2026 Tax Deadline Calendar for C-Corporations
All IRS due dates for C-Corporations in 2026, including Form 1120 filing, estimated tax payments, W-2/1099 deadlines, and extension dates.
C-Corporations file Form 1120 and pay corporate income tax at the 21% flat rate. Unlike pass-through entities, C-Corps pay tax at the entity level. The corporate return is due April 15, and the corporation itself must make quarterly estimated payments if it expects to owe $500 or more.
Showing 6 deadlines for C-Corporation
Next Deadline
1099 Forms Due (Paper Filing)
6 days
Feb 28
January 2026
W-2 and 1099-NEC Filing Deadline
InformationEmployers must send W-2s to employees and file with SSA. 1099-NECs due to contractors and IRS.
February 2026
1099 Forms Due (Paper Filing)
InformationPaper-filed 1099-MISC, 1099-INT, 1099-DIV due to IRS (electronic deadline is March 31)
March 2026
1099 Forms Due (Electronic Filing)
InformationElectronically-filed 1099-MISC, 1099-INT, 1099-DIV due to IRS
April 2026
Individual/C-Corp Extension Deadline
ExtensionFile Form 4868 (individuals) or Form 7004 (C-Corps) to request 6-month extension
October 2026
Extended Individual & C-Corp Returns Due
FilingExtended Form 1040 and Form 1120 returns due
Key Tax Tips for C-Corporations
Corporate Estimated Payments
C-Corps must make quarterly estimated payments using Form 1120-W if the corporation expects to owe $500 or more in taxes. Deposits are made via EFTPS (Electronic Federal Tax Payment System).
Double Taxation
C-Corp profits are taxed at the corporate level (21%) and again when distributed as dividends to shareholders. Plan distributions carefully to minimize the combined tax burden.
April 15 Filing Deadline
C-Corp returns (Form 1120) are due April 15 for calendar-year filers. File Form 7004 for an automatic 6-month extension to October 15, but pay estimated taxes by April 15.
C-Corporation Tax Deadline FAQs
When is the C-Corp tax return due in 2026?
Form 1120 for calendar-year C-Corporations is due April 15, 2026 for the 2025 tax year. You can file Form 7004 for an automatic 6-month extension, moving the deadline to October 15, 2026. Estimated taxes owed must still be paid by April 15.
Do C-Corporations make quarterly estimated tax payments?
Yes. C-Corps must make quarterly estimated payments if they expect to owe $500 or more in taxes. Payments are due on the 15th day of the 4th, 6th, 9th, and 12th months of the tax year. For calendar-year C-Corps, that is April 15, June 15, September 15, and December 15.
What is the corporate tax rate for C-Corporations?
C-Corporations pay a flat 21% federal corporate income tax rate on taxable income. This rate was established by the Tax Cuts and Jobs Act of 2017. State corporate taxes apply in addition, varying by state.
What W-2 and 1099 deadlines apply to C-Corps?
C-Corps must file W-2 forms for all employees by January 31. 1099-NEC forms for contractors paid $600 or more are also due January 31. Paper 1099-MISC forms are due February 28, and electronic 1099-MISC forms are due March 31.
What is the penalty for late C-Corp filing?
The failure-to-file penalty is 5% of unpaid taxes per month, up to 25%. The failure-to-pay penalty is 0.5% per month. If both apply, the combined penalty is 5% per month for the first 5 months, then 0.5% thereafter. Interest also accrues on unpaid balances.
Official IRS References
- IRS Publication 509: Tax Calendars
Official IRS calendar of tax deadlines
- IRS Estimated Taxes Guide
Information on quarterly estimated tax payments
- IRS: When to File
Filing deadlines and extension information
Deadlines may change due to holidays, weekends, or IRS announcements. Always verify current deadlines on IRS.gov.