Estimated Tax Penalty

The Internal Revenue Code requires four estimated tax installments a year, each 25 percent of your required annual payment. Miss one and interest runs on that shortfall, computed under section 6621, until you pay it or the year closes. There is no negotiation over the amount; the leverage is in the inputs.

Individuals pay on April 15, June 15, September 15, and January 15 of the following year. Corporations pay on the fifteenth day of the fourth, sixth, ninth, and twelfth months, which for a calendar-year filer means April 15, June 15, September 15, and December 15. Each installment is tested separately, and catching up in December does not undo an April shortfall; it only stops the clock on that installment.

This is one of several IRS penalties that turns on timing rather than fault, which is why the calendar matters as much as the return itself.

The safe harbors that stop the penalty before it starts

An individual owes nothing under section 6654 if total timely payments equal the required annual payment, the lesser of 90 percent of the current year's tax or 100 percent of the tax shown on the prior year's return. If prior-year adjusted gross income exceeded $150,000, or $75,000 for married taxpayers filing separately, the prior-year figure rises to 110 percent.

The prior-year prong is unavailable if the preceding year was not a full twelve months or no return was filed for it. In Mendes v. Commissioner, 121 T.C. 308 (2003), the Tax Court held that a return filed more than two years after the notice of deficiency did not count for safe harbor purposes.

Two exceptions eliminate the penalty outright: under section 6654(e)(1), there is no addition to tax if the tax shown on the return, reduced by withholding, is under $1,000, and under section 6654(e)(2), none applies if you had no tax liability at all in a full prior twelve-month year as a US citizen or resident. Section 6654(h) also removes the fourth-installment penalty if you file and pay the balance in full by January 31.

Uneven income and the annualized income installment method

The four-equal-installments default assumes income arrives evenly. A seasonal business, a large capital gain, or a K-1 landing late in the year all produce a penalty the standard method overstates. Section 6654(d)(2) allows a smaller annualized income installment where income through that point in the year justifies it, using annualizing percentages of 22.5, 45, 67.5, and 90 percent for the first through fourth installments.

Any reduction taken early is recaptured by increasing later installments, so annualizing shifts the obligation rather than erasing it, but shifting is often the entire difference. The method requires a completed Schedule AI with period-by-period income and deductions, which is why many taxpayers skip it and pay a penalty they did not actually owe.

Withholding can cure an underpayment retroactively

Section 6654(g) treats federal income tax withheld from wages as estimated tax paid in four equal parts across the four due dates, regardless of when it was actually withheld, unless the taxpayer proves the actual withholding dates.

A taxpayer who reaches November and realizes the first three installments were short can increase W-2 withholding, or request withholding on a retirement plan distribution, and have that money treated as though a quarter of it was paid back on April 15. Estimated tax payments get no such treatment; they count only when made.

Reasonable cause is not a defense

Courts have been consistent for decades. In Grosshandler v. Commissioner, 75 T.C. 1 (1980), the Tax Court held that the estimated tax addition applies without regard to fault or intent and that the section 6654(e) exceptions are exclusive, a rule followed in Wolfgram v. Commissioner and Wolfington v. Commissioner and by the Tenth Circuit in United States v. Steck, 295 F.2d 682 (1961).

Two narrow waivers exist. Section 6654(e)(3)(A) allows the IRS to waive the addition where casualty, disaster, or other unusual circumstances caused the failure and imposition would be against equity and good conscience, a distinctly higher bar than reasonable cause; reliance on a tax advisor does not qualify. Section 6654(e)(3)(B) covers taxpayers who retired after age 62 or became disabled, where the underpayment was due to reasonable cause and not willful neglect. Waiver requests must be in writing and signed.

Supervisory approval does not apply here

Section 6751(b)(1) has invalidated many IRS penalties where no supervisor personally approved the initial determination in writing, but section 6751(b)(2)(B) expressly excludes additions to tax under sections 6651, 6654, and 6655 from that requirement, confirmed in Burnett v. Commissioner and Dynamo Holdings Ltd. Partnership v. Commissioner, 150 T.C. No. 10 (2018). Time is better spent on safe harbor qualification, annualization, withholding timing, and arithmetic.

Corporations have fewer options

Section 6655 works the same way mechanically but is less forgiving. The corporate required annual payment is the lesser of 100 percent of the current year's tax or 100 percent of the prior year's, with no 90 percent prong. A large corporation, one with taxable income of $1 million or more in any year of the three-year testing period, cannot use the prior-year safe harbor except to compute its first installment, and there is no corporate counterpart to the casualty and disaster waiver.

Farmers and fishermen

Section 6654(i) sets a single required installment, due January 15, for anyone whose gross income from farming or fishing is at least two-thirds of total gross income, substituting two-thirds for the 90 percent figure and disregarding the 110 percent high-income rule. Filing the return and paying in full by March 1 removes the installment penalty.

Estimated tax penalties in Maryland, Virginia, and the District of Columbia

Clearing the federal safe harbor does not clear the state one. Maryland, under Tax-General section 13-702, tests against 90 percent of the current year's tax or 110 percent of the prior year's, with no income limit on the 110 percent figure. Virginia, under sections 58.1-492 and 58.1-504, uses 90 percent of the current year or 100 percent of the prior year, with no step-up at any income level.

The District of Columbia tracks the federal 110 percent rule under sections 47-4203 and 47-4204, with Mayoral waiver authority for individuals but none for corporations.

Why Whiteford

Michael March leads Whiteford's tax controversy practice and handles section 6654 and 6655 disputes at examination, before the IRS Independent Office of Appeals, in collection proceedings, and in the United States Tax Court.

Estimated tax exposure is rarely only federal. Whiteford's tax attorneys practice from offices in Baltimore, Columbia, and Towson, Maryland; Washington, DC; Richmond and Virginia Beach, Virginia; Wilmington, Delaware; and Fairfield, New Jersey, which means a state underestimation assessment and a federal section 6654 addition can be worked as one matter rather than two. Michael takes calls from taxpayers directly, and initial consultations are confidential and complimentary.