Business Tax Deadlines

Quarterly estimated taxes

• Q1 — April 15
• Q2 — June 15
• Q3 — September 15
• Q4 — January 15 of the following year

Income tax return deadlines

• S-Corp (1120-S) and partnership (1065) — March 15
• Sole prop / single-member LLC (Schedule C with 1040) — April 15
• C-Corp (1120) — April 15 (calendar-year)
• Extension to September 15 (1120-S, 1065) or October 15 (1040, 1120)

Payroll and information returns

• W-2s to employees and SSA — January 31
• 1099-NEC to contractors and IRS — January 31
• Form 941 — last day of the month after each quarter (Apr 30, Jul 31, Oct 31, Jan 31)
• Form 940 (FUTA) — January 31
• Federal payroll tax deposits — semi-weekly or monthly per your schedule

State and local

State income, sales tax, franchise tax, and local business license filings have their own calendars. Pull yours from your state's Department of Revenue and add them to the same calendar so nothing falls through.

Penalty math (why late is expensive)

• Late filing — 5% per month, up to 25% of unpaid tax
• Late payment — 0.5% per month plus interest
• Late 1099-NEC — $60 to $310 per form, depending on lateness
• Late 1120-S / 1065 — $245 per partner/shareholder per month