US median individual wage is $39K/yr for males and $26.5K/yr for females [1]. That amounts to an after-total-tax (for a California resident) of $28K/yr for males and $19K/yr for females.

The tax calculator you reference includes estimates of sales, property, and fuel taxes (which make up much of the tax total at the incomes here), which are actually rolled into rent, transportation, and general purchases, so you are double counting some expenses.