Nine brackets, a flat rate — or nothing at all
State income tax is where two identical job offers diverge. Texas, Florida and Washington levy no tax on wages at all; Illinois, Pennsylvania, Georgia and Colorado apply a single flat rate; California, New York and New Jersey run multi-bracket schedules that top out above 9%. NetWage parameterizes the ten states in the calculator selector — the same $75,000, single-filer salary computed through each:
| State | State income tax | Other payroll tax | Annual take-home |
|---|---|---|---|
| TX | — | — | $61,592.50 |
| FL | — | — | $61,592.50 |
| WA | — | $435.00 | $61,157.50 |
| CA | $2,927.57 | $975.00 | $57,689.93 |
| NY | $3,520.00 | — | $58,072.50 |
| IL | $3,571.43 | — | $58,021.07 |
| PA | $2,302.50 | — | $59,290.00 |
| NJ | $2,651.25 | — | $58,941.25 |
| GA | $3,269.70 | — | $58,322.80 |
| CO | $2,591.60 | — | $59,000.90 |
The spread between Texas and California is $3,902.57 a year — almost $325 a month — on the same gross, the same filing status, the same federal tax. Note that the gap is not only income tax: California's line includes SDI (1.30%, uncapped) and Washington's zero-income-tax stub still carries the WA Cares long-term-care premium (0.58%).
Reading your own state's structure
Three structural questions explain most of the spread. Does the state tax wages at all? TX, FL and WA answer no (WA does tax large capital gains, but that is not wage income). Flat or progressive? Illinois takes 4.95% of nearly every dollar after a small exemption; Colorado applies 4.40% to federal taxable income, so your federal deductions carry over. Pennsylvania's 3.07% hits gross with no standard deduction at all — the rare state where the rate understates itself least at low income.
What payroll taxes does the state add? Beyond income tax, some states withhold their own premiums: CA SDI, WA Cares, paid family leave programs. They are small percentages but they apply to every wage dollar.
Flat states are not all alike either
« Flat tax » hides real design differences. Illinois applies its 4.95% after a personal exemption; Pennsylvania taxes gross with no deduction whatsoever, which makes its low 3.07% comparatively heavier at modest incomes; Colorado simply takes 4.40% of federal taxable income, so anything that lowers your federal base — standard deduction, 401(k) — lowers the Colorado bill automatically. And bracket states vary wildly in where the top rate starts: California's 9.3% kicks in under $75,000 while New York's top rates only matter well above $200,000.
Which state taxes you — it is not always obvious
In principle your resident state taxes your worldwide income, and states where you work can also tax wages earned there — nonresidents file a return in each work state and claim a credit at home. Remote work blurs this further: some states tax you wherever your laptop sits, a few (notably New York's « convenience of the employer » rule) tax you where the office is even if you never visit. Border states often sign reciprocal agreements so commuters pay only at home. The engine models your state of residence — the common case — not multi-state situations.
Two caveats before you relocate
First, income tax is one line of a broader cost picture — states fund themselves through property, sales and excise taxes instead. Second, city taxes exist on top (New York City, Detroit, several Ohio and Pennsylvania municipalities) and are outside this engine's scope; so are state-specific credits. Every state table used here is cited with its official source — FTB for California, the NY Tax Department, state DOR pages — on the methodology page. Run your own comparison in the salary calculator. Indicative estimate computed with the official parameters in force — not a pay slip, and not tax or legal advice.