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

North Carolina tax deadlines 2026

Last updated May 13, 2026

North Carolina adopted a flat 4.5% individual income tax for 2026 (continuing phased reduction from 4.75% in 2025).
Form D-400 (individual return) conforms to the federal April 15 deadline. Automatic 6-month extension via Form D-410.
NC Pass-Through Entity Tax (PTET) election available at 4.5% for S-corps and partnerships — SALT cap workaround.

North Carolina individual income tax (Form D-400)

Filing deadline

April 15, 2027

Extension deadline

October 15, 2027

NC 2026 flat rate: 4.5% (phased reduction continues to 3.99% by 2027 subject to revenue triggers).

Extension: File Form D-410 by April 15 for automatic 6-month extension; tax payment still due April 15.

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

NC Pass-Through Entity Tax (PTET)

Filing deadline

April 15, 2027

PTET election made annually on Form CD-419. Entity-level tax at 4.5% provides federal SALT cap workaround. Estimated quarterly PTET payments aligned with federal estimated dates.

Authoritative source

NC franchise tax (corporations)

Filing deadline

April 15, 2027

$200 minimum franchise tax on all corporations doing business in NC. Filed with corporate income tax return (Form CD-405).

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 North Carolina returns with confidence

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

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Frequently Asked Questions

North Carolina-specific and federal questions for tax year 2026.

The NC Pass-Through Entity Tax (PTET) election lets partnerships and S-corps elect to pay 4.5% North Carolina income tax at the entity level — creating a federal SALT cap workaround. The election is made annually on Form CD-419 with the entity's NC return. Estimated quarterly PTET payments align with federal estimated tax dates.

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