Every federal and California tax deadline a small business faces in 2026 — income returns, estimated payments, payroll filings, and sales tax — in one filterable list. Weekend and holiday shifts are already applied (which is why some land a day or two off the “normal” date). Filter to your entity, and add any deadline straight to your calendar.

    Notes that trip people up

    • Weekend & holiday shifts are applied. March 15, 2026 is a Sunday, so S-corp and partnership returns move to March 16; January 31 and October 31, 2026 are Saturdays, pushing those payroll/sales-tax filings to February 2 and November 2.
    • California estimated tax isn’t evenly split. Individuals pay on a 30% / 40% / 0% / 30% schedule (April 15, June 15, none in September, January 15) — not four equal quarters like the IRS. See FTB estimated tax.
    • The $800 minimum is unavoidable. LLCs, S-corps, and C-corps owe California’s $800 minimum tax even at a loss; the LLC version (Form 3522) is due the 15th day of the 4th month.
    • Extensions move the return, not the payment. Filing extensions push paperwork to September/October, but tax owed is still due in spring.
    Sources — government authorities only

    General information for calendar-year businesses, not tax advice for your situation. Fiscal-year filers, semi-weekly payroll depositors, monthly sales-tax filers, and businesses with prepayment obligations have additional or different dates. Always confirm against the agency links above, and talk to a CPA about your specific filing calendar.