For a calendar-year Delaware C-corp, the 2027 tax year runs on six anchor dates: February 1 (W-2s, Form 1099-NEC, Form 3921, the fourth-quarter Form 941 and Form 940, all moved from Sunday, January 31), March 1 (Delaware annual report and franchise tax), April 15 (Form 1120 for 2026 or a Form 7004 extension, plus the first 2027 estimated tax payment), June 15 and September 15 (estimated tax), October 15 (extended Form 1120) and December 15 (last estimated payment). Form 941 is also due April 30, August 2 and November 1. Three things changed for these filings: Form 1099-NEC is now only for contractors paid $2,000 or more in 2026, Section G of Form 6765 is required on 2026 R&D credit claims, and US companies no longer file BOI reports.
Add to your calendar (.ics file): every date below as an all-day event, each with its source link. It imports into Google Calendar, Outlook and Apple Calendar.
Dates come from the IRS's early-release draft of Publication 509 (2027), Tax Calendars, which already applies the weekend and holiday roll-overs, plus the form instructions and the Delaware Division of Corporations, all read on October 22, 2026. The final Publication 509 for 2027 was not out yet; we will check the dates against it when it is. Closing the 2026 books first? Use our year-end close checklist for SaaS startups; most of these filings need its outputs.
How the dates were worked out
When a federal due date falls on a Saturday, Sunday or legal holiday, the filing is on time if it is done the next day that is not one of those. "Legal holiday" means a legal holiday in the District of Columbia (Pub. 509 (2027) draft). In 2027 that moves five dates a calendar-year startup cares about:
- January 31 is a Sunday, so every "January 31" filing is due Monday, February 1.
- February 15 is Washington's Birthday, so the February 15 recipient date for some Forms 1099-MISC moves to Tuesday, February 16.
- February 28 is a Sunday, so paper information returns are due Monday, March 1.
- July 31 is a Saturday and October 31 a Sunday, so the second- and third-quarter Forms 941 are due Monday, August 2 and Monday, November 1.
None of the Delaware dates (March 1, June 1, June 30, September 1, December 1) falls on a weekend in 2027.
The 2027 calendar
| Date (2027) | What is due | Who | Source |
|---|---|---|---|
| Fri, Jan 15 | Fourth 2026 estimated tax payment for individuals (Form 1040-ES) | Founders with income not covered by withholding | Pub. 509 (2027) |
| Mon, Feb 1 | Form W-2 to employees; Forms W-2 and W-3 to the Social Security Administration | Any company with employees | W-2/W-3 instructions (2026) |
| Mon, Feb 1 | Form 1099-NEC to contractors and to the IRS, for nonemployees paid $2,000 or more in 2026 | Companies paying US contractors | 1099-MISC/NEC instructions (Rev. Dec 2026) |
| Mon, Feb 1 | Form 1099-MISC recipient copies (rent, other income and similar, $2,000 or more) | Companies with reportable payments | Pub. 509 (2027) |
| Mon, Feb 1 | Form 3921 to employees who exercised incentive stock options in 2026 | Companies with ISO exercises | Pub. 509 (2027) |
| Mon, Feb 1 | Form 941 for Q4 2026 and Form 940 (FUTA) for 2026. If every deposit was made on time and in full, you may file by Wed, Feb 10 | Employers | Pub. 509 (2027) |
| Tue, Feb 16 | Form 1099-MISC recipient copies with box 8 or box 10 (gross proceeds paid to an attorney) | Companies that paid settlement or attorney proceeds | Pub. 509 (2027) |
| Mon, Mar 1 | Delaware annual franchise tax report and franchise tax for 2026 ($50 filing fee) | Every Delaware corporation | Delaware Division of Corporations |
| Mon, Mar 1 | Paper Forms 1099-MISC and 3921 to the IRS, with Form 1096 | Paper filers (fewer than 10 information returns in total) | Pub. 509 (2027) |
| Wed, Mar 31 | Electronically filed Forms 1099-MISC and 3921 to the IRS | E-filers | Pub. 509 (2027) |
| Thu, Apr 15 | Form 1120 for 2026 and any tax due, or Form 7004 for an automatic 6-month extension (pay the estimated tax with it). Attach Form 6765 (R&D credit) and Form 5472 (if 25% foreign-owned) | Every C corporation | Pub. 509 (2027); Form 7004 instructions |
| Thu, Apr 15 | First 2027 corporate estimated tax installment | C corps expecting $500 or more of 2027 tax | Pub. 509 (2027); Form 1120 instructions |
| Fri, Apr 30 | Form 941 for Q1 2027 (May 10 if all deposits were on time); FUTA deposit if more than $500 is owed through March | Employers | Pub. 509 (2027) |
| Tue, Jun 1 | Delaware franchise tax installment: 40% of the 2027 estimate | Delaware corps whose 2027 tax will be $5,000 or more | 8 Del. C. § 504(a) |
| Tue, Jun 1 | Delaware LLC, LP or GP annual tax of $400 for 2026 | Delaware LLCs (a holding LLC, for example) | Delaware LLC/LP tax instructions |
| Tue, Jun 15 | Second 2027 corporate estimated tax installment | C corps expecting $500 or more of tax | Pub. 509 (2027) |
| Wed, Jun 30 | Delaware annual report for foreign corporations ($250) | Non-Delaware corporations registered in Delaware | Delaware Division of Corporations |
| Mon, Aug 2 | Form 941 for Q2 2027 (Aug 10 if all deposits were on time); FUTA deposit if more than $500 is owed through June | Employers | Pub. 509 (2027) |
