New York City Form NYC-EXT is the Application for Automatic Extension of Time to File Business Income Tax Returns, and any business that files a New York City corporate, unincorporated, or banking-corporation return with the NYC Department of Finance uses it to buy six extra months to file. Filing this single one-page form, paying the full tentative tax, and submitting before the original return deadline turns a stressful crunch into an automatic six-month grace period.
The form does not extend the time to pay — it only extends the time to file — and the difference between those two ideas is where most filers get tripped up. According to the NYC Department of Finance Annual Report, the City processes hundreds of thousands of business tax filings each year, and a meaningful share of late-filing penalties trace back to extensions that were filed on time but underpaid by even a dollar.
Here is what you will learn in this guide:
- 📋 Exactly which NYC business returns the NYC-EXT covers and which it does not
- 🧮 How to calculate your tentative tax so the extension stays valid
- 🖥️ How to file through NYC e-Services, by mail, and through approved software
- 💸 The penalties, interest, and consequences of an invalid extension under NYC Admin Code § 11-676 and § 11-687
- 📅 Three full filled-out NYC-EXT examples for the most common filer profiles
What Form NYC-EXT Is and Who Must File It
Form NYC-EXT is a one-page extension request filed with the NYC Department of Finance by any business that needs more time to file a New York City business income tax return. It grants an automatic six-month extension when the form is timely filed and the full tentative tax is paid by the original due date. The word “automatic” matters because the City does not approve or deny the form — it either accepts it as valid or treats it as void.
The form covers extensions for the Business Corporation Tax returns (NYC-2, NYC-2A, and NYC-2S), the older General Corporation Tax returns (NYC-3L, NYC-3A, NYC-4S, NYC-4S-EZ) used by S-corporations and certain holdovers, the Unincorporated Business Tax returns (NYC-202, NYC-202-EIN, NYC-204, NYC-204-EZ), and the Banking Corporation Tax returns (NYC-1, NYC-1A) for taxable years that still apply.
The City requires the form under NYC Admin Code § 11-655 for corporations and parallel provisions for UBT and banking returns. A separate form, NYC-EXT.1, exists for additional three-month extensions beyond the first six months and should not be confused with NYC-EXT. Pass-through entities filing only informational returns, sole proprietors who do not meet the UBT $95,000 gross-income threshold, and businesses with no NYC nexus do not file NYC-EXT.
The filer is usually the corporate officer, partner, member, or sole proprietor named on the return, or a paid preparer acting under a power of attorney. Marcus, a CPA preparing returns for a Bronx restaurant LLC, files NYC-EXT for his client because the books are not closed by March 15. Aisha, a freelance designer over the UBT threshold, files NYC-EXT herself online because her 1099s arrived late.
Before You Start: Documents and Information You Need
Filing NYC-EXT goes faster when you gather everything before you open the form. Missing a single number — like a prior-year overpayment credit — can void the extension or trigger a refund delay. Pull these items together first:
- Federal Employer Identification Number (EIN). The City matches your EIN to its taxpayer database; a typo routes the payment to the wrong account.
- Social Security Number (SSN). Sole proprietors filing NYC-202 use an SSN instead of an EIN, and entering the wrong one voids the extension.
- Business legal name and trade name (DBA). The legal name must match what is on file with the NYS Department of State.
- NYC business address and mailing address. A P.O. Box is allowed for mailing but not for the principal business address.
- Tax period beginning and ending dates. Calendar-year filers use 01/01/2025 through 12/31/2025; fiscal-year filers must enter the exact start and end.
- Type of return being extended. You must check exactly one box (NYC-2, NYC-202, NYC-204, etc.); checking two voids the form.
- Prior-year tax liability. Used as a safe harbor when calculating the tentative tax.
- Estimated current-year tax. Required to compute the tentative tax owed with the extension.
- Estimated tax payments already made. Quarterly Form NYC-400 or NYC-5UB payments reduce the balance due.
- Prior-year overpayment credited forward. This shows up on Line 2 and reduces the payment.
- Bank routing and account numbers. Required for ACH debit through NYC e-Services.
