A C corporation that expects to owe $500 or more in federal income tax for the year must make corporate estimated tax payments in four quarterly installments, or the IRS will assess an automatic underpayment penalty under IRC Section 6655.1Internal Revenue Service. Underpayment of Estimated Tax by Corporations Penalty The threshold is measured as total expected tax minus credits. Tax-exempt organizations with unrelated business income, private foundations, and S corporations owing certain entity-level taxes face the same obligation.2Internal Revenue Service. Instructions for Form 2220 (2025)
S corporations don’t usually owe income tax at the entity level because profits pass through to shareholders. They still owe estimated payments if combined entity-level taxes reach $500, specifically the tax on built-in gains, excess net passive income tax, and investment credit recapture tax.3Internal Revenue Service. Businesses – Estimated Tax FAQs This typically comes up after a C-to-S conversion when the corporation still holds appreciated assets from its C years.
How to Calculate Each Installment
Each quarterly installment equals 25 percent of the “required annual payment,” which is the lesser of two figures:4Office of the Law Revision Counsel. 26 USC 6655 – Failure by Corporation to Pay Estimated Income Tax
- 100 percent of the tax the corporation expects to owe for the current year, or
- 100 percent of the tax shown on last year’s return, provided that return covered a full 12-month year and showed some tax liability.
The prior-year method gives corporations with unpredictable income a safe baseline. If last year’s tax was $200,000, paying $50,000 each quarter meets the requirement no matter what this year’s tax turns out to be. The trade-off is that overpayments have to wait for a refund. A corporation projecting a much weaker year can instead base its payments on 100 percent of current-year expected tax.
Underestimating early is not fatal. A corporation can increase later installments to catch up, and doing so sooner reduces the penalty exposure on the earlier shortfalls, because the IRS evaluates each quarter independently.
The Rule for Large Corporations
A large corporation for Section 6655 purposes is one that reported taxable income of $1 million or more in any of the three preceding tax years. Controlled groups split the $1 million threshold among members. Taxable income for this test ignores net operating loss carrybacks and capital loss carryovers, so a carryback that wipes out a prior year won’t undo large-corporation status.4Office of the Law Revision Counsel. 26 USC 6655 – Failure by Corporation to Pay Estimated Income Tax
Large corporations may use the prior-year method only for the first installment. Every payment after that must be based on 100 percent of current-year projected tax. And the reduction taken on the first installment by using last year’s number gets added back to the second installment.4Office of the Law Revision Counsel. 26 USC 6655 – Failure by Corporation to Pay Estimated Income Tax This is the rule that catches finance teams off guard. The first-quarter payment goes out at last year’s comfortable figure, then the second-quarter payment lands much larger because it carries the recapture.
Payment Due Dates
Installments are due on the 15th day of the 4th, 6th, 9th, and 12th months of the corporation’s tax year.5Internal Revenue Service. Publication 509 – Tax Calendars For a calendar-year corporation:
- First installment: April 15
- Second installment: June 15
- Third installment: September 15
- Fourth installment: December 15
Fiscal-year corporations follow the same pattern mapped to their own year-end. When a due date falls on a Saturday, Sunday, or legal holiday in the District of Columbia, the deadline shifts automatically to the next business day.5Internal Revenue Service. Publication 509 – Tax Calendars
How to Make the Payment
Corporations pay through the Electronic Federal Tax Payment System (EFTPS), and the IRS also accepts corporate payments through its Business Tax Account portal and Direct Pay for businesses.6Internal Revenue Service. Estimated Taxes In EFTPS, the corporation selects Form 1120 as the tax type and enters the correct tax year and quarter along with the amount.7Internal Revenue Service. EFTPS Payment Instruction Booklet
New EFTPS users have to plan ahead. After online enrollment, the IRS mails a PIN to the address of record, and delivery takes five to seven business days.8Electronic Federal Tax Payment System. Welcome to EFTPS A corporation registering the week before its first installment will miss the deadline. EFTPS lets users schedule payments in advance, and the confirmation number generated after each payment is the corporation’s proof of timely filing if the IRS ever questions the date.
Form 1120-W is available as a worksheet for computing the installments. It’s optional and never filed with the IRS.9Internal Revenue Service. Instructions for Form 1120-W (2022) Revisiting the calculation before each quarter is worthwhile when income or deductions have shifted materially.
