I've tried that estimator and found it to be awkward to use, and does not give good info since my income is from Self-Employment and I make quarterly payments (where I cover expected Federal Income Tax, Medicare and both sides of Social Security). All I want to understand is how to fill out my wife's W4 so that an appropriate amount comes out each pay period. It makes no sense to me that her employer would withhold 0-$5 on a paycheck of $1200, unless we specify an additional amount, and then often that additional amount is all that is withheld. Shouldn't their software calculate out some percentage, like 8% or so, and just withhold that?
