CIT Payment: Deadlines, Methods, and Penalties

A corporate income tax payment is due on the 15th day of the fourth month after the corporation’s tax year ends, which means April 15 for calendar-year C-corporations filing Form 1120.¹ The tax itself must be paid by that original date even if you file an extension, because federal law requires payment at the time fixed for filing without regard to any extension.² Missing that deadline triggers penalties and interest that compound daily, and eventually a federal tax lien that attaches to every asset the corporation owns.

When the Payment Is Due

A calendar-year C-corporation owes any balance for the year by April 15 of the following year.¹ Fiscal-year corporations use the same rule pegged to their own year-end: the 15th day of the fourth month after the close of the tax year. S-corporations filing Form 1120-S run on a different calendar, with returns due the 15th day of the third month after year-end, which is March 15 for calendar-year S-corps.³

If a due date lands on a weekend or federal holiday, the deadline shifts to the next business day. And the annual balance-due payment is only part of the year: most corporations owe quarterly estimated payments as well.

Quarterly Estimated Payments

A corporation that expects to owe $500 or more for the year must make estimated payments in four quarterly installments.⁴ Each installment is 25 percent of the required annual payment. For calendar-year corporations the due dates fall on April 15, June 15, September 15, and December 15. Fiscal-year filers follow the same pattern on the 15th day of the 4th, 6th, 9th, and 12th months of their own tax year.⁵

To avoid an underpayment penalty, total estimated payments have to equal the lesser of 100 percent of the current year’s tax or 100 percent of the prior year’s tax. The prior-year safe harbor is only available if the corporation filed a 12-month return the year before. Large corporations get a narrower version of the break: they can base only the first installment on prior-year tax, and any shortfall gets added to the second installment.⁴

An Extension Does Not Extend the Payment

Filing Form 7004 gives a C-corporation an automatic six-month extension to file its return.⁶ The extension buys time on paperwork only. Payment is still due at the original filing date, calculated without regard to any extension.²

If you expect a balance, estimate the amount and pay it by the original deadline. Any shortfall between what you send and what the return ultimately shows will accrue interest and may pick up failure-to-pay penalties running back to that original due date.

What You Need Before You Pay

Every corporate payment carries a small set of identifiers that route it to the right account and the right period. If any of them is wrong, the IRS can credit the money to the wrong entity or wrong year, and a delinquency notice can arrive even though the payment was on time.

The corporation’s Employer Identification Number, the nine-digit tax ID assigned under 26 U.S.C. § 6109.⁷
The tax form type. Standard C-corporations use Form 1120, S-corporations use Form 1120-S, and foreign corporations with U.S.-source income use Form 1120-F.⁸
The exact tax year the payment applies to. A payment posted to the wrong year can leave one period delinquent while another shows an overpayment.
The payment amount, taken from the return: total tax liability minus credits, prior estimated payments, and other amounts already applied.
The corporation’s legal name and address as they appear in IRS records. If the business has changed names or moved, update the IRS before paying.

How to Pay

Corporations have several payment channels. The right choice depends on how fast the money needs to arrive and whether you’re set up for electronic transactions.

EFTPS

The Electronic Federal Tax Payment System is a free Treasury service and the workhorse for corporate payments.⁹ You can schedule payments online or by phone at 800-555-3453, and the system debits your business bank account on the settlement date you pick.

Enrollment is required before your first payment and asks for your EIN, banking information, and business details. After validation, the IRS mails a PIN within five to seven business days, and you set an internet password during setup.¹⁰ A new corporation cannot enroll and pay on the same day, so plan ahead.

IRS Direct Pay

Direct Pay handles Form 1120 corporate income tax payments without advance enrollment.¹¹ It works for balance-due, estimated, and extension payments, pulls directly from a bank account, and produces an immediate confirmation number.

Same-Day Wire

A same-day wire transfer gets funds to Treasury immediately, which matters when a deadline is hours away.¹² You coordinate with your bank, which uses an IRS-specified format. Expect a wire fee, and check your bank’s cutoff time before you start.

