What happens if I file my federal return after April 15?

If you owe tax and file after April 15 without an approved extension, the IRS assesses a failure-to-file penalty (5% of unpaid tax per month, up to 25%) plus a failure-to-pay penalty (0.5% per month) plus interest. If you're due a refund, there's no late-filing penalty — but you have only three years from the original deadline to claim it. CPAs should advise extension filers that an extension extends time to file, never time to pay.

Do state filing deadlines automatically follow federal?

Most states conform to the federal April 15 individual deadline, but conformity varies for corporate, pass-through, and franchise filings. Several states have unique deadlines: Louisiana (May 15), Virginia (May 1), Iowa (May 1 for individual), Delaware (April 30 for individual). Always verify against the state revenue department site — TaxScout links to the authoritative source on every state page.

Are estimated quarterly payments mandatory for CPA-firm clients?

Federally, individuals must pay estimated tax if they expect to owe $1,000 or more after withholding. C-corporations have a $500 threshold. Underpayment triggers Form 2210 / 2220 penalties calculated quarterly. Most CPA firms advise clients to safe-harbor at 100% of prior-year liability (110% for AGI over $150K) to avoid the penalty entirely.

Tax Year 2026 · Filed 2027State-revenue-department verified

Ohio tax deadlines 2026

Last updated May 13, 2026

Ohio individual income tax (Form IT-1040) conforms to the federal April 15 deadline.
Ohio Commercial Activity Tax (CAT) applies to businesses with $150,000+ in Ohio gross receipts — quarterly filings due 30 days after quarter-end.
Most Ohio municipalities levy a local income tax (typically 2-2.5%). Filed separately through CCA, RITA, or city-specific bureaus.

Ohio individual income tax (Form IT-1040)

Filing deadline

April 15, 2027

Extension deadline

October 15, 2027

Ohio individual rates range from 2.75% to 3.5% (TY2026). Automatic 6-month extension granted if federal Form 4868 is filed.

Quarterly payments

Q1 2026

Jan 1 – Mar 31, 2026

April 15, 2026

Q2 2026

Apr 1 – May 31, 2026

June 15, 2026

Q3 2026

Jun 1 – Aug 31, 2026

September 15, 2026

Q4 2026

Sep 1 – Dec 31, 2026

January 15, 2027

Authoritative source

Ohio Commercial Activity Tax (CAT)

CAT applies to entities with $150,000+ Ohio gross receipts. Quarterly returns due 30 days after each calendar quarter ends (April 30, July 31, Oct 31, Jan 31). $1.5M annual gross receipts threshold for liability above $150K registration.

Authoritative source

Ohio municipal income tax

Most Ohio cities + villages levy local income tax (typically 2-2.5%). Filed via CCA (Central Collection Agency), RITA (Regional Income Tax Agency), or directly with the municipality. Annual returns due April 15.

Authoritative source

Federal individual income tax (Form 1040)

Filing deadline

April 15, 2027

Extension deadline

October 15, 2027

Quarterly payments

Q1 2026

Jan 1 – Mar 31, 2026

April 15, 2026

Q2 2026

Apr 1 – May 31, 2026

June 15, 2026

Q3 2026

Jun 1 – Aug 31, 2026

September 15, 2026

Q4 2026

Sep 1 – Dec 31, 2026

January 15, 2027

Authoritative source

Authoritative resources

File these Ohio returns with confidence

TaxScout's tax form library walks through every IRS form CPA firms file for Ohio clients — who must file, key fields, common mistakes, and step-by-step instructions.

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Frequently Asked Questions

Ohio-specific and federal questions for tax year 2026.

Ohio CAT is a gross-receipts tax (not a net-income tax) levied on entities with Ohio-sourced gross receipts. Registration is required at $150,000+ gross receipts; tax liability begins at $1.5M. Rate is 0.26% on gross receipts above the threshold. Quarterly returns are due 30 days after each calendar quarter ends (Apr 30, Jul 31, Oct 31, Jan 31).

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