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Quarterly tax questions answered
Questions people sent us, answered with the IRS source cited.
Ask a question →Does my W-2 withholding cover my side income?
Usually not. Your W-4 sizes withholding as if the paycheck were your only income, so the tax on your side income goes unpaid.
w-2 withholdingside incomeself-employmentsafe harborShould I increase my W-2 withholding instead of paying quarterly?
Either works. The IRS treats withholding as paid evenly through the year, so raising it can replace quarterly payments and even fix a late start.
w-2 withholdingsafe harborside incomeDo estimated tax payments count toward the safe harbor rule?
Yes. Withholding and estimated payments both count toward safe harbor. Estimated payments have to arrive by each quarterly deadline to count in full.
safe harborw-2 withholdingdeadlinesWhat happens if I missed a quarterly payment?
Interest starts on the shortfall from the day it was due and grows daily. Pay it as soon as you can, not at the next deadline.
missed paymentdeadlinessafe harborI got a CP30 notice. Can I still lower the underpayment penalty?
Often, yes. The IRS figured it as if your income was even all year. If it was not, send Form 2210 with Schedule AI to the address on the notice.
penalty noticeform 2210annualized incomeI cashed out an inherited IRA and barely anything was withheld. What now?
The distribution is taxable income and the tax may be due this quarter. Check the safe harbor rule first because it may mean nothing is due until April.
retirementwindfallsafe harborCan I have tax withheld from my December RMD instead of paying quarterly?
Yes. Tax withheld counts as paid evenly through the year no matter when it comes out, so one December RMD with enough withholding covers all four quarters.
retirementsafe harborAre quarterly estimated taxes required, or just encouraged?
Required once you expect to owe $1,000 or more after withholding and credits. Skipping them costs the underpayment penalty, which is interest, not a fine.
deadlinessafe harborI paid unevenly but hit the safe harbor total. Am I still safe?
Not automatically. A quarter of the safe harbor amount is due at each deadline. Late installments earn interest unless your income arrived late the same way.
safe harborannualized incomemissed paymentI am confused about estimated tax, the underpayment penalty, and safe harbor. How do they fit together?
One rule, three parts. Estimated tax is paying during the year, the penalty is interest for paying late, and safe harbor is the amount that avoids it.
safe harbordeadlinesWhat is line 38 on Form 1040?
Line 38 is the estimated tax penalty from Form 2210, added to the amount you owe. You can leave it blank and let the IRS figure it.
form 2210penalty noticeI started freelancing mid-year. Do I owe estimated tax for the whole year or only from when I started?
Only from when the income starts. Your first payment is due at the next quarterly deadline, and Schedule AI shows the IRS that nothing was due before that.
self-employmentannualized incomesafe harborIs 22% RSU withholding enough, or will I owe an underpayment penalty?
Not enough if your marginal rate is above 22%. A penalty applies only if your withholding for the year falls below the safe harbor, so check that number first.
w-2 withholdingsafe harbor