State Tax Calculator

How to use the state income tax calculator

What this calculator does

This calculator estimates personal state income tax from four inputs: State, Tax year, Filing status, and Annual taxable income. It applies a transparent state profile – no broad-based tax, flat rate, or simplified progressive brackets – to show an estimated tax bill, effective rate, marginal rate, after-state-tax income, and a bracket-by-bracket calculation. It is designed for budgeting, relocation comparisons, payroll planning, and rough scenario testing. It does not prepare a tax return or determine legal liability.

When to use it

Use it when comparing the cash impact of living in different states, estimating how a raise may change state tax, checking whether withholding is broadly in range, or building a personal budget before a move. For official filing rules, begin with the IRS directory of state government tax websites and then review the relevant state revenue department.

How to calculate

1. The calculator opens with a complete California demonstration: 2026, single filer, and $85,000 of taxable income. The first estimate and Excel workbook are immediately available.
2. Select the State where the income is taxable. Choose the applicable Tax year and Filing status.
3. Replace Annual taxable income with the amount remaining after deductions under the state's rules. Enter digits with an optional decimal point; commas are accepted only as thousands separators.
4. Read Estimated state income tax, Effective tax rate, Marginal tax rate, After-state-tax income, and the Bracket calculation table.
5. Select Download Excel to export the current validated model. Reset clears the demonstration and calculated content; Excel export stays disabled until a complete valid state is entered again.

Input guide

State is required and accepts one U.S. state. Changing it can switch the model among no broad-based tax, flat-rate, and progressive methods. Tax year is required and accepts 2023 – 2026; the year applies a small indexed adjustment to planning thresholds where relevant. Filing status is required; married filing jointly and head of household scale bracket thresholds because many states use wider bands for those statuses. Annual taxable income is required, must be a finite number from $0 to $1 billion, and should be taxable income rather than salary or gross receipts. A common mistake is entering gross income before deductions, which usually overstates the estimate.

Output guide

Estimated state income tax is the modeled dollar amount. Effective tax rate is tax divided by taxable income; it is normally lower than the marginal rate in a progressive system. Marginal tax rate is the rate applied to the last modeled dollar and is useful for evaluating incremental income. After-state-tax income is taxable income minus estimated state tax, not take-home pay. Tax method identifies the model type. The Bracket calculation table shows each threshold band, the income falling inside it, the rate, and tax produced by that band. Zero tax can mean the selected state has no broad-based individual income tax or that income falls below the model's taxable threshold.

Worked example

For the startup example – California, 2026, single, and $85,000 taxable income – the simplified brackets tax successive portions rather than applying the highest rate to the entire amount. The modeled bracket taxes sum to $3,340.00. Dividing $3,340 by $85,000 gives an effective rate of 3.93%, while the final modeled dollars fall in the 8.00% bracket. After-state-tax income is therefore $81,660.00. These figures match the initial screen and exported workbook.

Learn more

State systems vary widely. The Tax Foundation's state individual income tax rate and bracket overview is useful for comparing structures, while the Federation of Tax Administrators' state tax agency directory helps locate official filing guidance.