State Income Tax Estimator (Detailed) Formula
Understand the math behind the state income tax estimator (detailed). Each variable explained with a worked example.
Formulas Used
Estimated State Tax
state_tax = state_taxable * state_rate / 100Estimated Federal Tax
federal_tax = gross_income * federal_rate / 100Combined Tax Burden
combined_tax = state_taxable * state_rate / 100 + gross_income * federal_rate / 100Combined Effective Rate
combined_rate = gross_income > 0 ? (state_taxable * state_rate / 100 + gross_income * federal_rate / 100) / gross_income * 100 : 0After-Tax Income
take_home = gross_income - state_taxable * state_rate / 100 - gross_income * federal_rate / 100Variables
| Variable | Description | Default |
|---|---|---|
gross_income | Gross Annual Income(USD) | 80000 |
state_rate | State Tax Rate(%) | 5 |
state_deduction | State Standard Deduction(USD) | 5000 |
federal_rate | Approx Federal Effective Rate(%) | 15 |
state_taxable | Derived value= max(gross_income - state_deduction, 0) | calculated |
How It Works
State Income Tax Overview
State income tax rates vary dramatically across the US.
No Income Tax States
Alaska, Florida, Nevada, South Dakota, Texas, Washington, Wyoming (New Hampshire and Tennessee tax only investment income)
Flat Tax States
Colorado (4.4%), Illinois (4.95%), Indiana (3.05%), Michigan (4.25%), North Carolina (4.5%), Pennsylvania (3.07%), Utah (4.65%)
Highest Tax States
California (up to 13.3%), Hawaii (up to 11%), New Jersey (up to 10.75%), New York (up to 10.9%)
Combined Burden
Total Tax = Federal Tax + State Tax
State taxes may be deductible on federal return (SALT deduction, capped at $10,000).
Worked Example
$80,000 income, 5% state rate, $5,000 state deduction, 15% federal effective rate.
- 01State taxable = $80,000 - $5,000 = $75,000
- 02State tax = $75,000 x 5% = $3,750
- 03Federal tax = $80,000 x 15% = $12,000
- 04Combined = $3,750 + $12,000 = $15,750
- 05Combined rate = $15,750 / $80,000 = 19.7%
- 06Take-home = $80,000 - $15,750 = $64,250
Frequently Asked Questions
Is moving to a no-tax state always better?
Not necessarily. No-income-tax states often offset with higher property taxes, sales taxes, or cost of living. Texas has high property taxes. Washington has high sales tax. Look at total tax burden, not just income tax.
Can I deduct state taxes on my federal return?
Yes, through the State and Local Tax (SALT) deduction, but it is capped at $10,000 total ($5,000 married filing separately). This cap means high-income earners in high-tax states cannot deduct the full amount.
What about local income taxes?
Some cities and counties levy their own income taxes. New York City adds up to 3.876%. Many Ohio cities have 2-3% local income taxes. These are in addition to state and federal taxes.
Ready to run the numbers?
Open State Income Tax Estimator (Detailed)