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Indiana Business State Tax Extension I C Corporations Filing Guide

Form E-6 | Request for Indiana Corporate Estimated Quarterly Income Tax Returns (Form IT-6)  ·  C Corporations  ·  Business Filing Guide

Overview

Indiana C Corporations are subject to state corporate income tax requirements, administered by the Indiana Department of Revenue. Indiana grants an automatic extension tied to an approved IRS extension, making the process simple for businesses that have already filed IRS Form 7004.

Original Filing Deadline

• The original due date for the Indiana C Corporations return is April 15, 2026. File or remit full payment by this date to remain in good standing.
• Extension Period & Extended Deadline
• Indiana automatically grants an extension to file, provided you have obtained an approved federal extension from the IRS by filing IRS Form 7004. With a valid IRS extension, the Indiana extended deadline becomes November 15, 2026. No separate state extension form is required—the federal extension serves as your Indiana extension.

Payment Is Still Due by Original Deadline

The extension applies to filing only—it is not an extension to pay taxes owed. Any outstanding tax liability must be paid by the original due date of April 15, 2026 to avoid penalties and interest. Use the Indiana | Online Tax Extension Payment to pay electronically. For mail-in payments, use Form E-6 | Request for Indiana Corporate Estimated Quarterly Income Tax Returns (Form IT-6) and send to: Indiana Department of Revenue Corporate Tax Division P.O. Box 7228 Indianapolis, IN 46207-7228

Late Filing and Payment Penalties

• Failure to File: 10% penalty of amount of tax due.
• Failure to Pay: 10% penalty of amount held in trust.

Best Practices

• Estimate and pay your Indiana business tax by April 15, 2026 to avoid interest and penalties.
• File IRS Form 7004 with the IRS to secure your federal extension, which Indiana automatically honors.
• Use the state online payment portal for fast, convenient electronic payment.
• Set a reminder to file your completed Indiana C Corporations return by November 15, 2026.

Final Thoughts

• Indiana’s business tax extension is straightforward once your federal extension is approved. Pay 100% of any tax due by April 15, 2026 and file your C Corporations return by November 15, 2026.
• Quick Reference Table
• State Abbreviation
• IN
• State Name
• Indiana
• Business Entity Type
• C Corporations
• Extension Status
• Approved with Federal
• Return Due Date
• April 15, 2026
• Extended Due Date
• November 15, 2026
• Other Information
• Indiana grants your business an automatic 6-month extension provided you have obtained an approved IRS extension. The extension is NOT an extension to pay any taxes you may have due. Tax payments are due by the original return due date. Federal extension form must be attached to return and extension box must be checked on front page of return.
• Online Payment
• Indiana | Online Tax Extension Payment
• Payment Voucher Form
• Form E-6 | Request for Indiana Corporate Estimated Quarterly Income Tax Returns (Form IT-6)
• State Payment Agency
• Indiana Department of Revenue
• Mailing Address with Payment
• Indiana Department of Revenue Corporate Tax Division P.O. Box 7228 Indianapolis, IN 46207-7228
• Failure to File Penalties
• 10% penalty of amount of tax due.
• Failure to Pay Penalties
• 10% penalty of amount held in trust.

Working with a Tax Professional

Business tax returns are complex—a licensed CPA or Enrolled Agent can maximize deductions, ensure accurate calculations, and handle filing on your behalf. Here's how working with a TaxPro typically goes:

1. 1Get matched with a verified U.S.-based CPA or Enrolled Agent
2. 2Upload your business documents via secure drag-and-drop
3. 3Review and approve your return with upfront, transparent fees
4. 4Your TaxPro files your Indiana return by November 15, 2026

Quick Reference Table

State Abbreviation	IN
State Name	Indiana
Business Entity Type	C Corporations
Extension Status	Approved with Federal
Return Due Date	April 15, 2026
Extended Due Date	November 15, 2026
Other Information	Indiana grants your business an automatic 6-month extension provided you have obtained an approved IRS extension. The extension is NOT an extension to pay any taxes you may have due. Tax payments are due by the original return due date. Federal extension form must be attached to return and extension box must be checked on front page of return.
Online Payment	Indiana | Online Tax Extension Payment
Payment Voucher Form	Form E-6 | Request for Indiana Corporate Estimated Quarterly Income Tax Returns (Form IT-6)
State Payment Agency	Indiana Department of Revenue
Mailing Address with Payment	Indiana Department of Revenue Corporate Tax Division P.O. Box 7228 Indianapolis, IN 46207-7228
Failure to File Penalties	10% penalty of amount of tax due.
Failure to Pay Penalties	10% penalty of amount held in trust.