- Preparer’s PTIN, name, address, and phone. Required if a paid preparer signs the form.
If any item is missing, do not guess — pull the prior-year return, the NYC Department of Finance taxpayer account statement, or the federal Form 1120 to confirm the number.
Where to Get the Form and How to Access It
The current Form NYC-EXT lives on the NYC Department of Finance Business Tax Forms page and is updated each tax year, usually in December or January. The 2025 tax year version (filed in 2026) carries a revision date printed in the lower left corner of the form, and you should confirm the revision matches your tax year before filing.
You can download the fillable PDF of NYC-EXT directly, complete it on screen, and either print and mail it or upload it through NYC e-Services. Most approved tax software — including Intuit ProConnect, Drake, CCH Axcess, and Thomson Reuters UltraTax — also generates and e-files NYC-EXT as part of the federal extension package.
If you prefer paper, request a form by calling the NYC Department of Finance Business Taxpayer Assistance line at 311 or (212) NEW-YORK. Janet, a sole proprietor accountant, prefers paper because she keeps her own ink-signed copy in a binder. Carlos, a multi-state corporate tax director, e-files through CCH because it pushes the data straight from the federal Form 7004 worksheet.
The form itself is one page with about a dozen fields, but the instructions are a separate two- to four-page PDF that you should read before filling anything in. Always check the revision date in the footer; using last year’s form on this year’s filing causes the City to misroute your payment.
Step-by-Step: How to Fill Out NYC-EXT Line by Line
The form is organized into a header block, a return-type checkbox section, three numbered tax lines, a signature block, and a preparer block. Each part has its own quirks, and skipping a single box can void the extension.
Header: Tax Period Beginning and Ending
This pair of date boxes at the top of the form tells the City which tax year you are extending. The boxes ask you to enter the first and last day of your fiscal or calendar year in MM-DD-YY format.
To answer, write the start date on the left and the end date on the right, with no slashes. Calendar-year filers write 01-01-25 and 12-31-25 for the 2025 tax year. Marcus enters 07-01-25 and 06-30-26 for his client’s June fiscal year.
The most common edge case is a short tax year — for example, a corporation that dissolved mid-year. In that case, enter the actual short-period dates, not the full 12-month window. The most common mistake is leaving the dates blank because the form is “for an extension”; the City rejects undated forms outright. A widespread misconception is that calendar-year filers can skip these boxes — they cannot, and a blank header voids the extension.
Header: Name, Address, EIN, and Business Code
This block captures the filer’s identity. Enter the exact legal name as registered with the NYS Department of State, followed by the trade name (DBA) if different, the street address, city, state, ZIP, EIN, and the six-digit NAICS business code.
Use ALL CAPS, no punctuation in the name field, and no dashes in the EIN. ACME CONSULTING LLC, 123 BROADWAY, NEW YORK NY 10001, EIN 12-3456789 entered as 123456789. Aisha, the freelance designer, enters her SSN in the EIN box because she files NYC-202 as a sole proprietor.
The edge case that confuses filers most is the single-member LLC, which uses the member’s SSN if disregarded for federal tax but uses its own EIN for NYC UBT. The most common mistake is entering the trade name on the legal-name line, which causes the City to flag the account as a name mismatch. A misconception is that a P.O. Box is acceptable as the principal business address — it is not, though it is fine as the mailing address.
Return-Type Checkboxes
Below the header is a row of checkboxes that asks which return the extension covers. You must check exactly one box: NYC-2, NYC-2A, NYC-2S, NYC-3L, NYC-3A, NYC-4S, NYC-4S-EZ, NYC-202, NYC-202-EIN, NYC-204, NYC-204-EZ, NYC-1, or NYC-1A.
To answer, place an X or checkmark in the single box that matches your return type. Carlos checks the NYC-2A box because his client files a combined Business Corporation Tax return for an affiliated group.
The edge case is a filer who is unsure whether they owe Business Corporation Tax or General Corporation Tax — under NYC Admin Code § 11-653, C-corporations file NYC-2 and S-corporations still file NYC-3L or NYC-4S. The most common mistake is checking two boxes “to be safe,” which voids the form because the City cannot route the payment to two different tax accounts. A misconception is that checking NYC-2S covers any small corporation — NYC-2S is only for filers who meet specific gross-receipts and entity tests.
