State income tax

State income taxes are a separate obligation from federal taxes. Most states impose their own income tax on residents and on nonresidents who earn income within the state.

48 steps across 12 sections

1. 1. Determine If You Must File

  • Check your state's revenue department website for filing thresholds
  • Consider all income sources: wages, self-employment, investments, rental income
  • If you lived or worked in multiple states, you may owe multiple returns

2. 2. Gather Documents

  • Federal tax return (many state returns reference federal AGI)
  • W-2s (showing state wages and state tax withheld per state)
  • 1099s (interest, dividends, freelance income)
  • State-specific schedules or forms (varies by state)
  • Records of estimated tax payments made to the state
  • Moving dates if you changed states during the year

3. 3. Choose Filing Method

  • State e-file portal Many states offer free direct e-filing
  • Commercial software TurboTax, H&R Block, TaxSlayer, FreeTaxUSA — most include state filing (some for a fee)
  • Paper filing Download forms from your state's revenue website
  • Tax professional Recommended for multi-state or complex situations

4. 4. Complete the State Return

  • Start with your federal AGI (most states use this as the starting point)
  • Apply state-specific additions and subtractions (some income taxed federally may be exempt at state level, and vice versa)
  • Calculate state taxable income
  • Apply the state's tax rate or bracket schedule
  • Claim applicable state credits (child care, education, property tax, etc.)
  • Subtract taxes already withheld or estimated payments made

5. 5. Handle Multi-State Situations

  • File nonresident returns FIRST for states where you worked but did not live
  • Then file your resident return, claiming credits for taxes paid to other states
  • Check for reciprocity agreements that may simplify things

6. 6. File and Pay

  • E-file or mail by the state deadline (usually April 15, but not always)
  • Pay any balance due; set up payment plans if needed
  • Keep copies of all returns for at least 3-4 years

7. Key Caveats

  • Washington now taxes capital gains (7% on gains exceeding $270,000), so high-earning investors still face a state tax
  • New Hampshire taxes business profits and has among the highest property taxes nationally
  • Alaska and New Hampshire are the only states with neither income tax nor statewide sales tax
  • No-income-tax states typically compensate with higher sales taxes, property taxes, or industry-specific taxes
  • Moving to a no-income-tax state does not eliminate all state tax obligations

8. When You Must File in Multiple States

  • You live in one state and work in another
  • You moved during the tax year (part-year resident in two states)
  • You have rental property or business income in another state
  • You are a remote worker whose employer is in a different state
  • You travel for work and perform services in multiple states

9. How to Avoid Double Taxation

  • File a nonresident return in each state where you earned income but did not live
  • File a resident return in your home state
  • Claim a credit for taxes paid to other states on your resident return
  • Most states allow this credit, preventing the same income from being taxed twice

10. Filing Order Matters

  • Always complete nonresident state returns first
  • Use the tax amounts from nonresident returns to calculate credits on your resident return

11. Reciprocity Agreements (2026)

  • Submit a state tax exemption form to your employer (e.g., VA-4 in Virginia, WH-47 in Indiana)
  • The employer withholds taxes for your home state instead of the work state
  • You do NOT need to file a nonresident return in the work state if the exemption is properly filed

12. Extension Rules

  • Most states grant automatic extensions if you file a federal extension (Form 4868)
  • Some states require a separate state extension form
  • An extension to FILE is NOT an extension to PAY — estimated taxes are still due by the original deadline
  • Penalties and interest accrue on unpaid balances from the original due date

Common Mistakes

  • Not filing the exemption form
  • Assuming reciprocity exists
  • Not verifying withholding
  • New York City
  • Ohio cities

Sources

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