| Wed, Sep 1 | Delaware franchise tax installment: 20% of the 2027 estimate | Delaware corps whose 2027 tax will be $5,000 or more | 8 Del. C. § 504(a) |
| Wed, Sep 15 | Third 2027 corporate estimated tax installment | C corps expecting $500 or more of tax | Pub. 509 (2027) |
| Fri, Oct 15 | Extended Form 1120 for 2026 (with Forms 6765 and 5472 if they apply) | C corps that filed Form 7004 by April 15 | Pub. 509 (2027) |
| Mon, Nov 1 | Form 941 for Q3 2027 (Nov 10 if all deposits were on time); FUTA deposit if more than $500 is owed through September | Employers | Pub. 509 (2027) |
| Wed, Dec 1 | Delaware franchise tax installment: 20% of the 2027 estimate | Delaware corps whose 2027 tax will be $5,000 or more | 8 Del. C. § 504(a) |
| Wed, Dec 15 | Fourth 2027 corporate estimated tax installment | C corps expecting $500 or more of tax | Pub. 509 (2027) |
Before the year starts there is one more: the fourth 2026 corporate estimated tax payment is due Tuesday, December 15, 2026. After it ends, the 2027 Forms W-2, 1099-NEC and the Q4 2027 Form 941 are due Monday, January 31, 2028.
Payroll tax deposits are not on this list
Form 941 is the quarterly return. The tax itself is deposited more often: by the 15th of the next month under the monthly schedule, or within days of each payroll under the semiweekly schedule. Your schedule depends on how much payroll tax you reported in the lookback period, and the dates are in IRS Publication 15. If you use a payroll provider, it makes these deposits and files Forms 941, 940 and W-2 for you; check that it does, and that your company is set up for the right states.
Federal filings in detail
Form 1120 and the extension
A corporation files Form 1120 by the 15th day of the 4th month after its tax year ends (Form 1120 instructions), so April 15, 2027 for calendar 2026. Form 7004 gives an automatic six months, to October 15, but it extends the time to file, not to pay: tax not paid by April 15 is charged a late-payment penalty of 1/2 of 1% a month (Form 7004 instructions). Many loss-making startups owe no federal income tax but still file, because the return records the losses they will use later and carries the R&D credit.
The 2026 return is the second one under Section 174A, which lets you deduct domestic R&D costs again instead of amortizing them over five years. If you chose to spread your unamortized 2022 to 2024 R&D costs over two years, the second half goes on this return. How that changes the tax and the cash plan is in our Section 174A guide.
Estimated tax
A corporation pays estimated tax in four installments, on the 15th day of the 4th, 6th, 9th and 12th months of its tax year, if it expects its tax for the year (after credits) to be $500 or more (Form 1120 instructions). A company with losses can usually skip them. A profitable one, or one whose R&D deduction no longer covers its income, should put the four dates in its cash forecast.
Form 5472 for foreign-owned startups
If one foreign person owns at least 25% of the vote or value of your US corporation, directly or indirectly, at any time in the year, you attach Form 5472 to Form 1120 by the return's due date, including extensions. The penalty for not filing it is $25,000 per form (Form 5472 instructions). This catches many companies with a founder or parent company outside the US.
Form 3921 for ISO exercises
Each employee who exercised incentive stock options during 2026 gets a Form 3921 by February 1. The IRS copy is due March 1 on paper or March 31 if filed electronically (Pub. 509 (2027) draft). Ask your cap table provider in January whether it prepares them.
Delaware dates
Every Delaware corporation files its annual franchise tax report and pays the tax by March 1 for the year before. The filing fee is $50 and the minimum tax is $175 under the Authorized Shares method or $400 under the Assumed Par Value Capital method; late filers pay a $200 penalty plus 1.5% interest a month (Delaware Division of Corporations, read October 22, 2026). If your current-year tax will be $5,000 or more, you prepay 40% on June 1, 20% on September 1 and 20% on December 1 (8 Del. C. § 504(a)). How to file, and why the notice often shows $85,165 when you owe $400, is in our Delaware annual report guide; the franchise tax calculator runs both methods.
California, if you have people or customers there
A Delaware corporation that is registered with California or doing business there files California Form 100. The return is due on the 15th day of the 4th month after year end (April 15, 2027), with an automatic extension to the 15th day of the 11th month (Monday, November 15, 2027) that does not extend the time to pay. Estimated payments are due on the 15th day of the 4th, 6th, 9th and 12th months, the same four dates as the federal ones. The minimum franchise tax is $800, but a corporation that incorporated or qualified through the California Secretary of State does not owe the minimum for its first taxable year (FTB 2025 Form 100 booklet and 2026 Form 100-ES, read October 22, 2026). Other states have their own rules; payroll in a state usually means registering there for withholding and unemployment tax. If you sell SaaS to California customers, note that SaaS becomes taxable there on January 1, 2027: see the California SaaS sales tax guide.
