Flat vs Progressive State Income Tax: Which States Use Which, and Who Pays More

The federal income tax is progressive — rates climb in steps as income rises. State income taxes are split. Roughly a dozen states apply a single flat rate to everyone, most of the rest use brackets, and nine tax wage income not at all. Which camp your state falls into changes how your tax bill responds to a raise, and it changes who in your state carries the load.

The Two Structures

Progressive systems slice your taxable income into bands and tax each band at its own rate. California runs nine brackets from 1% to 12.3%. Hawaii runs twelve, from 1.4% to 11%. New York runs nine, topping out at 10.9%. The rate on your last dollar — your marginal rate — is always higher than the rate on your income as a whole.

Flat systems apply one rate to all taxable income. Pennsylvania charges 3.07%, Illinois 4.95%, Michigan 4.25%, North Carolina 4.5%, Arizona 2.5%, Colorado 4.4%, Utah 4.55%, Georgia 5.39%, Idaho 5.695%, Kentucky 4%, Indiana 3.05%, Massachusetts 5%, and Mississippi effectively runs a two-step schedule that behaves like a flat tax above its exempt band.

The direction of travel over the past few years has been decisively toward flat. Arizona, Georgia, Idaho, Iowa, Mississippi, and Louisiana have all either adopted a flat rate or legislated a phased path to one. Louisiana moved to a flat 3% starting in the 2025 tax year, replacing the three-bracket structure it used through 2024.

Why Your Marginal Rate Isn't Your Real Rate

This is the single most misunderstood point in personal tax, and it matters more in progressive states.

If you live in California and earn enough to reach the 9.3% bracket, you do not pay 9.3% on your income. You pay 1% on the first slice, 2% on the next, 4% on the next, and so on, and 9.3% only on the portion inside that band. Your effective rate — total tax divided by total income — lands far below 9.3%.

The practical consequence: a raise never reduces your take-home pay. Crossing into a higher bracket taxes only the dollars above the threshold at the higher rate. Every dollar below stays taxed exactly as it was. People turn down bonuses and overtime over this misconception every year, and it costs them real money.

In a flat state the question doesn't arise. Marginal and effective rates converge, differing only because of the standard deduction.

The Deduction Is Doing More Work Than the Rate

Comparing headline rates between states is close to useless without also comparing what gets subtracted first.

Pennsylvania's 3.07% looks like one of the friendliest rates in the country. It applies to essentially your full income — Pennsylvania grants no standard deduction and no personal exemption. Someone earning $45,000 there pays around $1,380.

Arizona's 2.5% is lower still, but Arizona also matches the federal standard deduction at $14,600 for a single filer. That same $45,000 earner has taxable income of $30,400 and pays about $760 — barely half the Pennsylvania bill, despite the rates being within half a point of each other.

The pattern repeats across the country. Illinois calls its $2,775 figure a personal exemption rather than a standard deduction. Indiana's is $1,000. Massachusetts and Michigan use exemptions in the $4,400–$5,600 range. Meanwhile Colorado, Idaho, Utah, and Arizona all track the federal standard deduction, which shelters the first $14,600 of a single filer's income entirely.

Rate times income is not your tax bill. Rate times (income minus deduction) is.

Who Each System Favours

The distributional effect is straightforward arithmetic.

A flat tax charges the same percentage to a $30,000 earner and a $300,000 earner. Because that $30,000 household spends nearly everything it earns while the $300,000 household does not, the same percentage represents a much heavier burden at the bottom. A large standard deduction softens this considerably; a small one does not soften it at all.

A progressive system deliberately shifts the load upward. California's bottom bracket of 1% means a low earner pays almost nothing to the state, while the top bracket of 12.3% — plus a 1% mental health surtax above $1 million, making an effective 13.3% top rate — is among the highest in the nation.

Neither structure is inherently correct; they encode different judgments about who should pay. What matters for your own planning is where you sit in the distribution. If you earn well above your state's median income, a flat state almost certainly costs you less. If you earn below it, a progressive state with a generous bottom bracket usually costs you less.

The Wrinkles That Trip People Up

Some states don't widen brackets for married couples. Alabama, Delaware, DC, Missouri, Ohio, Rhode Island, South Carolina, Virginia, and West Virginia apply identical bracket thresholds regardless of filing status. Two spouses each earning $60,000 pay noticeably more filing jointly there than two single people with the same incomes — a genuine marriage penalty. Most other states double the thresholds for joint filers, which removes it.

Local income taxes are invisible in state comparisons. Every one of Indiana's 92 counties levies its own income tax, roughly 0.5% to 3%. Maryland counties add 2.25% to 3.2%. New York City and Yonkers levy separate city taxes. Ohio has hundreds of municipal income taxes. A state-level comparison that ignores these can be off by several percentage points for someone in the wrong municipality.

Surtaxes sit outside the bracket table. Massachusetts adds a 4% surtax on income above roughly $1,053,750, turning its "flat 5%" into 9% at the top. California's mental health surtax works the same way. These rarely show up in published bracket tables.

Standard deductions phase out. Maine phases its deduction out above about $97,150 of income. Alabama's phases down at higher incomes. Wisconsin's slides on a scale. In each case the effective rate at higher incomes is above what the bracket table alone suggests.

Run Your Own Numbers

Structure arguments are interesting; your actual bill is what matters. Every state has its own income tax calculator here, prefilled with that state's real brackets or flat rate and its real standard deduction, and each one shows your state tax, federal tax, FICA, and resulting take-home pay together. Put the same salary through two states and compare the take-home line — it settles the question faster than any comparison table.