Why dates cost more than the math ever does
For most individual taxpayers, penalties and interest are driven by calendar mistakes, not math mistakes. The IRS and the state DORs calculate failure-to-file and failure-to-pay penalties daily, and they apply them to the wrong amount if you file late even if your numbers are right. The first half of staying out of trouble is knowing when each form is due.
A NOTE ON HOLIDAYS AND WEEKENDS
When a due date falls on a Saturday, Sunday, or federal holiday, the deadline slides to the next business day. The IRS publishes the official list each year in Notice 1239 (or its successor) and we keep that list close at hand. The table below shows the recurring date; consult the year-specific notice before treating it as final.
The federal calendar — every return and payroll marker on one wall
The table below consolidates every federal deadline we routinely handle for individual and small-business clients. Use it as a year-round checklist rather than a one-time read.
| Date | What's due | Notes |
|---|---|---|
| January 15 | Q4 estimated tax payment | Final quarter of the prior year. Pay any remaining federal individual or trust estimated tax for tax year N-1. |
| January 31 | W-2 and 1099-NEC / 1099-MISC to recipients | Employers must furnish wage statements and most 1099-NEC and 1099-MISC copies to the worker / contractor. Late or incorrect forms trigger $50+ per-statement penalties. |
| February 15 | Form W-4 re-certification reminder | No automatic deadline, but a useful mid-quarter landmark to recheck withholding if last year's return showed a balance due. |
| March 15 | S-corp and partnership return (Form 1120-S / 1065) | Calendar-year entities. Extension pushes this to September 15 (S-corp) or September 15 (partnership). K-1s must reach owners in time to file their 1040. |
| April 15 | Q1 estimated tax payment | First quarter of the current year for federal individual, trust, and certain corporation estimated taxes. |
| April 15 | Individual Form 1040 (no extension) | Calendar-year individual return and balance-due payment. Same day Form 1040-SR, Form 1040-NR (for nonresidents with U.S. income), and most trust returns Form 1041 are due. |
| April 15 | C-corp Form 1120 (calendar year) | Calendar-year corporation returns including any balance due. Extension to October 15 (Form 7004). |
| April 30 | Form 941 (Q1 payroll) | First-quarter federal payroll return. Small employers with 1-year zero-tax history get a few extra days to file in some years, but the deadline is generally the last day of the month. |
| June 15 | Q2 estimated tax payment | Second quarter of the current year for federal individual estimates. |
| July 31 | Form 941 (Q2 payroll) | Second-quarter federal payroll return. Same rules as April. |
| September 15 | Q3 estimated tax payment | Third quarter of the current year. Often the deadline that catches taxpayers who underpaid through April and June. |
| October 15 | Form 1040 (extension) | Extended individual return deadline. Most calendar-year individuals who filed Form 4868 by April 15 file here. Note: extension to file is NOT an extension to pay — interest and late-payment penalties accrue from April 15. |
| October 31 | Form 941 (Q3 payroll) | Third-quarter federal payroll return. |
| January 31 (following year) | Form 941 (Q4 payroll) | Fourth-quarter federal payroll return, combined with annual Form 940 (FUTA) on the same deadline. |
Quarterly estimates — the four dates most people forget
Most wage earners do not have to think about quarterly estimates because their employer withholds enough from each paycheck. But every taxpayer who falls into any group below should review these four dates every year and write a check (or schedule an IRS Direct Pay transfer) for each one.
- Self-employed individuals (sole proprietors, single-member LLCs) who expect to owe at least $1,000 after subtracting withholding and credits.
- Investors with significant dividends, interest, or capital gains that no employer is withholding against.
- Retirees who have chosen not to have withholding taken from Social Security, pension, or IRA distributions.
- Owners of pass-through entities (S-corp, partnership, multi-member LLC) who receive K-1 income not subject to employer withholding.
The safe-harbor rule — what it buys you, in plain English
You avoid the underpayment penalty if your withholding plus quarterly estimates add up to at least the smaller of (a) 90% of the current year's tax, or (b) 100% of the prior year's tax (110% if prior-year AGI was over $150,000). Many clients in our practice rely on the second prong because it is a fixed number and is easier to hit. The trade-off is that you may overpay during the year and get a refund next spring.
Filing extension is free. Payment extension is not.
Form 4868 buys you up to six additional months to file your federal Form 1040, moving the return deadline from April 15 to October 15. What confuses people is that the extension to file is not an extension to pay. The IRS still expects you to estimate and pay any balance due by April 15, and they will assess interest on any underpayment starting that day. The late-filing penalty (usually larger) only applies if you miss the October 15 deadline.
SMALL-BUSINESS ANGLE
The same rule applies to S-corp Form 1120-S, partnership Form 1065, and trust Form 1041 — the entity deadline can extend out (usually to September 15 or, with a second extension, March 31 of the following year) but the balance due still sits on the original date. Plan your cash flow accordingly.
North Carolina — same beat as federal, with a few local forms
North Carolina's Department of Revenue generally tracks the federal calendar for individual income tax. The North Carolina individual Form D-400 is due April 15, extended to October 15 with a request, and the four quarterly state estimates use the same April 15 / June 15 / September 15 / January 15 cadence as federal. Employer withholding returns align with federal payroll timing as a practical matter, even though NC's specific forms are different. Always confirm dates at ncdor.gov before treating them as final — figures and dates change yearly.
- NC individual Form D-400: April 15 (or October 15 with extension). Estimates follow the same federal quarterly dates.
- NC franchise tax: Due April 15 for calendar-year C-corporations and LLCs classified as corporations, with extensions available to a later date in the same year.
- NC sales & use tax: Monthly, quarterly, or annually based on liability.
Georgia — federal cadence, plus the 500 and 600S in the lead
Georgia's Department of Revenue also tracks the federal calendar for individual returns. Form GA 500 is due April 15 with an extension to October 15, and the four quarterly estimates use the same April / June / September / January cadence. Georgia's withholding and sales-tax returns have their own cadence that is similar to federal timing but uses Georgia-specific forms. Verify every date at dor.georgia.gov before treating them as final.
- GA Form 500: April 15 (or October 15 with extension). Estimates follow federal quarterly dates.
- GA Form 600S (corporate): April 15 for calendar-year corporations with extension options similar to federal.
- GA Form G-7 (withholding): Monthly or quarterly depending on withholding amount.
- GA sales-tax returns (ST-3 / ST-2): Monthly for larger vendors, quarterly / annually for smaller ones.
Four habits our NC and GA clients lean on, every year
- Put all four quarterly-estimate dates and the April 15 / October 15 individual dates on a recurring calendar at the start of every year — firm dates, not rolling reminders.
- Reconcile the year-to-date withholding against last year's total tax at each quarterly date so you are not surprised at the end of the year.
- If you have employees, set a recurring deadline one week ahead of each Form 941 / state-withholding date to gather payroll reports, then another to actually transmit.
- Confirm year-specific figures at irs.gov, ncdor.gov, and dor.georgia.gov each January. Dates and thresholds move every year and the schedule above is a general guide, not a year-specific filing calendar.
A NOTE ON FIGURES
Dates above describe the recurring federal cadence. Year-specific deadlines can shift — sometimes by a day, sometimes by a week when a holiday intervenes. NC and GA mostly follow the federal cadence but also publish their own year-specific calendars. Always cross-check current-year dates at the official sources before treating the schedule above as final.
Unsure which dates actually apply to your situation?
Book a free 15-minute consult — bring last year's return.