The federal tax code is so confusing; lots of self-employed are getting their tax payments wrong.
Some of the ten million or so are probably cheats, but Houston CPA Bob Fumagalli says the majority are not.
"I don't think the people are cheating the IRS; I mean, the IRS really doesn't care if you pay in or not, they're just gonna charge a penalty, which is basically interest, if you don't pay it in during the year."
Fumagalli is biased, but he recommends a tax preparer.
"If you want to pay in so you don't have a real ugly situation on April 15th then you do indeed need to work with a professional to arrive at that proper amount."
The IRS believes millions of Americans are simply confused.
But Fumagalli says imposing a simple, flat tax might not help.
"A flat tax for someone making a W2 income is going to be different than a flat tax for someone who's self-employed and that's who we're talking about here with having to make these estimated payments are the self-employed individuals."
Fumagalli says those who have to make quarterly earnings estimates should sit down with a professional to make sure they get it right.