Guides
State vs Federal Income Tax: The Key Differences
State vs federal income tax describes two separate systems that tax the same paycheck under different rules. Federal income tax is levied by the U.S. government, collected by the IRS, and uses one progressive rate schedule (10% to 37% in 2026) that applies in every state. State income tax is set by each state, and the rules vary widely: some states use progressive brackets, some charge a single flat rate, and nine states tax no wage income at all. Most filers who owe both file two returns each year and calculate the state return using figures carried over from the federal one.
The two systems at a glance
The federal system is uniform nationwide; the state system is 51 separate regimes (50 states plus the District of Columbia). Federal tax funds national programs like Social Security, Medicare, defense, and interest on the debt. State tax funds state-run services such as public schools, roads, Medicaid match, and public safety. The IRS administers the federal tax; a state department of revenue administers each state tax.
| Feature | Federal income tax | State income tax |
|---|---|---|
| Levied by | U.S. federal government | Individual state (or D.C.) |
| Collected by | IRS | State department of revenue |
| Rate structure | Progressive, 7 brackets (10% to 37%) | Flat, progressive, or none, depending on state |
| Top rate (2026) | 37% | 0% to 13.3% (California) |
| Applies where | All 50 states and D.C. | Only in states that impose it |
| Starting point | Gross income | Often federal AGI or federal taxable income |
| Return filed | Form 1040 | State-specific return |
| Standard deduction | Federal amount, set by IRC | Set by state; some allow no itemizing, some none |
The practical result: two people earning identical wages can owe very different total income tax depending on which state they live in, because the federal portion is the same but the state portion ranges from nothing to double digits.
How the federal income tax works
Federal income tax is a progressive tax with seven brackets in 2026, running from 10% up to 37%. Progressive means each slice of income is taxed at the rate for its bracket, not a single rate on the whole amount, so your marginal rate (the rate on your last dollar) is higher than your effective rate (total tax divided by total income). The same brackets, standard deduction, and credits apply whether you live in Texas or Vermont.
Federal taxable income starts from gross income, subtracts adjustments to reach adjusted gross income (AGI), then subtracts the standard deduction or itemized deductions. The IRS indexes the brackets and the standard deduction for inflation each year. Understanding the split between your marginal and effective tax rate matters more here than at the state level, because the federal spread between brackets is wider. For the current thresholds, see the 2026 federal income tax brackets and rates.
How state income tax works: flat, progressive, or none
State income tax structure falls into three groups. Nine states impose no broad-based tax on wage income. Roughly 14 states apply a single flat rate to all taxable income. The remaining states and D.C. use progressive brackets, similar in shape to the federal system but with their own rates and cutoffs. A state’s choice of structure, not just its top rate, drives who pays more.
No income tax (9 states): Alaska, Florida, Nevada, South Dakota, Texas, Washington, and Wyoming tax no individual income. Tennessee and New Hampshire round out the group after phasing out their taxes on interest and dividend income. These states often raise revenue through higher sales or property taxes instead, so a zero income tax rate does not always mean a lower overall tax burden. Note that Washington levies a separate 7% tax on certain long-term capital gains above a threshold, which functions like a narrow income tax.
Flat rate (about 14 states): States including Arizona (2.5%), Indiana, Pennsylvania, and Georgia (dropping to 4.99% for 2026) apply one rate to every dollar of taxable income. Several states cut their flat rates for 2026, including Kentucky, which lowered its rate to 3.5%.
Progressive brackets (about 27 states and D.C.): These states tax higher income tiers at higher marginal rates. California reaches 13.3% on income above $1 million (including its 1% Mental Health Services surtax), the highest state rate in the country. New York’s state income tax is another progressive example with brackets that climb into the double digits at high incomes.
| State structure | Approx. count | Examples | Rate behavior |
|---|---|---|---|
| No wage income tax | 9 | TX, FL, WA, NV, WY, SD, AK, TN, NH | 0% on wages |
| Flat rate | ~14 | AZ 2.5%, GA 4.99%, KY 3.5% | One rate on all taxable income |
| Progressive | ~27 + D.C. | CA up to 13.3%, NY, MN | Rate rises with income tier |
Because a flat state taxes the first dollar at the full rate while a progressive state may charge 0% to 2% on the first band, a low flat rate can beat a progressive state for high earners but cost low earners more. The comparison depends on income level, not headline rate alone.
Conformity and decoupling: why state rules track (and diverge from) federal rules
Conformity is how a state ties its tax code to the federal Internal Revenue Code, and it is the main reason the two systems interact. Most states start their calculation from a federal figure, usually federal AGI or federal taxable income, so a federal change can flow straight into state tax. States then decouple from specific provisions they choose not to follow, which is why state taxable income rarely matches federal taxable income exactly.
There are two conformity models. Rolling conformity states automatically adopt federal changes as Congress makes them, unless the legislature affirmatively decouples from a provision. Static (fixed date) conformity states adopt the IRC as of a set date and must pass a law to pick up later federal changes. A third group conforms only to selected sections.
