Before you rely on this
Dates below are the standard statutory deadlines for calendar-year filers. Deadlines falling on a weekend or holiday shift to the next business day, fiscal-year filers follow a different schedule, and rules change. Treat this as a planning framework and confirm your own dates against IRS and New York State Department of Taxation and Finance guidance, or with your CPA, before acting.
Most businesses that miss a filing deadline did not forget it existed. They knew the date and started too late. A 15 March return needs the December close finished, the reconciliations complete and the K-1 information settled, work that has to begin in January, not in the first week of March.
So the useful version of a deadline calendar is not a list of dates. It is a list of dates with the lead time each one requires, which is what turns "we know it is due" into "we will make it".
First quarter: the heaviest
| Date | Obligation | Start work by |
|---|---|---|
| 15 Jan | Q4 federal and NYS estimated tax (individuals) | Early January, from Q3 projection |
| 31 Jan | W-2s to employees and SSA; 1099-NEC to recipients and IRS | Early December: verify addresses and W-9s before year end |
| 31 Jan | Q4 Form 941; annual Form 940 (FUTA) | Mid-January, after the final payroll posts |
| 28 Feb | Paper 1099 filing with the IRS (if not e-filing) | Early February |
| 2 Mar | Electronic 1099 filing with the IRS | Early February |
| 15 Mar | S corporation (1120-S) and partnership (1065) returns, federal and NYS; K-1s to owners | Mid-January: December close must be complete |
| 15 Mar | Extension (Form 7004) if the return will not be ready | Decide by end of February, not on the day |
| 20 Mar | NYS annual sales tax return (annual filers, year to 29 Feb) | Early March |
The 31 January information return deadline is the one most often underestimated. Chasing a missing W-9 from a contractor in the third week of January is a materially worse experience than collecting it before you pay their first invoice, and penalties for late or incorrect information returns apply per form, so a modest number of contractors becomes a real number quickly.
An extension extends the time to file. It does not extend the time to pay.
That distinction catches people out every year. If you extend and still owe, interest and late-payment penalties accrue from the original date. If an extension is likely, estimate the liability and pay it by the original deadline, which requires having a projection, which is the argument for doing the planning work in Q3.
Second quarter
| Date | Obligation | Start work by |
|---|---|---|
| 15 Apr | C corporation (1120) and individual (1040) returns, federal and NYS | Mid-February |
| 15 Apr | Q1 estimated tax (federal and NYS) | Early April, from current-year actuals |
| 30 Apr | Q1 Form 941; NYS quarterly withholding (NYS-45) | Mid-April |
| 15 May | Form 990 for calendar-year nonprofits; NYS CHAR500 | Early March: needs the audit or review finished |
| 15 Jun | Q2 estimated tax (federal and NYS) | Early June |
| 20 Jun | NYS quarterly sales tax (Mar–May period) | Early June |
For nonprofits the 15 May Form 990 date is deceptive, because a 990 cannot sensibly be completed before the audit or review is finished. Working backward: a mid-May filing needs fieldwork finished by late March, which needs readiness work done in January and February. Our New York nonprofit compliance guide works through the full sequence including CHAR500.
Third quarter, and the part that matters most
| Date | Obligation | Start work by |
|---|---|---|
| 31 Jul | Q2 Form 941; NYS-45; Form 5500 for calendar-year benefit plans | Mid-July; March if the plan requires an audit |
| 15 Sep | Extended S corporation and partnership returns | Mid-July: do not repeat March |
| 15 Sep | Q3 estimated tax (federal and NYS) | Early September |
| 20 Sep | NYS quarterly sales tax (Jun–Aug period) | Early September |
| Aug – Nov | The tax planning window | This is the quarter that changes the outcome |
That last row has no statutory deadline, which is exactly why it gets skipped, and it is the single highest-value item on this page.
By August you have eight months of actual results. A full-year projection built on that plus a forecast tells you the likely liability while there are still four months in which to do something about it: capital purchases and their depreciation treatment, owner compensation levels, retirement plan funding, timing of income and deductions, entity elections, and whether a structural change makes sense for next year.
By the time a return is being prepared in March, those levers are gone. The transactions already happened. A March conversation is a post-mortem; an October conversation is planning.
Fourth quarter
| Date | Obligation | Start work by |
|---|---|---|
| 15 Oct | Extended C corporation and individual returns | Mid-August |
| 31 Oct | Q3 Form 941; NYS-45 | Mid-October |
| 15 Nov | Extended Form 990 for nonprofits | September |
| 1 – 15 Dec | Execute agreed year-end planning actions | Decided in the Q3 window |
| 31 Dec | Hard stop for most year-end tax positions | Nothing after this date affects the year |
| Dec | Collect and verify W-9s for every contractor paid this year | Now, not in January |
The obligations with no fixed date
These vary by business and are the ones most likely to have no owner at all:
- Sales tax: New York assigns monthly, quarterly or annual frequency by volume, and reassigns it as you grow. Check your assigned frequency annually rather than assuming.
- Payroll tax deposits: semi-weekly or monthly depending on your lookback liability. The deposit schedule can change at the start of a calendar year.
- Multi-state filings: remote employees, out-of-state customers and third-party warehousing create obligations elsewhere, each with its own calendar.
- Annual reports and licenses: entity registrations, professional licenses and industry permits, most of which nobody owns until one lapses.
- Lender and covenant reporting, not a tax deadline, but it belongs on the same calendar because the consequence of missing it is more immediate.
Build the calendar once, properly
The version that works has four columns for every obligation: what is due, who owns it, when work starts, and current status. Visible to more than one person. A calendar that lives in one individual's inbox is not a compliance system. It is a single point of failure that happens to be working today.
If you would like the full 2026 calendar in a filterable format, it is on our resources page. And if the pattern of notices and near-misses suggests the problem is process rather than dates, managed tax compliance is the service that addresses it.