{"id":25578,"date":"2026-11-05T10:28:36","date_gmt":"2026-11-05T10:28:36","guid":{"rendered":"https:\/\/maspartner.com\/?p=25578"},"modified":"2026-11-05T11:07:14","modified_gmt":"2026-11-05T11:07:14","slug":"corporate-estimated-tax-payments-december-15","status":"publish","type":"post","link":"https:\/\/maspartner.com\/en-us\/blog\/corporate-estimated-tax-payments-december-15\/","title":{"rendered":"Corporate Estimated Tax Payments: How C Corps Meet the December 15 Deadline"},"content":{"rendered":"

Quick Answer: <\/span><\/span><\/strong>C corporations expecting to owe $500 or more in federal income tax (after credits) <\/span>generally make<\/span> four estimated tax payments during the year. For calendar-year corporations, the 2026 deadlines are April 15, June 15, September 15, and December 15. Each installment is <\/span>generally 25%<\/span> of the required annual payment, subject to applicable calculation methods and exceptions.<\/span><\/span><\/p>\n

Missing a corporate estimated tax payment deadline can result in IRS underpayment penalties, even when the annual tax return is filed on time. Unlike individuals, whose final estimated tax installment is generally due in January, calendar-year corporations must complete their fourth payment in December.<\/span>\u00a0<\/span><\/p>\n

This guide explains payment eligibility, installment calculations, safe harbor rules, electronic payment methods, and how businesses can manage potential underpayment penalties.<\/span><\/p>\n

<\/span>When Are Corporate Estimated Tax Payments Due?<\/span><\/b>\u00a0<\/span><\/span><\/h2>\n

Corporate estimated tax payments follow a quarterly installment schedule determined by the corporation’s tax year. For calendar-year C corporations, the following table outlines the 2026 payment deadlines and cumulative payment requirements.<\/span>\u00a0<\/span><\/p>\n

<\/span>The Four Installment Dates<\/span><\/b>\u00a0<\/span><\/span><\/h3>\n
\n\n\n\n\n\n\n\n\n
Installment<\/th>\n2026 due date<\/th>\nCumulative share due<\/th>\n<\/tr>\n<\/thead>\n
First<\/td>\nApril 15<\/td>\n25%<\/td>\n<\/tr>\n
Second<\/td>\nJune 15<\/td>\n50%<\/td>\n<\/tr>\n
Third<\/td>\nSeptember 15<\/td>\n75%<\/td>\n<\/tr>\n
Fourth<\/td>\nDecember 15<\/td>\n100%<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

<\/span>Fiscal-Year Corporations<\/span><\/b>\u00a0<\/span><\/span><\/h3>\n

Corporations using a fiscal year calculate their installment deadlines from the beginning of their tax year. Payments generally fall on the 15th day of the fourth, sixth, ninth, and twelfth months.<\/span>\u00a0<\/span><\/p>\n

As a result, December 15 may not be the final payment deadline for every corporation. For example, a corporation whose tax year ends June 30 pays on October 15, December 15, March 15, and June 15. If a due date falls on a Saturday, Sunday, or legal holiday, the installment is due on the next business day. None of the 2026 calendar-year due dates falls on a weekend. Businesses should also check applicable state estimated tax requirements, which may differ from federal rules.<\/span>\u00a0<\/span><\/p>\n

Importantly, an extension of time to file Form 1120 does not postpone estimated tax installments or extend the time to pay the tax. See our Business Tax Extension Deadlines guide for additional information about return filing dates.<\/span><\/p>\n

<\/span>Why the Final Payment Falls on December 15, Not January 15<\/span><\/b>\u00a0<\/span><\/span><\/h2>\n

<\/span>Corporations and Individuals Follow Different Rules<\/span><\/b>\u00a0<\/span><\/span><\/h3>\n

Corporate and individual estimated tax payments follow different schedules under the Internal Revenue Code.<\/span>\u00a0<\/span><\/p>\n

Section 6655 establishes corporate installment deadlines based on the fourth, sixth, ninth, and twelfth months of the tax year. By comparison, Section 6654 generally places the final individual estimated tax installment in January of the following year.<\/span>\u00a0<\/span><\/p>\n

This distinction matters for business owners who manage both personal and corporate tax obligations. Applying the individual January deadline to a calendar-year corporation could result in a late fourth installment and potential underpayment penalties.<\/span><\/p>\n