Line 1: Tentative Tax
Line 1 asks for the tentative tax — the filer’s best estimate of the full-year NYC tax liability for the period being extended. This number drives the entire extension because the City requires it to be paid in full.
To answer, calculate the estimated NYC tax under the same method you will use on the actual return (business income base, capital base, fixed dollar minimum, or alternative tax for UBT) and write the dollar amount with no cents. Marcus’s restaurant client expects $14,500 of UBT, so he writes 14500 on Line 1. Aisha estimates $1,800 in UBT and writes 1800.
The edge case is the fixed dollar minimum (FDM) filer — a corporation with little or no income still owes the FDM under NYC Admin Code § 11-654(1)(E), and that FDM amount goes on Line 1. The most common mistake is entering zero because the filer “expects a refund” — under-paying tentative tax voids the extension and triggers retroactive late-filing penalties. A misconception is that you can use last year’s tax as a safe harbor for the extension; for NYC-EXT, the rule is properly estimated current-year tax, not prior-year safe harbor.
Line 2: Payments and Credits
Line 2 captures everything already paid or credited toward the current year’s tax: estimated tax payments made on Form NYC-400 or NYC-5UB, prior-year overpayments credited forward, and any MTA surcharge or composite payments.
To answer, add up the four quarterly estimated payments and the prior-year credit, and enter the total. Marcus’s client made $3,000 in quarterly payments and had a $500 prior-year credit, so Line 2 is 3500. Aisha made no estimated payments, so she writes 0.
The edge case is a combined group — only the designated agent’s payments count on Line 2, not payments mistakenly remitted under a subsidiary’s EIN. The most common mistake is double-counting a prior-year overpayment that was already refunded by check, which inflates Line 2 and short-pays Line 3. A misconception is that federal estimated payments count toward the NYC line — they do not; only payments to the NYC Department of Finance appear on Line 2.
Line 3: Balance Due
Line 3 is Line 1 minus Line 2 — the payment that must accompany the extension. If the result is zero or less, Line 3 is zero, but the form still must be filed.
To answer, subtract Line 2 from Line 1 and enter the result. If Line 1 is $14,500 and Line 2 is $3,500, Line 3 is 11000 and Marcus’s client must remit $11,000 with the extension. Aisha’s Line 3 is 1800 because she made no prior payments.
The edge case is a filer with excess payments (Line 2 greater than Line 1) — the form is still required, but no payment accompanies it, and the excess flows through to the actual return when filed. The most common mistake is rounding cents inconsistently, which causes a one-dollar underpayment that invalidates the extension under NYC Admin Code § 11-687(g). A misconception is that paying most of the tax is good enough — the statute requires the full properly estimated tax, not “substantially all.”
Signature Block
The signature block requires an officer, partner, member, or sole proprietor to sign and date the form, along with their printed name, title, phone number, and email. Paid preparers also sign in a separate preparer block below.
To answer, sign in ink (paper) or apply an e-signature (e-file), date the form with the date of submission in MM-DD-YY format, and print the signer’s name and title. Janet signs as Janet Greene, Sole Proprietor, 03-14-26. Carlos’s CFO signs as Lin Park, Chief Financial Officer.
The edge case is a deceased or incapacitated signer — a court-appointed fiduciary signs and attaches Letters Testamentary. The most common mistake is signing without a title, which the City treats as an unsigned form. A misconception is that an outside accountant can sign for the taxpayer — only an officer or a preparer with a Form POA-1 can sign for the entity.
Preparer Block
If a paid preparer completed the form, the preparer’s name, PTIN, firm name, address, and phone go in the bottom block, along with the preparer’s signature and date.
To answer, the preparer enters their full name, PTIN beginning with P followed by eight digits, firm EIN, and a daytime phone. Marcus enters Marcus Reyes, CPA, PTIN P01234567, firm Reyes Tax LLC.
