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Wajiha Danish
Wajiha Danish is a Chartered Professional Accountant (CPA, CGA) and the Director at Monily Finance and Accounting LLC. With over 20 years of experience in accounting, financial reporting, audit, and finance operations, she has held senior roles across multinational, energy-sector finance teams, and public accounting. Wajiha is proficient in both US GAAP and IFRS, enabling her to support businesses with complex reporting and compliance requirements.
View ProfileIt depends on the type of corporation and the corporation’s tax year.
C corporation
A corporation filing Form 1120 generally must file its federal income tax return by the 15th day of the 4th month after the end of its tax year. For a calendar-year 2025 return, the deadline is April 15, 2026. There is a special rule for a corporation with a fiscal tax year ending June 30: it generally files by the 15th day of the 3rd month after the end of its tax year. If the due date falls on a Saturday, Sunday, or legal holiday, the deadline moves to the next business day.
S corporation
An S corporation filing Form 1120-S generally must file by the 15th day of the 3rd month after the end of its tax year. For a calendar-year 2025 return, the deadline is March 16, 2026, because March 15, 2026 falls on a Sunday. If the due date falls on a Saturday, Sunday, or legal holiday, the deadline moves to the next business day.
Important related note
If a corporation needs more time to file, it generally requests an automatic extension on Form 7004, and that extension request generally must be filed by the regular due date of the return.
State Law Note
State corporate income tax, franchise tax, and related filing deadlines are administered at the state level and may differ from the federal deadlines above. The controlling authority is the applicable state revenue department or tax agency.
Sources
IRS — Instructions for Form 1120 (2025)
IRS — About Form 1120, U.S. Corporation Income Tax Return
IRS — 2025 Instructions for Form 1120-S
IRS — About Form 1120-S, U.S. Income Tax Return for an S Corporation
This information provided does not, and is not intended to, constitute legal advice.