Iowa Income Tax Calculator 2026 โ Flat 3.9%
Calculate your 2026 Iowa state income tax at the new flat 3.9% rate. Standard deduction $2,210/$5,450, $40 dependent credit. Old graduated vs new flat savings comparison.
Iowa Tax Calculation Breakdown (2026)
Iowa Income Tax 2026 โ Flat 3.9% Reform
Iowa's 2026 flat tax of 3.9% represents the culmination of multi-year tax reform. Iowa uses its own (much lower) standard deduction rather than mirroring federal amounts, and federal tax deductibility was eliminated alongside the flat rate transition.
Calculation Formula
IA Tax (before credit) = IA Taxable Income ร 3.9%
Dependent Credit = $40 ร number of dependents (1 or 2 max)
IA Tax (final) = max(0, Tax before credit โ Dependent Credits)
Example: Single filer, $70,000, 1 dependent
IA tax before credit: $67,790 ร 3.9% = $2,644
Dependent credit: 1 ร $40 = $40
IA tax final: $2,644 โ $40 = $2,604 | Effective rate: 3.72%
Iowa Old Brackets vs New Flat Rate
See exactly how much the 2026 flat tax saves compared to Iowa's old graduated brackets
Iowa's old graduated system had up to 4 brackets with rates from 4.4% to 6%, plus federal tax deductibility. Here's the direct comparison at your income level.
| System | Top Rate | Iowa Tax | Difference |
|---|
Old Iowa Bracket Detail (pre-2026)
| Bracket (Old) | Rate | Income in Bracket | Tax |
|---|
Old system calculation: uses old Iowa standard deduction ($2,130 single / $5,240 MFJ) and old brackets (4.4%โ6.0%), without federal tax deductibility (as it was phased out by 2026). This provides a like-for-like rate comparison.