Alternatives for Uneven Income
Corporations whose income doesn’t arrive evenly can use one of two alternative methods, both computed on Schedule A of Form 2220. Once elected, the method applies to all four installments for the year.10Internal Revenue Service. Instructions for Form 2220
Annualized Income Installment Method
This method computes each installment from the actual income earned in a defined portion of the year, then annualizes that figure. The standard measurement periods are 3 months for the first two installments, 6 months for the third, and 9 months for the fourth.11eCFR. 26 CFR 1.6655-2 – Annualized Income Installment Method
A corporation can elect different measurement periods (either 2, 4, 7, and 10 months or 3, 5, 8, and 11 months) by filing Form 8842 by the 15th day of the fourth month of the tax year. The election applies to that year only and cannot be revoked once made.12Internal Revenue Service. Form 8842 – Election To Use Different Annualization Periods for Corporate Estimated Tax
Adjusted Seasonal Installment Method
To qualify, the corporation must have earned at least 70 percent of its taxable income in the same six consecutive months in each of the three preceding tax years.10Internal Revenue Service. Instructions for Form 2220 Resort operators concentrated in summer and retailers dependent on holiday sales are typical candidates. The method uses the historical pattern to shift installment sizes toward the months when the income actually shows up.
When Schedule A is completed, the IRS picks the smallest required installment from the regular, annualized, and seasonal calculations for each due date. Any reduction taken through the alternative methods gets recaptured in later installments, so the methods shift timing rather than reducing total tax.
How the Underpayment Penalty Works
The penalty is not a flat fee. It runs as an interest charge on each underpaid installment from the installment’s due date until the earlier of the date the corporation pays or the 15th day of the fourth month after the tax year closes (April 15 for calendar-year filers).4Office of the Law Revision Counsel. 26 USC 6655 – Failure by Corporation to Pay Estimated Income Tax
The underpayment rate is the federal short-term rate plus three percentage points, updated quarterly.13Office of the Law Revision Counsel. 26 USC 6621 – Determination of Rate of Interest For the first quarter of 2026 the standard corporate underpayment rate is 7 percent, dropping to 6 percent in the second quarter.14Internal Revenue Service. Quarterly Interest Rates An underpayment spanning multiple quarters may be charged at different rates for different portions of the period.
Each installment is assessed on its own. Missing only the second quarter means the penalty applies to that shortfall alone. Payments are credited to installments in the order they came due, so an early or extra payment can’t be redirected to cover a later quarter.4Office of the Law Revision Counsel. 26 USC 6655 – Failure by Corporation to Pay Estimated Income Tax A corporation ending the year with a refund can still owe an underpayment penalty for the quarters it fell short.
Higher Rate on Large Underpayments
C corporations with underpayments exceeding $100,000 pay the federal short-term rate plus five percentage points, two points above the standard rate.15eCFR. 26 CFR 301.6621-3 – Higher Interest Rate Payable on Large Corporate Underpayments For the first quarter of 2026 that works out to 9 percent versus the standard 7 percent.14Internal Revenue Service. Quarterly Interest Rates The $100,000 threshold is measured as the difference between tax owed and tax paid by the return’s due date, not per installment. Once the underpayment crosses that line, the higher rate applies to the entire excess.
Form 2220
The IRS ordinarily calculates the penalty and sends a notice, so most corporations don’t file Form 2220 on their own. The main reason to file it proactively is to show the use of the annualized income or adjusted seasonal method, since the IRS won’t apply those calculations unless a completed Form 2220 and Schedule A are attached to the return.10Internal Revenue Service. Instructions for Form 2220
No Reasonable-Cause Waiver
Unlike most IRS penalties, the estimated tax penalty has no reasonable-cause exception.16Internal Revenue Service. Penalty Relief for Reasonable Cause Once the math shows a shortfall, the penalty applies regardless of why the corporation fell behind. The only routes to reduce it are mathematical: showing through the annualized income or adjusted seasonal method that the actual income pattern justified smaller payments earlier in the year.10Internal Revenue Service. Instructions for Form 2220
Federally declared disasters are the exception. The Treasury Secretary can designate a period of up to one year to be disregarded in evaluating whether payments were timely, and IRC Section 7508A(d) provides a mandatory 60-day postponement for taxpayers affected by major disasters declared after November 2021. The IRS identifies businesses in covered disaster areas and applies relief automatically. Corporations located outside the disaster zone whose records or tax professional are inside it may need to call the IRS disaster hotline at 1-866-562-5227.17Internal Revenue Service. 20.1.3 Estimated Tax Penalties
Getting Back an Overpayment Quickly
A corporation that overpaid its estimated tax can request a quick refund on Form 4466 without waiting for the annual return. The overpayment must be at least $500 and at least 10 percent of the corporation’s expected tax liability.18Internal Revenue Service. Instructions for Form 4466
The window is narrow. Form 4466 must be filed after the tax year ends, before the corporation files its income tax return, and no later than the return’s original due date. A filing extension for the return does not extend the Form 4466 deadline.18Internal Revenue Service. Instructions for Form 4466 For a calendar-year corporation, the request has to reach the IRS by April 15. Missing that window means waiting for the refund to process with the annual return.
State Payments Are Separate
Federal estimated payments do not satisfy state obligations. Most states with a corporate income tax impose their own estimated payment requirements, with minimum thresholds typically ranging from $400 to $5,000, and their own due dates, installment percentages, and penalty calculations. Corporations operating in multiple states have to track each state’s rules independently, because a missed state installment triggers a separate state penalty.