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Tax year 2026

Iowa vs South Dakota Income Tax — 2026

A single filer earning $100,000 pays $3,148 less per year in South Dakota than in Iowa — $262 a month. Iowa charges $3,148; South Dakota charges $0.

Why this pair has a page: bordering states.

Iowa at $100K
$3,148
3.15%
South Dakota at $100K
$0
0.00%
Annual difference
$3,148
$262 a month
National ranks
17 vs 5
of 50, lowest tax first

The bill at every income

Single filer, standard deduction, no dependents. State income tax only.

Iowa and South Dakota income tax compared at seven income levels, 2026
Gross incomeIowa taxSouth Dakota taxDifference
$50,000$1,248$0$1,248 less in SD
$75,000$2,198$0$2,198 less in SD
$100,000$3,148$0$3,148 less in SD
$150,000$5,048$0$5,048 less in SD
$250,000$8,848$0$8,848 less in SD
$500,000$18,348$0$18,348 less in SD
$1,000,000$37,348$0$37,348 less in SD
Annual state income tax, Iowa versus South Dakota
IA at $50,000: $1,248IA at $50,000$1,248SD at $50,000: $0SD at $50,000$0IA at $75,000: $2,198IA at $75,000$2,198SD at $75,000: $0SD at $75,000$0IA at $100,000: $3,148IA at $100,000$3,148SD at $100,000: $0SD at $100,000$0IA at $150,000: $5,048IA at $150,000$5,048SD at $150,000: $0SD at $150,000$0IA at $250,000: $8,848IA at $250,000$8,848SD at $250,000: $0SD at $250,000$0IA at $500,000: $18,348IA at $500,000$18,348SD at $500,000: $0SD at $500,000$0IA at $1,000,000: $37,348IA at $1,000,000$37,348SD at $1,000,000: $0SD at $1,000,000$0

How the two systems differ

Iowa and South Dakota income tax systems compared
IowaSouth Dakota
Tax structureFlat rateNo income tax
Top marginal rate3.8%None
Number of brackets1—
Standard deduction (single)$16,100—
Personal exemption$40 credit—
Local income taxesYesNo
Capital gainsordinarynone
Population (2024)3,241,488924,669

By filing status

Iowa and South Dakota tax on $100,000 by filing status, 2026
Filing statusIowaSouth DakotaDifference
Single$3,148$0$3,148 less in SD
Married filing jointly$2,496$0$2,496 less in SD
Married filing separately$3,148$0$3,148 less in SD
Head of household$2,842$0$2,842 less in SD

Change the assumptions

Adjust income and filing status, or swap either state. The URL updates so you can share the exact comparison.

At $100,000 as a single filer, South Dakota costs $3,148 less per year than Iowa — $262 a month.

Iowa compared with South Dakota at $100,000
IowaSouth DakotaDifference
State income tax$3,148$0$3,148
Per month$262$0$262
Effective rate3.15%0.00%3.15 pts
Marginal rate3.8%None3.80 pts
Standard deduction$16,100—$16,100
Taxable income$83,900—$83,900
Tax structureFlat rateNo income tax
Local income taxesYesNo

Local taxes are not included above. Iowa has localities that levy their own income tax on top of the state figure. See each state page for the rates that apply.

Full detail: Iowa · South Dakota · methodology

Local income taxes change this picture

What this comparison leaves out

Sources for both states

  1. 1.Iowa Department of RevenueState revenue department
    IDR Announces 2026 Individual Income Tax and Interest Rates
    https://revenue.iowa.gov/press-release/2025-10-21/idr-announces-2026-individual-income-tax-and-interest-rates
    Retrieved
  2. 2.Tax FoundationResearch organisation (cross-check)
    State Individual Income Tax Rates and Brackets, 2026
    https://taxfoundation.org/data/all/state/state-income-tax-rates-2026/
    Retrieved
  3. 3.South Dakota Department of RevenueState revenue department
    Individuals - Taxes
    https://dor.sd.gov/individuals/taxes/
    Retrieved

Figures on this page were last checked against these sources on . Found something wrong? Report it.