How do I estimate my taxes when I have only 1099 income?
"As long as you paid 100% of your last year's tax liability (overall tax liability, the total tax to pay on your 1040) or 90% of the total tax liability this year, or your underpayment is no more than $1000, you won't be penalized as long as you pay the difference by April 15th. That's per the IRS. I don't know where the ""10% of my income"" came from, I'm not aware of any such rule."