $41.83     | $50.47 | $54.77     | $63.97     |

    1 adult + 0 children  = $29.31
    2 adults + 0 children = $41.83

The only way these numbers make sense if if you assume one income. Then

    1 adult + 3 kids = $107.95
    2 adults + 3 kids = $63.97

Given the first example was one income, this 2nd one makes no sense. 5 people cost more than 4. These numbers are wrong.

Look at the childcare number in the breakdown table. 1 adult and 3 children has an estimated $71k/year childcare cost, while 2 adults and 3 children (1 working) has a $0/year childcare cost. So some things go up (transportation, healthcare, food), but others go down. Childcare going down by $71k pretty much entirely accounts for the difference you're questioning (~$34/hour difference just on that entry).

Also, two adults (assuming married) will pay lower taxes than one adult for the same income. That's another ~30k difference per year in the breakdown table for the 3 children case. If your tax burden is lower, you can afford a lower wage while bringing in the same net.

EDIT: Tax rates in the US are roughly half (except for high income earners, way beyond these living wage estimates would be relating to) when you're married versus single.

https://www.irs.gov/filing/federal-income-tax-rates-and-brac...

Check out the 22% bracket on that page, the range is doubled for married people filing joint versus single. That's a huge savings each year. Tax savings of two married people and any number of kids is a major contributor to why the living wage drops when someone gets married versus is single with the same number of kids.

1. This is not ai generated.

2. Did you look in the costs breakdown? You'll probs find your answers there.

3. I am guessing having a spare adult to take care of 3 children instead of paying for childcare is probably the difference.

Child care.

that's not either

See the first row in this table: https://livingwage.mit.edu/counties/06075

Compare 2 adults (1 working) 3 kids to 2 adults (both working) 3 kids

First off, you'd expect it to be

     1 adult = X
     2 adults = X + X(0.?) 

Where 0.? is something less than 1 because 2 adults need less than 2x the money

Similarly for kids

     1 kids = Y
     2 kids = Y + Y(0.?)
     3 kids = Y + Y(0.?) + Y(0.?)

You'd expect 2 kids to be less than 2x 1 kid. And you'd expect 3 kids to be les than 1x + 2x 2nd kid. Each kid is cheaper for various reasons like hand-me-downs etc...

But instead, under 2 adults 1 working we see

     1 adult  = $29.31 (from one adult)
     2 adults = $41.83 (so X + X * 0.42)

     2 adults 1 kid  = 50.47
     2 adults 2 kids = 54.77 (so + $4.30)
     2 adults 3 kids = 63.97 (so + $9.19)

Why does the 3rd kid cost more than the 2nd?

Then you can also compare 1 adult 3 kids with 2 adults both working + 3 kids

     1 adult + 3 kids                 = $107.95
     2 adults (both working + 3 kids) = $55.67

Assuming that $55.67 is wages for each that means we're comparing

     1 adult + 3 kids                 = $107.95
     2 adults (both working + 3 kids) = $55.67x2 ($111.34)

We already established that above that adding one adult is only $12.52 a month yet here, suddenly that adult only costs $3.40 a month.

Again, these are nonsense numbers.