The 2025 One Big Beautiful Bill Act (OBBBA) put this in motion. In 2026, states are still deciding which OBBBA provisions to follow. Virginia, for example, updated its conformity date to December 31, 2025 and decoupled from several OBBBA provisions, while Idaho conformed to the IRC as of January 1, 2026 with specific carve-outs. The takeaway: a deduction or exclusion that is allowed federally may or may not be allowed on your state return, depending on your state’s conformity posture that year.
The SALT deduction: where the two systems collide
The state and local tax (SALT) deduction lets itemizers subtract state income tax (or sales tax) plus property tax on their federal return, which is the clearest point where paying state tax lowers your federal tax. OBBBA raised the SALT cap from $10,000 to $40,000 for 2025 and $40,400 for 2026, so a filer in a high-tax state can now deduct far more state and local tax federally than under the prior $10,000 limit.
The higher cap phases down once modified AGI exceeds $505,000 in 2026, reducing the benefit for high earners, and is scheduled to revert to $10,000 in 2030 unless Congress acts. The deduction only helps taxpayers who itemize on Schedule A instead of taking the standard deduction; filers who take the standard deduction get no SALT benefit at all. To decide, compare the two under the standard vs itemized deduction rules.
Business owners in pass-through entities may have a separate route. Many states now offer a pass-through entity tax (PTET) that shifts the state tax to the entity level, where it is deductible without the individual cap. See the pass-through entity tax (PTET) SALT cap workaround for how the election works state by state.
Filing both returns
Most taxpayers in a state with income tax file two returns each season: the federal Form 1040 and a state return. Prepare the federal return first, because the state return typically starts from a federal number (often AGI) and then applies state additions, subtractions, and rates. Filing one does not file the other, and the two can have different deadlines, though many states match the federal mid-April date.
- Complete the federal return. Calculate federal AGI and taxable income on Form 1040. This produces the figures most states use as their starting point.
- Carry the federal figure to the state return. Enter federal AGI or taxable income where the state form requires it.
- Apply state additions and subtractions. Add back items the state does not allow and subtract items it exempts (for example, some states exempt Social Security or municipal bond interest).
- Apply the state rate. Use the flat rate or the state’s brackets to compute state tax, then subtract state credits and withholding.
- File both. Submit to the IRS and to the state department of revenue separately, and pay any balance to each.
People who live in one state and work in another, or who move mid-year, may file in more than one state and claim a credit for taxes paid to another state to avoid double taxation. Rules vary by state and by any reciprocity agreement between them.
FAQ
Do I have to pay both state and federal income tax?
Most workers pay federal income tax regardless of where they live, because it is uniform nationwide. Whether you also pay state income tax depends on your state: nine states tax no wage income, so residents there generally pay only federal income tax. In the other 41 states and D.C., you typically owe both and file two returns.
Why is my state tax lower than my federal tax?
State rates are usually far lower than federal rates. The top federal rate is 37% in 2026, while most state top rates fall between roughly 3% and 13%, and many flat-rate states sit under 5%. State tax also often starts from a smaller base after state-specific subtractions, so the state figure on the same income is commonly a fraction of the federal figure.
Which states have no income tax in 2026?
Nine states impose no broad-based tax on wage income: Alaska, Florida, Nevada, South Dakota, Texas, Washington, and Wyoming, plus Tennessee and New Hampshire after they phased out taxes on interest and dividends. These states often rely more on sales and property taxes, so a 0% income tax rate does not always mean a lower total tax burden.
What is state tax conformity?
Conformity is how a state ties its income tax to the federal Internal Revenue Code. Rolling conformity states adopt federal changes automatically unless they decouple; static conformity states adopt the code as of a fixed date and must legislate to follow later changes. Conformity is why state taxable income usually starts from a federal figure but rarely matches it exactly.
Does paying state income tax reduce my federal tax?
It can, but only if you itemize. The SALT deduction lets itemizers subtract state and local income (or sales) and property taxes on the federal return, capped at $40,400 for 2026 and phasing down above about $505,000 of modified AGI. Filers who take the standard deduction receive no SALT benefit. The cap is scheduled to drop back to $10,000 in 2030.
Do I file one return or two?
If your state has an income tax, you generally file two: a federal Form 1040 and a separate state return. Complete the federal return first, since the state return usually starts from federal AGI or taxable income. Residents of the nine no-income-tax states typically file only the federal return unless they earned income in another taxing state.
Can I be taxed by two states at once?
Yes, if you live in one state and work in another, or move mid-year. To prevent double taxation, states generally let you claim a credit for income tax paid to another state, or apply a reciprocity agreement that lets you owe tax only to your home state. The exact mechanics depend on the states involved.
Reviewed by The Ledgerism Editorial Team. Last reviewed: July 2026.