The edge case is a non-paid preparer (a relative or in-house bookkeeper not paid for tax work) — they leave the preparer block blank. The most common mistake is leaving the PTIN off when the preparer is paid, which violates IRS Circular 230 § 10.50 and triggers City correspondence. A misconception is that the preparer signature substitutes for the taxpayer signature — both are required when a paid preparer is involved.
Three Filled-Out Examples Using Real Scenarios
These three scenarios walk through the most common NYC-EXT filer profiles. Each uses concrete numbers and entity facts so you can compare them to your own situation.
Scenario 1: Marcus, CPA Filing NYC-204 for a Restaurant LLC
Marcus prepares the extension for Bronx Bistro LLC, a two-partner restaurant on Arthur Avenue with calendar-year UBT filings. The books are not closed by March 15 because the POS vendor is late delivering Q4 reports.
| Form Section | What Marcus Enters |
|---|---|
| Tax Period Beginning / Ending | 01-01-25 / 12-31-25 |
| Legal Name | BRONX BISTRO LLC |
| Address | 2350 ARTHUR AVE, BRONX NY 10458 |
| EIN | 87-6543210 entered as 876543210 |
| Return Type Checkbox | NYC-204 |
| Line 1 Tentative Tax | 14500 |
| Line 2 Payments and Credits | 3500 |
| Line 3 Balance Due | 11000 |
| Signature Block | Marcus Reyes, Managing Partner, 03-14-26 |
| Preparer Block | Reyes Tax LLC, PTIN P01234567 |
Scenario 2: Aisha, Freelance Designer Filing NYC-202
Aisha is a sole proprietor graphic designer in Brooklyn whose 2025 gross income was $112,000, putting her over the $95,000 UBT threshold. She files NYC-EXT online through e-Services because her 1099s arrived in late March.
| Form Section | What Aisha Enters |
|---|---|
| Tax Period Beginning / Ending | 01-01-25 / 12-31-25 |
| Legal Name | AISHA WILLIAMS |
| Trade Name | AISHA WILLIAMS DESIGN |
| Address | 742 BERGEN ST, BROOKLYN NY 11238 |
| SSN (in EIN box) | 123-45-6789 entered as 123456789 |
| Return Type Checkbox | NYC-202 |
| Line 1 Tentative Tax | 1800 |
| Line 2 Payments and Credits | 0 |
| Line 3 Balance Due | 1800 |
| Signature Block | Aisha Williams, Sole Proprietor, 04-12-26 |
Scenario 3: Carlos, Tax Director Filing NYC-2A for a Combined Group
Carlos is the tax director at a Manhattan ad-tech company, Pixel Bridge Inc., parent of a three-entity combined group filing NYC-2A under the Business Corporation Tax.
| Form Section | What Carlos Enters |
|---|---|
| Tax Period Beginning / Ending | 01-01-25 / 12-31-25 |
| Legal Name | PIXEL BRIDGE INC |
| Address | 55 WATER ST, NEW YORK NY 10041 |
| EIN | 13-9876543 entered as 139876543 |
| Return Type Checkbox | NYC-2A |
| Line 1 Tentative Tax | 425000 |
| Line 2 Payments and Credits | 380000 |
| Line 3 Balance Due | 45000 |
| Signature Block | Lin Park, CFO, 04-10-26 |
| Preparer Block | Carlos Mendez, PTIN P09876543, CCH Axcess |
How to File the Completed Form
NYC-EXT can be filed three ways, and the channel you pick controls when payment posts and what proof you keep. Pick the channel that gets the form and the payment to the City before midnight of the original due date.
Online through NYC e-Services. Log in at the NYC e-Services portal, choose “File an Extension,” enter the form data on screen, and pay by ACH debit from a checking or savings account. There is no fee. Processing is real-time, and you receive an electronic confirmation number within seconds — save it as your proof of filing.
By mail with a check or money order. Mail the signed form and payment to NYC Department of Finance, P.O. Box 3933, New York, NY 10008-3933. Make the check payable to NYC Department of Finance, write the EIN and “NYC-EXT 2025” in the memo line, and use certified mail with return receipt as your proof of filing. Allow 7–10 days for the check to clear.
