For higher income households, standard withholding is insufficient to pay the income taxes owed. For example, one family claimed 4 people last year and the two income earners each did M-0 yet still owed the IRS over $10K.
What method do people use to estimate their additional withholding? Is there a handy calculator?
I've found one on the IRS website for 2014. Should I just use it for 2015 as well?
The calculator seems to leave out a lot of things like 401K deductions, and so forth.