Delaware Business Tax Extension LLC / Partnership – S Corporation – C Corporation – Fiduciary / Estate / Trust
Connect with a U.S.-based CPA or Enrolled Agent to prepare and file your Delaware business return. Upfront pricing, secure document upload, no surprises.
Connect with a TaxPro →Delaware Business Tax Extension – LLC / Partnership
Form PRT-EXT • LLC / PartnershipDelaware LLC & Partnership Tax Extension
Delaware LLCs and partnerships report income to the Delaware Division of Revenue. Delaware aligns its extension process with the IRS–a federally approved IRS Form 7004 extension automatically carries over to Delaware, giving you until September 15, 2026 to file your return without any additional state filing.
How the Extension Works
Obtain a federal extension by filing IRS Form 7004 before the March 16, 2026 original deadline (March 15 falls on a Sunday in 2026). Delaware accepts the federal extension–no separate Delaware form is required to activate the state extension. To remit any tax due, use Form PRT-EXT or pay electronically through the Delaware online payment portal. File your completed Delaware partnership return by September 15, 2026.
Best Practices
- File IRS Form 7004 before March 16, 2026 to extend your Delaware LLC or partnership return to September 15, 2026.
- Pay any Delaware pass-through entity tax using Form PRT-EXT by March 16, 2026.
- Use the Delaware online payment portal for fast, confirmed electronic payment.
- File your completed Delaware LLC or partnership return by September 15, 2026.
Working with a Tax Professional
LLC / Partnership returns carry unique complexities – a licensed CPA or Enrolled Agent can navigate the details and ensure your Delaware return is filed accurately and on time.
- Get matched with a verified U.S.-based CPA or Enrolled Agent
- Upload your business documents via secure drag-and-drop
- Review your return with transparent, upfront pricing
- Your TaxPro files the Delaware return by September 15, 2026
How to Pay
Delaware requires online payment for tax amounts of $750 or more. Submit electronically via the Delaware Online Tax Extension Payment portal. For amounts under $750, complete Form PRT-EXT and mail with your payment.
Delaware Online Payment Portal
Submit electronically through the Delaware Online Tax Extension Payment system. Required for all payments $750 and above.
Form PRT-EXT by Check
Download Form PRT-EXT and mail with your check or money order. Include your EIN and tax year on the check.
P.O. Box 830
Wilmington, DE 19899-0830
Late Filing & Payment Penalties
| Penalty Type | Amount |
|---|---|
| Failure to File | 5% of outstanding tax liability per month, up to 50% |
| Failure to Pay | 1% of outstanding tax liability per month, not to exceed 25% |
LLC / Partnership Quick Reference
| State Abbreviation | DE |
| Entity Type | LLC / Partnership |
| Extension Status | Automatic with approved IRS Form 7004 |
| Original Filing Deadline | March 16, 2026 |
| Extended Filing Deadline | September 15, 2026 |
| Payment Due | March 16, 2026 (100% of tax owed) |
| Payment Form | Form PRT-EXT |
| Online Payment | Delaware Online Tax Extension Payment |
| State Agency | Delaware Division of Revenue |
| Failure to File Penalty | 5% of outstanding tax liability per month, up to 50% |
| Failure to Pay Penalty | 1% of outstanding tax liability per month, not to exceed 25% |
Delaware Business Tax Extension – S Corporation
Form PRT-EXT • S CorporationDelaware S Corporation Tax Extension
Delaware S corporations file state income tax returns with the Delaware Division of Revenue. Delaware’s extension process is straightforward–a valid IRS Form 7004 federal extension automatically extends the Delaware S corporation filing deadline to September 15, 2026 with no separate state form required.
How the Extension Works
File IRS Form 7004 before March 16, 2026. Delaware automatically recognizes the federal extension and extends your state filing deadline to September 15, 2026. If Delaware S corporation tax is owed, submit payment using Form 1100-P-EXT by March 16, 2026 and mail to: Delaware Division of Revenue, P.O. Box 830, Wilmington, DE 19899-0830, or pay online at the Delaware payment portal.
Best Practices
- File IRS Form 7004 before March 16, 2026 to automatically extend your Delaware S corporation return to September 15, 2026.