<\/span>Which Corporations Must Make Estimated Tax Payments?<\/span><\/b>\u00a0<\/span><\/span><\/h2>\n

C corporations generally must make estimated tax payments when they expect their federal income tax liability, after applicable credits, to reach $500 or more.<\/span>\u00a0<\/span><\/p>\n

This requirement also applies to LLCs that have elected to be taxed as C corporations.<\/span>\u00a0<\/span><\/p>\n

S corporations follow different rules because their income generally passes through to shareholders. However, an S corporation may have estimated tax payment obligations when the total of its built-in gains tax, excess net passive income tax, and investment credit recapture tax is $500 or more.<\/span>\u00a0<\/span><\/p>\n

Understanding these distinctions helps businesses determine whether quarterly payments are required before calculating their installment amounts.<\/span>\u00a0<\/span><\/p>\n

<\/span>Form 1120-W Is Retired: Use the Publication 542 Worksheet<\/span><\/b>\u00a0<\/span><\/span><\/h2>\n

Form 1120-W and its instructions are now classified by the IRS as historical, and the 2022 revisions were the last ones issued. Corporations can instead use the Estimated Tax Worksheet provided in <\/span>IRS Publication 542<\/span><\/a> as a guide to figure each required estimated tax installment.<\/span>\u00a0<\/span><\/p>\n

Using current IRS guidance helps businesses apply the appropriate calculation methods and avoid relying on outdated forms.<\/span>\u00a0<\/span><\/p>\n

<\/span>How Do C Corporations Calculate Each Installment?<\/span><\/span>\u00a0<\/span><\/span><\/h2>\n

\"\"<\/p>\n

<\/span>Project Taxable Income<\/span><\/b>\u00a0<\/span><\/span><\/h3>\n

Estimate full-year revenue and deductions, using year-to-date results and expected activity, to reach projected taxable income.<\/span>\u00a0<\/span><\/p>\n

<\/span>Apply the Corporate Rate<\/span><\/b>\u00a0<\/span><\/span><\/h3>\n

Multiply taxable income by the flat 21% federal rate, subtract expected credits, and add any other taxes the corporation expects to owe to find expected annual tax.<\/span>\u00a0<\/span><\/p>\n

<\/span>Divide Into Four Installments<\/span><\/b>\u00a0<\/span><\/span><\/h3>\n

The required annual payment is generally divided into four equal installments of 25% each. The required annual payment itself is generally the smaller of the current-year figure and, if the corporation is eligible, the prior-year figure, as explained in the safe harbor section below.<\/span>\u00a0<\/span><\/p>\n

<\/span>A Worked Example<\/span><\/b>\u00a0<\/span><\/span><\/h3>\n

Assume projected 2026 taxable income of $400,000. At 21%, expected tax is $84,000. The 2025 tax was $60,000.<\/span>\u00a0<\/span><\/p>\n

Assuming the corporation is not a large corporation and its 2025 return covered a full 12 months and showed a positive tax liability, it qualifies for the prior-year method described below. The required annual payment is then the lower figure, $60,000, and each installment is $15,000. Paying these installments on time generally avoids the underpayment penalty, but the remaining $24,000 of expected tax is still owed and is generally due by the original due date of the 2026 Form 1120, not including extensions.<\/span>\u00a0<\/span><\/p>\n

<\/span>Revisit Before Each Date<\/span><\/b>\u00a0<\/span><\/span><\/h3>\n

Refresh the projection before every payment date, especially in December, when the year\u2019s results are nearly known. If an earlier installment turns out to be too low, an immediate catch-up payment can reduce the underpayment penalty.<\/span>\u00a0<\/span><\/p>\n

<\/span>What Are the Safe Harbor Rules for Corporate Estimated Taxes?<\/span><\/b>\u00a0<\/span><\/span><\/h2>\n

Corporate estimated tax safe harbor rules provide methods for determining installment amounts that generally protect businesses from underpayment penalties when the applicable requirements are met. Publication 542 describes these rules as Method 1 (current year) and Method 2 (prior year).<\/span>\u00a0<\/span><\/p>\n

\"\"<\/p>\n

Corporations may generally calculate their required annual payment using either method below, and typically use whichever produces the smaller payment:<\/span>\u00a0<\/span><\/p>\n