Delaware State Tax Filing Guide: Forms & Deadlines

1. What Is Delaware State Tax Filing?

Delaware State Tax Filing is the annual requirement to report income earned during the tax year to the My Delaware Taxes. This filing applies to residents, part-year residents, and nonresidents who have Delaware-source income.

Delaware state income tax is separate from federal income tax and must be filed even if you have already submitted your federal return to the Internal Revenue Service.

2. Who Must File Delaware State Income Tax?

You must file a Delaware state income tax return if you are a resident, part-year resident, or nonresident who earned income from Delaware sources during the tax year. Filing requirements are based on residency status, income level, and the type of income earned.

Quick checklist (common scenarios)

1. Delaware residents: required to file if income exceeds Delaware filing thresholds
2. Part-year residents: must report income earned while living or working in Delaware
3. Nonresidents: must file if they earned income sourced from Delaware
4. Self-employed individuals: must report Delaware business or freelance income
5. LLC members and sole proprietors: must file Delaware returns for pass-through income

3. Your Filing Status and Income Type Decide Delaware Tax Forms

Delaware State Tax Filing does not use a single form for all taxpayers. The form you must file depends on your residency status and the type of income earned during the tax year. Delaware uses different forms for residents, nonresidents, and taxpayers with simple income.

Key idea

1. Delaware resident: commonly files Form 40 or Form 40A based on income complexity
2. Part-year resident: files Form 40NR to report Delaware-source income
3. Nonresident: files Form 40NR for income earned from Delaware sources
4. Self-employed taxpayer: reports business income on the appropriate Delaware form
5. Federal return reference: Delaware filing uses federal income figures as a base

Confirming your residency status and income source early helps ensure accurate Delaware state income tax filing and reduces the risk of notices from the Delaware Division of Revenue.

4. Documents Required for Delaware State Tax Filing

Preparing accurate documents in advance helps ensure smooth Delaware State Tax Filing and reduces the risk of delays, notices, or penalties from the Delaware Department of Revenue.

1. W-2 and 1099 forms: reporting wages, contractor income, or other earnings
2. Federal tax return: Form 1040 used as a reference for Delaware filing
3. Delaware withholding records: state tax withheld from income, if applicable
4. Business income records: profit and expense details for self-employed taxpayers
5. Prior year Delaware return: helpful for consistency and carryforward items

5. DIY vs Accountant vs Managed Filing

Taxpayers and business owners usually choose one of three approaches: do it themselves, hire an accountant, or use a managed process. The right choice depends on complexity, time, and risk tolerance.

What typically changes your complexity?

1. Multiple LLCs or multiple partners
2. US-source income / withholding / treaty-related details
3. High bank activity and many transactions

Why founders choose managed filing

1. Fewer missed items and fewer back-and-forth messages
2. Clear checklist + timeline
3. More confidence that forms match the entity type

6. Step-by-Step: How to File Delaware State Income Tax

Step 1: Confirm your Delaware residency status

Start by determining whether you are a Delaware resident, part-year resident, or nonresident. Residency status determines whether you file Form 40, Form 40A, or Form 40NR for Delaware State Tax Filing.

Step 2: Gather income records and federal return details

Collect W-2s, 1099s, and your federal income tax return. Delaware state income tax filing uses federal income figures as the starting point for calculating state tax.

Step 3: Review Delaware-specific deductions and withholding

Verify Delaware tax withheld and applicable deductions, including the Delaware deduction for federal income tax paid. Accurate withholding information helps prevent balances due or delayed refunds.

Common filing deadline: April 15 for most calendar-year filers

Step 4: Prepare and review the Delaware tax return

Complete the appropriate Delaware tax form using the My Delaware Taxes (Delaware’s official tax portal) portal, approved tax software, or professional assistance. Review entries carefully before submission.

Step 5: Submit the return and retain confirmation

File your return electronically or by mail and keep a copy of the filed return, payment confirmation, or refund notice for your records.

Step 6: Plan for next tax year

Maintain organized income and expense records throughout the year to simplify future Delaware State Tax Filing and reduce the risk of errors.

Helpful IRS reference:

• IRS Small Business and Self-Employed resources
• Employer Identification Number information

If you prefer guided assistance, FormLLC can help confirm your Delaware filing requirements and coordinate the preparation process.

7. Tips to Avoid Delaware Tax Notices and Penalties

• File your Delaware state income tax return by the April 15 deadline
• Pay any tax due even if you request an extension to file
• Verify Delaware tax withholding amounts before submission
• Keep copies of filed returns and payment confirmations
• Respond promptly to any notices from the Delaware Division of Revenue

8. Delaware Tax Costs, Penalties, and Filing Timelines

• Filing preparation cost: Varies based on income type and filing method used
• Record cleanup: Optional but helpful if income or withholding records are incomplete
• Late filing penalty: Greater of 10 percent of tax due or $50
• Interest on unpaid tax: Accrues at rates set annually by the Delaware Department of Revenue
• Filing extensions: Automatic until October 15; no form or request required

9. Common Federal and Delaware Tax Forms

1. EIN (Employer Identification Number)

An Employer Identification Number (EIN) is issued by the Internal Revenue Service and is used to identify a business for federal and state tax reporting, including Delaware state income tax filing for businesses and self-employed individuals.

2. Federal Partnership Return (Form 1065)

Multi-member LLCs file a federal informational return using Form 1065 . Income reported on Schedule K-1 is used to complete Delaware state income tax returns for individual partners.

3. Federal Corporate Return (Form 1120)

US C-Corporations file Form 1120 at the federal level. Corporate income figures are used to determine Delaware tax obligations when applicable.

4. Delaware Individual Income Tax Forms

• Form 40: Delaware resident individual income tax return.
• Form 40A: Short form for Delaware residents with simple tax situations.
• Form 40NR: Required for nonresidents and part-year residents with Delaware-source income.

5. Owner Individual Filing (when applicable)

• Individuals report Delaware income using Form 40, 40A, or 40NR based on residency
• Partners use Schedule K-1 information to complete Delaware individual returns
• Federal ITIN or SSN may be required for individual Delaware tax filing

10. Conclusion

Delaware State Tax Filing is a yearly responsibility for individuals and businesses with income connected to Delaware. Filing accurately and on time helps avoid penalties, interest, and unnecessary correspondence from the Delaware Division of Revenue.

By understanding Delaware filing requirements, deadlines, and forms, taxpayers can complete their state returns with confidence. FormLLC provides clear guidance to help streamline the Delaware State Tax Filing process.