Through approved tax software. Preparers using software listed on the NYC DOF approved e-file vendors page can transmit NYC-EXT alongside the federal Form 7004. The software returns an acknowledgment within 24–48 hours; keep that acknowledgment as proof of filing.
Payment methods accepted are ACH debit, ACH credit (initiated from your bank), check, money order, and — for amounts under $20,000 — credit card through Pay.gov, which charges a 2.49% convenience fee. Carlos’s $45,000 balance must go ACH because credit cards are capped. Aisha’s $1,800 goes through e-Services ACH for free.
What Happens After You File
Once the City accepts NYC-EXT and the full tentative tax posts, your filing deadline moves six months out. A March 15 deadline becomes September 15; an April 15 deadline becomes October 15. No paper approval letter is mailed — silence from the NYC Department of Finance is the approval.
If the payment is short or the form is late, the City voids the extension retroactively. You will receive a Notice of Tax Due assessing the late-filing penalty (5% per month, capped at 25%), the late-payment penalty (0.5% per month), and interest at the rate published quarterly in the NYC DOF Interest Rates Memorandum. Interest compounds daily.
You can check your account status anytime in NYC e-Services under “Account Activity.” The payment shows as posted within 1–3 business days for ACH and 7–10 days for mailed checks. If you discover a shortfall before the original due date, file a second NYC-EXT or remit the difference as an estimated payment — do not wait for the City to bill you.
When you file the actual return six months later, attach a copy of the NYC-EXT confirmation and report the Line 3 payment as a credit on the corresponding line of NYC-2, NYC-202, NYC-204, or whichever return type you checked.
Mistakes to Avoid When Filling Out the Form
Each NYC-EXT field is a tripwire. These are the errors that most often turn a routine extension into a penalty notice:
- Underpaying the tentative tax by even one dollar — voids the extension and triggers retroactive late-filing penalties under § 11-687.
- Checking two return-type boxes — the City cannot route the payment, so the form is rejected.
- Leaving the tax period dates blank — undated forms are voided automatically.
- Using last year’s form revision — the payment routes to the prior tax year’s account.
- Entering a trade name on the legal-name line — flags a name-mismatch hold.
- Signing without a title — treated as an unsigned form.
- Forgetting the PTIN when a paid preparer signs — triggers a Circular 230 inquiry.
- Mailing without certified return receipt — leaves you with no proof of timely filing.
- Paying by credit card over $20,000 — Pay.gov rejects, and the deadline passes.
- Filing NYC-EXT.1 instead of NYC-EXT — NYC-EXT.1 is for the additional extension, not the first.
- Ignoring the fixed dollar minimum — corporations with no income still owe FDM and must include it on Line 1.
- Counting federal estimated payments on Line 2 — only NYC payments count.
Do’s and Don’ts
Do confirm your EIN on the IRS EIN verification letter before filing — a typo routes the payment to the wrong account.
Do file electronically through NYC e-Services — it produces a real-time confirmation that mailed forms cannot match.
Do pay the tentative tax in full, even if you expect a refund — the safe harbor is properly estimated current-year tax, not prior-year tax.
Do save the confirmation number or certified-mail receipt for at least three years — the City can audit the extension’s timeliness.
Do file NYC-EXT even when Line 3 is zero — the form is still required to start the six-month clock.
Do match the legal name to the NYS Department of State record exactly.
Don’t assume the extension is approved — the City notifies you only when it is rejected, so absence of mail is not proof.
Don’t wait until the deadline day to file by mail — mailroom delays at P.O. Box 3933 can post payments late.
Don’t mix tax years in one filing — each tax year requires its own NYC-EXT.
Don’t confuse NYC-EXT with federal Form 7004 or NYS Form CT-5 — each jurisdiction requires its own extension.
Don’t sign on behalf of the taxpayer without a Form POA-1 on file.
Don’t leave the preparer block blank if you were paid — it violates Circular 230.
Pros and Cons of Filing on Your Own vs. With Help
Pros of filing pro se (yourself).
- No preparer fee — the NYC e-Services portal is free.
- Full control of timing — you file the moment your numbers are ready.
