What is a Tax filing deadline?

A tax filing deadline is the final date established by the IRS or state tax authority by which taxpayers must submit their tax returns and pay any taxes owed to avoid late filing penalties and interest charges. The primary federal deadline for Individual taxpayers is April 15 each year, covering the previous year's income and deductions. Business entities face varying deadlines based on their structure, with partnerships and S Corporations typically due in mid-March and C Corporations due in mid-April. Taxpayers can request automatic extensions using Form 4868 or Form 7004 that provide additional time to file returns, though extensions do not extend payment deadlines for taxes owed. Meeting tax filing deadlines maintains compliance with tax laws and prevents the accumulation of costly penalties and interest charges. The 2026 California State Tax Deadlines and other state-specific dates help coordinate federal and state compliance requirements efficiently.

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