The founder's annual calendar

Most back-office deadlines are written as rules, not dates: the last day of the month after the quarter, the 15th day of the 4th month after the year ends. The date changes every year, and one more rule moves it whenever it lands on a weekend.

Northwind paid its first wages on September 25, 2026, in the third quarter. That starts its payroll calendar. A new employer is a monthly schedule depositorPayrollMonthly schedule depositorAn employer whose lookback-period tax was $50,000 or less, and every employer in its first year: the federal income tax withheld and both halves of FICA on a month's paydays are deposited by the 15th of the next month for its first calendar year, so the $2,335.20 owed on September's wages is deposited by October 15, 2026. The quarter's first Form 941PayrollForm 941The quarterly return of wages paid, federal income tax withheld and both halves of Social Security and Medicare tax, reconciled to the quarter's deposits. Due April 30, July 31, October 31 and January 31 — ten days later if every deposit was on time follows.

States add their own calendar to this one: withholding and unemployment returns wherever employees work, sales tax returns wherever the company is registered, and annual reports in each state it's qualified in. None of it is computed here, because each state sets its own rule, weekends included.

Where this goes next: the annual compliance calendarCompliance & tax · Lesson 10 of 10The annual compliance calendar, 2026–2027What are a startup's tax and compliance deadlines for the year?Northwind's 2026–2027 calendar computed from rules: the federal return, estimates, 1099s, Delaware's March 1, and the dates that follow events.9 min adds the dates that follow events, and Form 1120Compliance & tax · Lesson 3 of 10Form 1120: the federal return, the extension and the 21% rateWhen is Form 1120 due, and what does a startup C corp owe in federal income tax?The C corporation's federal return: due Apr 15, 2027 for a calendar year, 21% of taxable income, filed even in a loss year, and extended for filing only.10 min, corporate estimated taxCompliance & tax · Lesson 4 of 10Corporate estimated tax: four installments a yearDoes my C corp have to pay quarterly estimated taxes, and how much?Four installments a year once the tax reaches $500, each a quarter of the required annual payment, worked for Northwind's first full year.8 min and the 1099 deadlinesCompliance & tax · Lesson 8 of 10Information returns: 1099-NEC and 1099-MISCWhen are 1099-NEC and 1099-MISC due, and who gets one?The January information returns: who gets a 1099-NEC at $2,000 for 2026, and the 2027 dates, weekend moves included.7 min each get a lesson. On the payroll side, depositsPayroll · Lesson 4 of 8Payroll tax depositsWhen are payroll taxes due, and how do I deposit them?Northwind is a monthly depositor in its first year: September's $2,335.20 is due October 15, 2026, through EFTPS, before anything else is paid.12 min · 1 page, Form 941 line by linePayroll · In Payroll tax returns: 941, 940 and W-2Form 941, line by lineHow do I fill out Form 941?Northwind's Q3 2026 Form 941 from its register: $8,400 of wages, $2,335.20 of tax, nothing due.5 min and the year-end W-2sPayroll · Lesson 5 of 8Payroll tax returns: 941, 940 and W-2What payroll tax returns does an employer file, and when?Form 941 each quarter (Northwind's first by November 2, 2026), and Form 940 and the W-2s by February 1, 2027 — each tied to the register and the deposits.10 min · 1 page. The forecastFinance · In The 13-week cash flowPayroll and tax dates in the forecastWhen are payroll tax deposits due, and how do they go in a cash forecast?The IRS's monthly deposit schedule and the next-business-day rule, placed in Northwind's 13 weeks.5 min puts these dates into the cash plan.