- Immediate confirmation — e-Services issues a confirmation in seconds.
- Direct account access — you see your payment post in real time.
- Builds tax literacy — repeated DIY filings teach you the underlying rules.
Cons of filing pro se.
- Higher error risk — a one-dollar underpayment voids the extension.
- No professional review — nobody catches the missed FDM or the wrong return-type box.
- Time cost — gathering payments and credits eats hours during peak season.
- No representation if audited — only an enrolled preparer or attorney can argue penalties down.
- Software gaps — DIY filers rarely use software that pre-fills NYC-EXT from the federal extension.
Pros and Cons of Online vs. Paper Filing
| Factor | Online (NYC e-Services) | Paper (Mail) |
|---|---|---|
| Cost | Free | Cost of certified mail (~$5) |
| Confirmation speed | Real-time | 7–10 days for check to clear |
| Proof of filing | Confirmation number | Certified mail receipt |
| Payment options | ACH debit only (free) | Check, money order |
| Risk of misrouting | Very low | Higher (P.O. Box delays) |
| Best for | Most filers | Filers without a bank account on file |
FAQs
Is NYC-EXT the same as the federal Form 7004?
No. Federal Form 7004 extends federal returns. NYC-EXT extends only NYC business tax returns. You must file both separately to extend each jurisdiction.
Does NYC-EXT also extend my New York State return?
No. New York State Form CT-5 extends State corporate returns. NYC-EXT covers only City returns. File CT-5 with the State separately.
Do I have to pay anything if I expect a refund?
Yes. You must still file NYC-EXT with Line 3 showing zero, because the form itself starts the six-month extension clock and protects against late-filing penalties.
Can I file NYC-EXT after the original due date?
No. A late NYC-EXT is invalid. The form must be filed and the tax paid on or before the original return due date for the extension to apply.
What if I write the wrong EIN in the EIN box?
No extension is granted to your account because the payment routes to the wrong taxpayer file. Call 311 immediately to request a payment transfer and refile.
Do I check NYC-2 or NYC-2S in the return-type box for a small C-corp?
No single answer fits all — NYC-2S is only for corporations meeting the gross-receipts and entity tests in the NYC-2S instructions. Most C-corps check NYC-2.
If Line 1 equals Line 2, do I still file?
Yes. Line 3 is zero, but the form is still required. Without it, the City has no record of an extension request.
Can a single-member LLC use the owner’s SSN on NYC-EXT?
No — for NYC UBT purposes, a single-member LLC uses its own EIN, even if it is a disregarded entity for federal tax. Only a true sole proprietor uses an SSN.
How long does the extension last?
Yes, six months — automatic from the original due date. A second three-month extension requires Form NYC-EXT.1 and is not automatic.
Do I attach NYC-EXT to my final return?
No, you do not attach the form itself, but you do report the Line 3 payment as a credit on the corresponding line of the actual return.
Can a paid preparer sign Line 9 instead of the taxpayer?
No. The taxpayer or an officer must sign the taxpayer signature line. The preparer signs the separate preparer block.
What happens if my Line 1 estimate is too low?
No valid extension exists if the underpayment is material. The City voids the extension and assesses late-filing penalties from the original due date under § 11-687.
Can I pay NYC-EXT by credit card?
Yes, through Pay.gov for amounts under $20,000, with a 2.49% convenience fee. Larger balances must go by ACH or check.
Do estimated tax payments on Form NYC-400 count on Line 2?
Yes. All quarterly NYC-400 estimated payments made for the tax year being extended are included on Line 2, along with prior-year credits.
Related reading
- How to Fill Out New York Form CT-5 (w/Examples) + FAQs
- How to Fill Out New York Form ST-810 (w/Examples) + FAQs
- How to Fill Out New York Form NYC-2 (w/Examples) + FAQs
- How to Fill Out New York Form NYC-202 (w/Examples) + FAQs
- How to Fill Out New York Form NYC-2A (w/Examples) + FAQs
- How to Fill Out New York Form NYC-3L (w/Examples) + FAQs
- How to Fill Out New York Form IT-558 (w/Examples) + FAQs