Iowa State Income Tax Calculator
This professional-grade calculator estimates Iowa state income tax for individuals. It’s designed for residents, newcomers, and planners who want a transparent, mobile-first experience. Enter a few values to see your state tax, optional local surtax, effective and marginal rates, and an after-tax breakdown.
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Note: Iowa tax is computed on taxable income. This tool estimates taxable income from gross using the federal standard deduction by default, or you can enter your federal taxable income directly.
Data Source and Methodology
Authoritative source: Iowa Department of Revenue — Individual Income Tax Guidance (Iowa Tax), Tax Year 2024. Direct link: IDR: Iowa Tax (1040 Expanded Instructions).
Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.
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- Rate schedule and structure reflect IDR’s 2024 guidance.
- Calculator estimates Iowa taxable income from gross using federal standard deduction amounts for 2024, unless you choose to enter federal taxable income directly (to align with Iowa’s use of federal taxable base under recent reforms).
The Formula Explained
Taxable income (estimate mode):
I_{IA}^{tax} = \max\left(0,\; G - D_{pre} - SD_{fed}(status, year) \right)
Progressive tax across brackets k = 1..n:
T_{state} = \sum_{k=1}^{n} r_k \cdot \max\!\left(0,\; \min(I_{IA}^{tax}, u_k) - u_{k-1} \right)
where u_k are bracket upper bounds with u_0 = 0.
Local school district surtax:
T_{local} = s \cdot T_{state} \quad \text{with } s = \frac{\text{surtax %}}{100}
Total Iowa tax and after-tax income:
T_{total} = T_{state} + T_{local}
I_{after} = G - D_{pre} - T_{total}
Glossary of Variables
- Gross Income (G): Total annual income before taxes and deductions.
- Pre-tax Deductions (Dpre): Payroll deductions excluded from taxable wages (e.g., traditional 401(k), HSA).
- Federal Standard Deduction (SDfed): The federal deduction by filing status and year (used here to approximate Iowa’s taxable base when you do not enter taxable income directly).
- Iowa Taxable Income (I_IA^tax): The income amount that Iowa taxes after deductions.
- State Tax (Tstate): Sum of tax across Iowa brackets applied to Iowa taxable income.
- Local Surtax (Tlocal): A school district surtax applied as a percentage of the state tax owed.
- Total Iowa Tax (Ttotal): State tax plus local surtax.
- After-Tax Income (Iafter): Take-home income after pre-tax deductions and Iowa tax.
- Effective Rate: Ttotal divided by Gross (or by Iowa taxable income).
- Marginal Rate: The top Iowa bracket rate applicable to your last dollar of taxable income (state portion only).
Come Funziona: Un Esempio Passo-Passo
Scenario: Tax Year 2024, Single, Gross = $75,000, Pre-tax = $5,000, Local Surtax = 5%.
- Taxable Income: 75,000 − 5,000 − 14,600 (federal SD for Single in 2024) = $55,400.
- Apply Iowa brackets (2024):
Bracket 1: 0 – 7,000 @ 4.40% => 7,000 × 0.0440 = $308.00
Bracket 2: 7,000 – 30,000 @ 4.82% => 23,000 × 0.0482 = $1,108.60
Bracket 3: 30,000+ @ 5.70% => 25,400 × 0.0570 = $1,447.80
State tax = $2,864.40
Local surtax (5%) = $143.22
Total Iowa tax = $3,007.62
After-tax income = 75,000 − 5,000 − 3,007.62 = $66,992.38
Frequently Asked Questions (FAQ)
1) Which incomes are included for Iowa tax here?
We tax Iowa taxable income based on your federal taxable base (or direct entry). This aligns with Iowa’s simplified system post-reform. Optional local school district surtax is applied to the state tax owed.
2) Does Iowa tax Social Security benefits?
Social Security benefits are not taxed by Iowa under current rules. Always verify with the Iowa Department of Revenue for your specific case.
3) What about retirement income?
Iowa excludes most retirement income from state taxation under recent reforms. Confirm eligibility and definitions with the IDR.
4) How accurate is estimating from gross income?
It’s a strong estimate when your income is primarily wages and standard deduction applies. For precision, switch to “Enter taxable income” mode and input the federal taxable income from your 1040.
5) Where can I find my local surtax rate?
Check your school district’s published surtax rate or your prior-year Iowa return. If you don’t have one, leave it at 0%.
6) Are brackets different by filing status?
Under 2024 guidance, Iowa uses a simplified bracket structure that generally applies uniformly. This tool implements that schedule.
7) Is this legal or tax advice?
No. This is an educational tool. For personal advice, consult a licensed tax professional and the Iowa Department of Revenue.