Credit or Debit Card

IRS-approved processors accept card payments. Corporate card processing fees run roughly 2.89 to 2.95 percent of the payment, with a minimum fee of $2.50.¹³ The fees are deductible as a business expense, but on a six-figure balance they add up fast. Cards make more sense for smaller amounts or when timing is critical and other channels aren’t set up.

Check or Money Order by Mail

Paper payments still work. Include Form 1120-V, the payment voucher for corporate income taxes, so the IRS can match the check to your account.⁸ Make the check payable to “United States Treasury” and write your EIN, the tax year, and “Form 1120” on the check itself in case it gets separated from the voucher. Do not staple the check to the voucher. Send the payment to the processing center listed in the Form 1120-V instructions.

Mailed payments carry a risk electronic methods do not. The IRS credits them based on the postmark date, but delivery and processing delays can run weeks. Close to a deadline, electronic payment is safer.

Penalties, Interest, and Liens

Two separate penalties can hit a corporation that misses its obligations, and they can run at the same time.

The failure-to-pay penalty is 0.5 percent of the unpaid tax per month or partial month, capped at 25 percent. If the balance is still unpaid 10 days after the IRS issues a notice of intent to levy, the rate rises to 1 percent per month. The failure-to-file penalty is steeper: 5 percent per month, also capped at 25 percent. For returns required to be filed in 2026, the minimum late-filing penalty when a return is more than 60 days late is the lesser of $525 or 100 percent of the tax owed.¹⁴

Interest runs on top of penalties. The rate is the federal short-term rate plus 3 percentage points, compounded daily, from the original due date until the balance is paid.¹⁴ The standard corporate underpayment rate is 7 percent for the first quarter of 2026 and 6 percent for the second quarter.¹⁵ Large corporate underpayments carry a 2-percentage-point surcharge above the standard rate.

If the tax remains unpaid after the IRS makes a formal demand, a federal tax lien arises automatically and attaches to all property and rights to property the corporation owns, including bank accounts, equipment, receivables, and real estate. The lien is effective as of the assessment date and does not require a public notice to take effect.¹⁶ A filed notice of federal tax lien establishes priority against other creditors, which makes it much harder for the corporation to borrow money or sell assets.

Confirming the Payment Cleared

Electronic payments through EFTPS or Direct Pay produce a confirmation number. Save it with the tax records. Funds move on the settlement date you chose.¹⁰ Log back in to verify the transaction, or check the bank statement within a day or two.

Mailed payments take longer to confirm, and the IRS only follows up on check payments when something is wrong. A canceled check or a bank statement showing the cleared payment is your receipt. If the payment has not cleared within a few weeks of mailing, contact the IRS before penalties start stacking. Catching a processing error early is much easier than unwinding penalties later.

1
Internal Revenue Service. Starting or Ending a Business 3
2
Office of the Law Revision Counsel. 26 USC 6151 – Time and Place for Paying Tax Shown on Returns
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Internal Revenue Service. About Form 1120-S, US Income Tax Return for an S Corporation
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Office of the Law Revision Counsel. 26 USC 6655 – Failure by Corporation to Pay Estimated Income Tax
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Internal Revenue Service. Publication 509 (2026), Tax Calendars
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Internal Revenue Service. Instructions for Form 7004
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Office of the Law Revision Counsel. 26 US Code 6109 – Identifying Numbers
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Internal Revenue Service. About Form 1120, US Corporation Income Tax Return
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Internal Revenue Service. EFTPS: The Electronic Federal Tax Payment System
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Electronic Federal Tax Payment System. EFTPS
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Internal Revenue Service. Types of Business Payments Available Through Direct Pay
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Internal Revenue Service. Same-Day Wire Federal Tax Payments
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Internal Revenue Service. Pay Your Taxes by Debit or Credit Card or Digital Wallet
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Internal Revenue Service. Topic No. 653, IRS Notices and Bills, Penalties and Interest Charges
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Internal Revenue Service. Internal Revenue Bulletin 2026-08
16
Internal Revenue Service. 5.17.2 Federal Tax Liens