- Remit Delaware S corporation tax with Form 1100-P-EXT by the March 16 original deadline.
- Pay electronically through the Delaware Division of Revenue online portal for confirmed, instant processing.
- File the completed Delaware S corporation return by September 15, 2026.
Working with a Tax Professional
S Corporation returns carry unique complexities – a licensed CPA or Enrolled Agent can navigate the details and ensure your Delaware return is filed accurately and on time.
- Get matched with a verified U.S.-based CPA or Enrolled Agent
- Upload your business documents via secure drag-and-drop
- Review your return with transparent, upfront pricing
- Your TaxPro files the Delaware return by September 15, 2026
How to Pay
Delaware requires online payment for tax amounts of $750 or more. Submit electronically via the Delaware Online Tax Extension Payment portal. For amounts under $750, complete Form PRT-EXT and mail with your payment.
Delaware Online Payment Portal
Submit electronically through the Delaware Online Tax Extension Payment system. Required for all payments $750 and above.
Form PRT-EXT by Check
Download Form PRT-EXT and mail with your check or money order. Include your EIN and tax year on the check.
P.O. Box 830
Wilmington, DE 19899-0830
Late Filing & Payment Penalties
| Penalty Type | Amount |
|---|---|
| Failure to File | 5% of outstanding tax liability per month, up to 50% |
| Failure to Pay | 1% of outstanding tax liability per month, not to exceed 25% |
S Corporation Quick Reference
| State Abbreviation | DE |
| Entity Type | S Corporation |
| Extension Status | Automatic with approved IRS Form 7004 |
| Original Filing Deadline | March 16, 2026 |
| Extended Filing Deadline | September 15, 2026 |
| Payment Due | March 16, 2026 (100% of tax owed) |
| Payment Form | Form PRT-EXT |
| Online Payment | Delaware Online Tax Extension Payment |
| State Agency | Delaware Division of Revenue |
| Failure to File Penalty | 5% of outstanding tax liability per month, up to 50% |
| Failure to Pay Penalty | 1% of outstanding tax liability per month, not to exceed 25% |
Delaware Business Tax Extension – C Corporation
Form PRT-EXT • C CorporationDelaware C Corporation Tax Extension
Delaware C corporations are subject to Delaware corporate income tax, overseen by the Delaware Division of Revenue. A federal IRS Form 7004 extension automatically extends the Delaware C corporation return to October 31, 2026–no separate state form is required beyond the approved federal extension.
How the Extension Works
File IRS Form 7004 before April 30, 2026 to receive Delaware’s automatic 6-month C corporation extension. Delaware does not require a separate state extension form. To pay corporate income tax due, use Form 1100-T-EXT and mail to: Delaware Division of Revenue, P.O. Box 830, Wilmington, DE 19899-0830, or pay through the Delaware online payment portal. File your completed Delaware corporate return by October 31, 2026.
Best Practices
- File IRS Form 7004 before April 30, 2026 to activate the Delaware C corporation extension to October 31, 2026.
- Remit Delaware corporate income tax using Form 1100-T-EXT by April 30, 2026.
- Make electronic payments at the Delaware online payment portal to ensure timely, confirmed processing.
- File your completed Delaware C corporation return by October 31, 2026.
Working with a Tax Professional
C Corporation returns carry unique complexities – a licensed CPA or Enrolled Agent can navigate the details and ensure your Delaware return is filed accurately and on time.
- Get matched with a verified U.S.-based CPA or Enrolled Agent
- Upload your business documents via secure drag-and-drop
- Review your return with transparent, upfront pricing
- Your TaxPro files the Delaware return by October 31, 2026
How to Pay
Delaware requires online payment for tax amounts of $750 or more. Submit electronically via the Delaware Online Tax Extension Payment portal. For amounts under $750, complete Form PRT-EXT and mail with your payment.
Delaware Online Payment Portal
Submit electronically through the Delaware Online Tax Extension Payment system. Required for all payments $750 and above.
Form PRT-EXT by Check
Download Form PRT-EXT and mail with your check or money order. Include your EIN and tax year on the check.