What changed for filings made in 2027
Form 1099-NEC threshold: $600 to $2,000
For payments made in 2026, you file Form 1099-NEC only for a contractor you paid $2,000 or more, up from $600. The same $2,000 now applies to most Form 1099-MISC boxes, such as rent and other income. The IRS instructions say the threshold "increased to $2,000 and may be adjusted for inflation beginning in calendar year 2027" (Instructions for Forms 1099-MISC and 1099-NEC, Rev. December 2026). Two things did not change: gross proceeds paid to an attorney are still reportable from $600, and the due date for Form 1099-NEC is still January 31 (February 1 in 2027) for both paper and electronic filing. If you file 10 or more information returns of all types in total, you must file them electronically.
We could not find an inflation-adjusted figure for 2027 payments on irs.gov as of October 22, 2026. It affects returns filed in January 2028, not this calendar.
Form 6765 Section G is now required
The R&D credit form has a Section G that asks for information by business component (each product, feature or process you spent qualified research money on). It was optional before. The instructions say: "For tax years beginning after 2025, Section G will be required." A calendar-2026 tax year began on January 1, 2026, so the 2026 Form 1120 you file in 2027 needs it, unless you are a qualified small business taking the payroll tax credit, or your qualified research expenses are $1.5 million or less, your average gross receipts for the prior three years are $50 million or less, and you claim the credit on an original return. If it applies, you report at least 80% of your qualified research expenses by business component, up to 50 components (Form 6765 instructions, Rev. December 2025).
If you take the payroll tax version of the credit as a qualified small business, the first exception covers you. Ask your R&D credit provider which version you claim, and start collecting the per-component numbers from your engineering records before the return is prepared (our year-end close checklist has the list). Our Form 6765 guide explains each Section G column, and the payroll credit starts in the first quarter after you file, so filing in March rather than on extension brings it forward.
BOI reports are over for US companies
FinCEN's beneficial ownership page now says "U.S. companies are exempt" and are "no longer required to file BOI reports". The final rule took effect on August 14, 2026 (fincen.gov/boi, read October 22, 2026). Reporting now applies only to companies formed outside the US that register to do business in a state. A Delaware C-corp has no BOI filing date in 2027. Who still files, and what to do about scam letters, is in our BOI reporting guide.
Dates that are not on the calendar but should be in your plan
- 83(b) elections: due "not later than 30 days after the date of such transfer" of restricted stock (26 U.S.C. § 83(b)(2)). It runs from each grant, not from a calendar date.
- 409A refresh: a 409A valuation is presumed reasonable for up to 12 months, or until a material event such as a new round. See our 409A provider comparison.
- State payroll and sales tax returns: due dates depend on the state and on your filing frequency.
- Founder personal returns: Form 1040 is due April 15, 2027, with personal estimated payments on April 15, June 15 and September 15, and the last 2027 installment in January 2028 (Pub. 509 (2027) draft).
FAQ
When are C corp taxes due in 2027?
A calendar-year C corporation files Form 1120 for 2026 and pays any tax by Thursday, April 15, 2027. With Form 7004 filed by that date, the return is due Friday, October 15, 2027, but the tax is still due April 15.
What is the Form 1120 extension due date for 2026 returns?
October 15, 2027, for a calendar-year corporation that files Form 7004 by April 15, 2027. The extension is automatic and six months long.
When are 1099-NEC forms due in 2027?
Monday, February 1, 2027, both to the contractor and to the IRS, because January 31 is a Sunday. You only need one for a contractor you paid $2,000 or more during 2026.
When is Delaware franchise tax due in 2027?
Monday, March 1, 2027, for the 2026 tax, together with the annual report. Delaware LLCs pay their $400 tax by Tuesday, June 1, 2027. Corporations owing $5,000 or more prepay on June 1, September 1 and December 1.
What are the 2027 estimated tax due dates for corporations?
April 15, June 15, September 15 and December 15, 2027 for a calendar-year corporation. None of them falls on a weekend or holiday in 2027.
Do startups still need to file a BOI report in 2027?
No, not if the company was formed in the US. FinCEN's final rule, effective August 14, 2026, exempts US companies. Only foreign-formed companies registered in a US state still report.
Dates and rules from IRS Publication 509 (2027, early-release draft), the IRS form instructions linked above, the Delaware Division of Corporations, Title 8 of the Delaware Code, the California Franchise Tax Board and FinCEN, all read on October 22, 2026. This page is general information, not tax or legal advice. Confirm your dates with your CPA, and check irs.gov for disaster-area extensions, which can move a deadline for companies in affected counties.
Taxes, Delaware fees and estimated payments are cash going out on known dates. Put them in your forecast next to payroll and runway with Adlega.