State income tax is money your employer withholds from your paycheck and sends to your state government, based on how much you earn

Not every state has an income tax. Nine states — Alaska, Florida, Nevada, South Dakota, Tennessee, Texas, Washington, Wyoming, and New Hampshire (which taxes only investment income) — do not collect income tax from wages. The other 41 states and Washington, D.C. do. If you live and work in a state with income tax, your employer deducts a percentage of each paycheck and forwards it to that state's revenue department. The amount withheld depends on your income level, how many dependents you claim, and the tax rate your state sets.

State income tax is separate from federal income tax. Both come out of your paycheck, but they go to different governments and fund different things. Federal tax funds national programs like Social Security and Medicare. State tax funds schools, roads, police, and other state services. You file a state tax return once a year in the same way you file a federal return — usually by April 15 — to reconcile what was withheld against what you actually owe.

Key Takeaways

  • State income tax rates range from about 1% to over 13% depending on your state and income level, and nine states do not collect it at all.
  • Your employer withholds state income tax from each paycheck based on a form you fill out (usually a W-4 or state equivalent) that tells them how much to take.
  • You can adjust your withholding if too much or too little is being taken out, which changes how much you owe or get back when you file your return.
  • State income tax is progressive in most states, meaning higher earners pay a higher percentage, though a few states use a flat rate for everyone.

How withholding works and what determines the amount

When you start a job, you complete a withholding form — usually called a W-4 in most states, though some states have their own version. On this form, you tell your employer basic facts: your filing status (single, married, head of household), the number of dependents you claim, and whether you have other income. Your employer uses this information and your state's tax tables to calculate how much to withhold from each paycheck.

The withholding is not the same as your final tax bill. It is an estimate. If you claim zero dependents, your employer withholds more. If you claim several dependents, your employer withholds less. The goal is to withhold roughly what you will owe by the end of the year, so you do not owe a large amount or get a large refund when you file. In practice, most people either owe a small amount or get a refund of a few hundred dollars.

You can change your withholding at any time by submitting a new form to your employer's payroll department. If you are having too much withheld and want more money in each paycheck, you can claim additional dependents or allowances. If too little is being withheld and you owe money at tax time, you can reduce your claims. This is different from changing your actual tax situation — it only changes how much is taken out during the year.

State tax rates and how they vary by income

State income tax rates vary widely. Some states charge a flat rate — everyone pays the same percentage regardless of income. Colorado, Illinois, Indiana, Kentucky, Massachusetts, Michigan, Mississippi, Missouri, North Carolina, and Pennsylvania all use flat rates, which range from about 3% to 5.75%. Most other states use a progressive system, where the rate increases as your income increases. In progressive states, you might pay 3% on your first $30,000 of income, 5% on income between $30,000 and $75,000, and 7% on anything above that.

The highest state income tax rates are in California (up to 13.3%), Hawaii (up to 11%), and New York (up to 10.9%). The lowest rates in states that have income tax are around 1% to 2%. Your actual tax bill also depends on deductions and credits your state allows. Most states let you deduct the federal income tax you paid, mortgage interest, or charitable donations. Some states offer credits for child care, education, or low-income households that reduce your tax bill directly.

Filing your state tax return

You file a state income tax return once per year, usually by April 15, the same deadline as your federal return. You can request an extension to October 15 if you need more time. Your state return asks for the same basic information as your federal return: income from all sources, deductions, dependents, and credits you claim. Many states use the federal return as a starting point — you report your federal taxable income and then make adjustments for state-specific deductions or credits.

You can file by paper or electronically. Most states offer free filing software for households below a certain income threshold (usually around $73,000). If you use a paid tax preparer or software, the cost is the same whether you file state and federal together or separately. When you file, the state compares what you paid in withholding throughout the year to what you actually owe. If you overpaid, you get a refund. If you underpaid, you owe the difference.

Some states allow you to split your refund between your bank account and a savings account, or to apply part of it to next year's taxes. If you owe money, you can usually pay online, by mail, or through an installment plan. Most states charge interest and penalties if you do not pay by the deadline, so it is worth filing on time even if you cannot pay the full amount immediately.

What happens if you move to a different state

If you move during the year, you may owe income tax to two states. Most states tax you based on where you lived and worked during the tax year. If you moved from California to Texas in July, you would owe California income tax for January through June and nothing to Texas (since it has no income tax). You would file a part-year return in California and a non-resident return in Texas, if required.

Some states have reciprocal agreements that prevent you from being taxed twice on the same income. If you live in one state and work in another, you might pay tax only to your state of residence. A few states also offer credits for taxes paid to other states. When you move, contact both your old state's revenue department and your new state to understand your filing obligations. Your employer's payroll department can also help you update your withholding for your new state.

Self-employment and state income tax

If you are self-employed, you still owe state income tax on your business income, but no one withholds it automatically. You are responsible for paying estimated taxes quarterly — on April 15, June 15, September 15, and January 15 of the following year. You calculate your estimated tax based on your expected annual income and send it directly to your state revenue department. If you do not pay enough in estimated taxes, you may owe penalties and interest when you file your annual return.

Self-employed people can deduct business expenses from their income before calculating state tax, just as they do for federal tax. Common deductions include home office expenses, supplies, equipment, and vehicle mileage. Keeping good records of income and expenses throughout the year makes it easier to file your return and reduces the chance of errors. Some states also require self-employed people to register for a business license or seller's permit, depending on the type of work.

Frequently Asked Questions

Do I have to file a state tax return if I did not earn much money?

It depends on your state and your income. Most states have a minimum income threshold — if you earned less than that amount, you do not have to file. The threshold varies by state and filing status, typically ranging from $3,000 to $15,000. Even if you are not required to file, you should if you had taxes withheld, because you may get a refund.

What if I worked in multiple states during the year?

You file a part-year or non-resident return in each state where you worked. Each state taxes only the income you earned there. You report your total income on each return but only claim deductions related to that state's income. Some states offer credits for taxes paid to other states to prevent double taxation, though the rules vary.

Can I claim dependents on my state return if I claim them on my federal return?

Usually yes, but some states have different rules. Most states follow federal rules for dependents, but a few have additional requirements or limits. Check your state's tax instructions or contact your state revenue department to confirm. If you claim a dependent on your federal return but not your state return, your state withholding will be higher.

What if I disagree with my state tax bill?

You can file an appeal or protest with your state revenue department. Most states have a formal process that starts with a written request for reconsideration. You will need to provide documentation supporting your position. If you still disagree after the state reviews your case, you can appeal to your state's tax court. Many states also offer free tax clinics or ombudsman services to help resolve disputes.

Do I owe state income tax on unemployment benefits?

Most states tax unemployment benefits as income. Some states allow you to exclude a portion of benefits, and a few do not tax them at all. When you receive unemployment, you can choose to have taxes withheld, or you can pay estimated taxes quarterly. Check your state's rules when you file your return to see how unemployment is treated.