For estimated taxes, it doesn't matter where the income came from. You'll have to pay an underpayment
penalty for 2015 if you owe more than $1,000 in taxes (after withholding) and:
- Your taxes withheld don't cover at least 90% of what
you owe for 2015, or
- Your taxes withheld aren't at least 100% of what you
owed for your 2014 taxes, if your adjusted gross income (AGI) is up to
$150,000, or
- Your withholding is 110% if your AGI is more than
$150,000. (The AGI amount is $75,000 if you're married filing separately.)
Even if you owe less than $1,000 (or
have a refund coming) you can still owe an estimated tax penalty if the
payments were not made ratable throughout year.
For example, if you are going to owe taxes and make a large estimated
tax payment late in the year, even one large enough to generate a refund, it
will not negate the penalty for underpayments before that date.
