S-Corp Deadlines Calendar: Key Filing & Tax Dates

Running an S-corp means juggling business filings, owner payroll, and personal estimated taxes at the same time. When deadlines sneak up, owners often pay themselves inconsistently, under-reserve for taxes, or miss quarterly estimates. A calendar lets you plan owner pay, distributions, and tax reserves with the year in mind — which is exactly what the S-corp salary calculator is designed to support.

• Form 1120-S (S-corp return) — generally due March 15 for calendar-year S-corps, with a 6-month extension available.
• Schedule K-1 to shareholders — issued with the 1120-S so owners can file their personal return.
• Personal Form 1040 — generally due April 15 for individuals.
• Quarterly estimated taxes — typically April, June, September, and January for the prior year's Q4.
• W-2 and 1099-NEC forms — generally due to recipients and the IRS by January 31.
• Payroll tax deposits and quarterly Form 941 filings tied to owner salary.

Specific dates can shift due to weekends, holidays, or IRS announcements. Always confirm the current year's dates with the IRS or a licensed professional.

Solo S-corp owners usually owe estimated taxes personally, since K-1 income flows through to the 1040. Many owners use a quarterly reserve approach to avoid surprises. The quarterly tax planner can help you think through what to set aside each quarter.

If you take a reasonable salary as an S-corp owner, you'll typically have payroll tax deposit deadlines and quarterly Form 941 filings. Most owners use a payroll provider to handle these, but you still want them on your calendar so owner pay timing stays consistent.

• Confirm year-to-date salary vs. plan and adjust if needed before payroll closes.
• Check that distributions taken match your records and are reasonable vs. salary.
• Review tax reserves vs. expected liability before Q4 estimates.
• Prepare W-2 (for owner salary) and any 1099s for contractors.

• Treating the personal 1040 deadline as the only date that matters.
• Skipping quarterly estimates and trying to catch up at year-end.
• Adjusting owner salary in December without thinking about payroll filings.
• Forgetting that an S-corp extension extends the filing date, not payment dates.