2027 Ohio Tax Deadlines

Last updated: August 5, 2026

Key Ohio tax dates at a glance

• April 15, 2027: First Individual estimated payment and first pass-through entity estimated payment.
• June 15, 2027: Second estimated payment.
• September 15, 2027: Third estimated payment.
• January 18, 2028: Fourth Individual estimated payment.
• April 18, 2028: Calendar-year IT 1140, IT 4708, and IT 4738 pass-through entity returns and payments.
• April 18, 2028: Calendar-year Individual income tax and school district income tax returns and payments.
• May 10, 2028: First-quarter 2028 Commercial Activity Tax return and payment for quarterly CAT filers.
• September 15, 2028: Extended IT 1140 return, file only.
• October 16, 2028: Extended Individual, IT 4708, and IT 4738 returns, file only.

When are Ohio taxes due in 2027?

Ohio 2027 calendar-year Individual returns are generally due April 18, 2028, and many pass-through entity returns are due April 18, 2028. Ohio has no traditional corporate income tax, so business teams should track Commercial Activity Tax quarterly instead of treating CAT as a C Corporation income-tax return.

When is the Ohio C Corporation return due?

Ohio C Corporations should plan around May 10, 2028, for the first-quarter 2028 CAT return; Ohio does not impose a traditional corporate income tax for the calendar-year corporate-facing return, tax, or business-level filing noted in this page.

• CAT quarterly returns at a rate of 0.26% are required when taxable Ohio gross receipts exceed the $6 million CAT exclusion threshold.
• File and pay through Ohio OH|TAX.

What are Ohio C Corporation extension rules?

The extended filing deadline for the main calendar-year Ohio corporate-facing return is May 10, 2028. The extension is to file only, and tax or required payments remain due by May 10, 2028, for the first-quarter 2028 CAT return; Ohio does not impose a traditional corporate income tax.

When are Ohio S Corporation and Partnership returns due?

Ohio S Corporations should plan around April 18, 2028, and Partnerships should plan around April 18, 2028.

Which Ohio pass-through forms are required?

Use the applicable Ohio pass-through return and related payment or owner-reporting forms for the entity type and election facts.

• IT 1140: Pass-Through Entity and Trust Withholding Tax Return.
• IT 4708: Pass-Through Entity Composite Income Tax Return.
• IT 4738: Electing Pass-Through Entity Income Tax Return.
• IT 1140, IT 4708, or IT 4738, depending on withholding, composite, and election facts.

What are Ohio pass-through extension rules?

The extended filing deadline for calendar-year Ohio S Corporation and Partnership returns is September 15, 2028, or October 16, 2028, depending on the Ohio pass-through return type. The extension is to file only, so tax, withholding, composite, or entity-level payments should be handled by the original deadline.

When is the Ohio Individual income tax return due?

Calendar-year Ohio Individual income tax returns and payments are due April 18, 2028.

• IT 1040: Ohio Individual Income Tax Return.
• SD 100: School District Income Tax Return when required.
• IT 1040ES: Individual estimated payment voucher.

What Ohio Individual rate and residency issues should be checked?

Tax year 2027 Individual instructions should be checked for final rate tables, standard deductions or exemptions, residency rules, retirement-income treatment, credits, estimated-payment thresholds, and any filing-year changes specific to Ohio.

When are Ohio estimated payments due?

Ohio estimated-payment work should distinguish Individual payments, pass-through entity payments, school district tax, municipal net profits tax, and CAT.

• April 15, 2027: First estimated payment.
• June 15, 2027: Second estimated payment.
• September 15, 2027: Third estimated payment.
• January 18, 2028: Fourth Individual estimated payment.

Who must make Ohio estimated payments?

Taxpayers should use the final 2027 Ohio instructions to confirm estimated-payment thresholds, safe-harbor rules, credits, withholding, pass-through owner treatment, and electronic-payment requirements.

What are Ohio extension deadlines?

Ohio extension deadlines are September 15, 2028, or October 16, 2028, depending on the Ohio pass-through return type for pass-through filings, May 10, 2028, for corporate-facing filings, and October 16, 2028, for Individual returns. Extensions add filing time only; payment deadlines remain tied to the original return due dates.

What Ohio-specific rules should tax professionals watch for 2027?

Beyond the core return deadlines, Ohio tax professionals should track state-specific rate, credit, local-tax, industry, and filing-method rules before the 2027 season locks.

• Ohio does not impose a traditional corporate income tax, but C Corporations and other businesses may still have Commercial Activity Tax exposure when taxable Ohio gross receipts exceed the $6 million exclusion threshold.
• CAT annual and quarterly due dates are separate from Ohio Individual and pass-through income-tax deadlines.
• Ohio CAT returns and many state tax filings are handled electronically through the Ohio Business Gateway or Ohio e-file workflows.
• Municipal income tax and municipal net profits tax can create city-level filing work outside the state return, with local rates often ranging from 0.5% to 3.0% and reciprocity agreements affecting credit calculations.
• School district income tax may require SD 100 filing for affected Individuals.
• Pass-through entity owners should review IT 1140 withholding, IT 4708 composite filing, and IT 4738 electing PTE rules before filing.
• Manufacturing, logistics, research, job-creation, and municipal incentive issues should be reviewed by location.
• Agriculture and CAUV property-tax treatment, energy incentives, renewable-energy development, and local property-tax issues can affect Ohio clients outside the income-tax return.

Instead AI helps tax teams treat Ohio due dates as operational work, not a static checklist.

Tax-professional context: Ohio's tax landscape has several features that set it apart and shape planning for tax year 2027. Ohio does not levy a traditional corporate income tax; instead it applies the Commercial Activity Tax (CAT) to gross receipts, uses a graduated individual income tax that has been flattening, and layers municipal income taxes on top of the state return. Confirm current-year rates, thresholds, and e-filing rules in the final 2027 Ohio instructions.

Electronic filing requirements:

• CAT returns must be filed/paid electronically through the Ohio Business Gateway.
• Individuals can file/pay through OH|TAX eServices.
• Preparers must use Ohio-approved software vendors.

Business Tax Credits:

• Job Creation Tax Credit; Ohio Historic Preservation Credit; Motion Picture Credit; R and D Investment Loan Program; Small Business Investor Income Deduction.

Retirement income considerations:

• Military retirement pay may be exempt; Social Security generally exempt; pension/senior credits may apply — confirm eligibility in 2027 instructions.

Ohio's Commercial Activity Tax and municipal income taxes replace a corporate income-tax calendar, so firms can find specialists through the accounting firm directory.

What sources support these Ohio dates?

• Ohio IT 1040 instructions.
• Ohio IT 1140 instructions.
• Ohio IT 4708 instructions.
• Ohio Small Business Tax Guide.

Run Ohio CAT, PTE, and local deadline checks

Instead's AI-driven tax platform helps Ohio teams coordinate return work, payment review, extensions, and filing follow-through before deadlines move from planning to execution.

For Ohio practices, integrations, Firm Agent, and research help connect research, planning, and operational handoffs without duplicating deadline data. Built for tax professionals who want source-backed state deadline control across clients, entities, and reviewer workflows.