2026 Indiana State Tax Deadlines
Indiana Individual income tax filing deadlines and extensions for 2026
If you are a resident or have been involved in business operations within Indiana, you might be required to file Indiana State taxes. Indiana follows a flat income tax structure with a 3.23% rate, making it essential to understand the specific deadlines and requirements for 2026.
Indiana business tax deadlines for 2026
C Corporations' deadlines and requirements
C Corporations in Indiana must file and pay Corporate Income Tax by April 15, 2027, following the federal due date schedule.
Filing requirements include:
- Complete Form IT-20 (Indiana Corporation Income Tax Return)
- File via INTIME
- Payment must be made by April 15, 2027
- Mail submissions must be postmarked by the due date
Extension to file taxes in Indiana for 2026
The Extension Deadline for Indiana Corporate income tax returns is October 15, 2027. Indiana automatically grants a six-month extension following the federal extension timeline without requiring separate forms. This is an extension to FILE, not an extension to PAY—payment is still due April 15, 2027.
Pass-through entities
Indiana S Corporations and Partnerships tax deadlines for 2026
S Corporations and Partnerships must file in Indiana by March 15, 2027.
Required forms include:
- Form IT-20S—S Corporation Return
- Form IT-65—Partnership Return
Extension to file S Corporations and Partnerships taxes in Indiana for 2026
The Extension Deadline for Indiana S Corporations and Partnerships returns is September 15, 2027. Indiana automatically grants a six-month extension without requiring separate applications. This is an extension to FILE, not an extension to PAY—payment is still due March 15, 2027.
Indiana Individual tax considerations for 2026
Filing requirements and income thresholds
Indiana Individuals must file a State income tax return if their gross income exceeds specific thresholds based on filing status.
The flat tax rate for 2026 is:
- 3.23% on all Indiana taxable income
Estimated tax deadline for Indiana 2026
Estimated tax payments are due on the following schedule for calendar year filers:
- April 15, 2026
- June 15, 2026
- September 15, 2026
- January 15, 2027
Who must make estimated payments
You must make Indiana estimated income tax payments during 2026 if you expect to owe a significant amount in Indiana income tax after subtracting withholding and credits. Electronic payments are encouraged through the Indiana online tax system.
Individual tax deadline for Indiana 2026
Individual income tax returns are due April 15, 2027.
Available forms include:
- Form IT-40—Indiana Individual Income Tax Return
- Form IT-40PNR—Part-Year Resident and Nonresident Individual Income Tax Return
Extension to file taxes in Indiana for 2026
The Extension Deadline is October 15, 2027, to file your Indiana Individual Income tax return. Indiana automatically grants a six-month extension without requiring separate extension forms. This is an extension to FILE, not an extension to PAY—payment is still due April 15, 2027.
What Indiana tax professionals need to know
Several key considerations make Indiana's tax landscape unique for 2026. Indiana's flat income tax system provides simplicity and competitive rates for businesses and Individuals. Electronic filing requirements continue to expand, and Indiana offers various business-friendly tax provisions.
Electronic filing requirements
Indiana has implemented electronic filing systems for taxpayers:
- C Corporations and pass-through entities should file electronically through INTIME
- Individuals can use Indiana's online system for free electronic filing
- Business deductions can be processed more efficiently through electronic systems
- Professional preparers must use approved software vendors
Indiana's unique tax features for 2026
3.23% flat rate on all Indiana taxable income
Indiana offers competitive rates with neighboring states through its flat tax structure.
Local income taxes imposed by counties
Each county may impose local income taxes with rates that vary significantly.
Economic Development for a Growing Economy (EDGE) credits
Indiana provides EDGE tax credits for qualifying business activities.
Research and development credits
Indiana offers R&D credits to support business innovation.
County Income Tax System
Indiana's county income tax system creates unique compliance considerations:
- Each county may impose local income taxes
- Rates vary significantly by county
- Individuals pay based on residence, not work location
- Businesses must withhold based on employee residence
Business-friendly environment
Indiana positions itself as a business-friendly state:
- Low flat Corporate income tax rate
- Competitive total tax burden
- Various economic development incentives
- Right-to-work state considerations
Business incentives and credits
Indiana provides various business tax incentives:
- Economic Development for a Growing Economy (EDGE) tax credits
- Research and development tax credits
- Hoosier Business Investment (HBI) tax credits
- Training and training (T&T) credits
Manufacturing considerations
Indiana has a significant manufacturing base:
- Manufacturing equipment sales tax exemptions
- Special provisions for manufacturing businesses
- Industrial development incentives
- Workforce development credits
Retirement income considerations
Indiana provides certain retirement income benefits:
- Military retirement pay exemptions may apply
- Social Security benefits are generally exempt from the Indiana state income tax
- Pension income considerations for residents
- Senior citizen tax benefits
Professional tax guidance
For complex Indiana tax situations, consulting with qualified tax professionals through an accounting firm directory can help ensure compliance and identify available tax-saving opportunities.
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The material discussed on this page is meant for general illustration and/or informational purposes only and is not to be construed as investment, tax, or legal advice. You must exercise your own independent professional judgment, recognizing that advice should not be based on unreasonable factual or legal assumptions or unreasonably rely upon representations of the client or others. Further, any advice you provide in connection with tax return preparation must comply in full with the requirements of IRS Circular 230.
Please note that if any due date falls on a federal or state holiday or weekend, it may be adjusted to the next business day. Always verify current deadlines with the appropriate tax professional and authorities.
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