P.O. Box 830
Wilmington, DE 19899-0830
Late Filing & Payment Penalties
| Penalty Type | Amount |
|---|---|
| Failure to File | 5% of outstanding tax liability per month, up to 50% |
| Failure to Pay | 1% of outstanding tax liability per month, not to exceed 25% |
C Corporation Quick Reference
| State Abbreviation | DE |
| Entity Type | C Corporation |
| Extension Status | Automatic with approved IRS Form 7004 |
| Original Filing Deadline | April 30, 2026 |
| Extended Filing Deadline | October 31, 2026 |
| Payment Due | April 30, 2026 (100% of tax owed) |
| Payment Form | Form PRT-EXT |
| Online Payment | Delaware Online Tax Extension Payment |
| State Agency | Delaware Division of Revenue |
| Failure to File Penalty | 5% of outstanding tax liability per month, up to 50% |
| Failure to Pay Penalty | 1% of outstanding tax liability per month, not to exceed 25% |
Delaware Business Tax Extension – Fiduciary / Estate / Trust
Form PRT-EXT • Fiduciary / Estate / TrustDelaware Fiduciary Tax Extension
Delaware estates and trusts are subject to state fiduciary income tax, administered by the Delaware Division of Revenue. Delaware’s fiduciary extension is tied to the federal process–an approved IRS Form 8868 automatically extends the Delaware fiduciary return deadline to October 31, 2026.
How the Extension Works
Delaware fiduciaries use IRS Form 8868 to obtain a federal extension–once approved, the Delaware fiduciary return is automatically extended to October 31, 2026. No separate Delaware fiduciary extension form is required. Remit any tax owed using Form FID-EXT by April 30, 2026 and mail payments to: Delaware Division of Revenue, P.O. Box 2044, Wilmington, DE 19899-2044 (note the separate P.O. Box for fiduciary payments).
Best Practices
- File IRS Form 8868 before April 30, 2026 to extend your Delaware fiduciary return to October 31, 2026.
- Remit Delaware fiduciary income tax using Form FID-EXT by April 30–one day later than the typical April 15 business deadline.
- Pay electronically through the Delaware online payment portal for immediate payment confirmation.
- File your completed Delaware fiduciary return (Form 400) by October 31, 2026.
Working with a Tax Professional
Fiduciary / Estate / Trust returns carry unique complexities – a licensed CPA or Enrolled Agent can navigate the details and ensure your Delaware return is filed accurately and on time.
- Get matched with a verified U.S.-based CPA or Enrolled Agent
- Upload your business documents via secure drag-and-drop
- Review your return with transparent, upfront pricing
- Your TaxPro files the Delaware return by October 31, 2026
How to Pay
Delaware requires online payment for tax amounts of $750 or more. Submit electronically via the Delaware Online Tax Extension Payment portal. For amounts under $750, complete Form PRT-EXT and mail with your payment.
Delaware Online Payment Portal
Submit electronically through the Delaware Online Tax Extension Payment system. Required for all payments $750 and above.
Form PRT-EXT by Check
Download Form PRT-EXT and mail with your check or money order. Include your EIN and tax year on the check.
P.O. Box 830
Wilmington, DE 19899-0830
Late Filing & Payment Penalties
| Penalty Type | Amount |
|---|---|
| Failure to File | 5% of outstanding tax liability per month, up to 50% |
| Failure to Pay | 1% of outstanding tax liability per month, not to exceed 25% |
Fiduciary / Estate / Trust Quick Reference
| State Abbreviation | DE |
| Entity Type | Fiduciary / Estate / Trust |
| Extension Status | Automatic with approved IRS Form 7004 |
| Original Filing Deadline | April 30, 2026 |
| Extended Filing Deadline | October 31, 2026 |
| Payment Due | April 30, 2026 (100% of tax owed) |
| Payment Form | Form PRT-EXT |
| Online Payment | Delaware Online Tax Extension Payment |
| State Agency | Delaware Division of Revenue |
| Failure to File Penalty | 5% of outstanding tax liability per month, up to 50% |
| Failure to Pay Penalty | 1% of outstanding tax liability per month, not to exceed 25% |
Extended? Your Delaware Business Return Deadline Is Coming Up.
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