Business Tax Deadlines

State filing information

Delaware

Business tax filing in Delaware: state returns, sales tax, other business taxes, and the federal dates that apply everywhere.

checked 2026-09-01Verified against Delaware Division of Revenue (Department of Finance); franchise tax and annual reports are handled by the Delaware Division of Corporations (Department of State). 14 sources.

Corporate income tax return

April 15
Corporate income tax return (Form 1100, now labeled CIT-TAX) due on or before the 15th day of the 4th month following the close of the taxable year...

Partnership / S corporation returns

March 15
Partnerships March 15; Same for S corporations

Sales tax return

None
no state or local sales tax; Delaware instead im

Other business taxes

3 taxes
Delaware Gross Receipts Tax; Delaware Corporate Franchise Tax and Annual Report (Division of Corporations)

Delaware Division of Revenue · also franchise tax and annual reports are handled by the Delaware Division of Corporations (Department of State)

Other business taxes

TaxWho owes itDue
Delaware Gross Receipts TaxBusinesses selling goods or providing services in Delaware; tax on total gross revenues with no deductions...Monthly filers: on or before the 20th day of the month for the preceding month
Delaware Corporate Franchise Tax and Annual Report (Division of Corporations)All corporations incorporated in Delaware (exempt domestic corporations file the report but pay no tax)March 1 annually, filed online with the annual report
LLC / LP / General Partnership annual tax (Division of Corporations)Every Delaware LLC, LP and GP; flat $300 per year (no annual report required)June 1 annually; $200 penalty plus interest if late

Rules in full

Corporate income tax

Corporate income tax return (Form 1100, now labeled CIT-TAX) due on or before the 15th day of the 4th month following the close of the taxable year (8.7% rate).

Extension. Automatic six-month extension requested with Form 1100-T-EXT / CIT-EXT (with payment) by the original due date; extended date is the 15th day of the...

Partnerships and S corporations

S corporations are not taxed at entity level but must remit tax on behalf of non-resident shareholders (6.6% on Form 1100S). No PTE election was identified.

Annual report

Due March 1 (corporations; filed together with the franchise tax payment) (Delaware Division of Corporations, Department of State)

Notes

Delaware has renamed its business forms (1100 = CIT-TAX, 1100S = SCT-RTN, 300 = PRT-RTN) and mandates online filing of gross receipts tax since 2021.

What we could not confirm. No Delaware official page stating 'Delaware has no sales tax' was located (secondary sources only; the gross receipts FAQ does not say it). Gross receipts monthly-vs-quarterly dollar thresholds for the look-back test were not published on the fetched pages. Corporate/S-corp/partnership instruction PDFs read were tax-year 2022 versions; the 2026 corporate due-date table confirms the same rules currently.

Federal dates that apply in Delaware

  1. SEP15Tue
    Individuals & Sole Proprietors
    Q3 2026 estimated tax payment (Form 1040-ES)
  2. SEP15Tue
    Partnerships
    Form 1065 extended return (Form 7004), tax year 2025
  3. SEP15Tue
    S-Corporations
    Form 1120-S extended return (Form 7004), tax year 2025
  4. SEP15Tue
    C-Corporations
    Q3 2026 corporate estimated tax (Form 1120-W)
  5. OCT15Thu
    Individuals & Sole Proprietors
    Form 1040 extended return (Form 4868), tax year 2025
  6. OCT15Thu
    C-Corporations
    Form 1120 extended return (Form 7004), tax year 2025

All 2026 federal deadlines

Sources

  1. https://revenue.delaware.gov/ official
  2. https://revenue.delaware.gov/business-tax-forms/ official
  3. https://corp.delaware.gov/frtax/ official
  4. https://revenuefiles.delaware.gov/2022/1100_TY22Instructions.pdf official
  5. https://revenuefiles.delaware.gov/2025/2026_Corp_Due_Dates_Table.pdf official
  6. https://revenuefiles.delaware.gov/2022/1100S_TY22Instructions.pdf official
  7. https://revenuefiles.delaware.gov/2022/300_TY22Instructions.pdf official
  8. https://corp.delaware.gov/paytaxes/ official
  9. https://revenue.delaware.gov/frequently-asked-questions/gross-receipts-tax-faqs/ official
  10. https://revenuefiles.delaware.gov/docs/2026_GR_DueDateTable.pdf official
  11. https://www.expressextension.com/statetaxextension/delaware/business-tax-extension/
  12. https://www.instead.com/state-tax-deadlines/2025-delaware-state-tax-deadlines
  13. https://www.salestaxinstitute.com/jurisdiction/delaware
  14. https://www.taxjar.com/sales-tax/delaware

Checked 2026-09-01; researcher confidence 0.85. Corrections with a link to the state's own page: contact@businesstaxdeadlines.com.