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Iowa Bonus Tax Calculator

Estimate take-home pay on a bonus, using the federal flat-rate supplemental withholding method

Estimate only — not tax advice. Federal tax on the bonus uses the flat 22% supplemental withholding rate (37% on cumulative supplemental wages over $1,000,000/year) — the alternative "aggregate method" some employers use instead is not modeled. FICA and any state SDI/PFL are computed as the difference between your regular income with and without the bonus added, so the Social Security wage cap applies correctly. State tax on the bonus is a marginal-bracket estimate, not necessarily any special state supplemental rate. See methodology below for source and last-verified date.

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Paid hourly? Try our Iowa hourly paycheck calculator →

How Iowa Paycheck Tax Is Calculated (2026)

Source: Iowa Department of Revenue
Flat state rate3.80%
Standard deduction (single)$16,100
state_tax = max(0, gross_income - 16100) × 0.038

Federal Tax & FICA (shared across all states)

Filing statusStandard deduction
Single$16,100
Married Filing Jointly$32,200
Head of Household$24,150
Federal brackets (all filing statuses)10% / 12% / 22% / 24% / 32% / 35% / 37%
Social Security6.2% up to $184,500 wage base
Medicare1.45% on all wages, +0.9% above $200,000 single/HoH, $250,000 MFJ

⚠️ Iowa's married-filing-jointly and head-of-household state brackets have not yet been independently verified against the primary source above — this calculator uses Iowa's single-filer brackets as an estimate when those statuses are selected.

⚠️ Many Iowa school districts levy a local income surtax, typically 1%-20% of your Iowa state tax liability (not of wages directly) — varies by district and not computed here.

Guideline version 2026-IA-v1 · Last verified 2026-07-26

Iowa Paycheck Calculator FAQ

What is Iowa's state income tax rate?

Iowa charges a flat 3.80% rate for tax year 2026. Standard deduction: $16,100 for single filers.

How much is take-home pay on $65,000 in Iowa?

On a $65,000 gross salary, a single filer in Iowa takes home roughly $52,549.3/year (about $4,379.11/month) after federal tax, FICA, and state tax.

What deductions does Iowa apply before taxing my income?

Iowa applies a $16,100 standard deduction, before the flat 3.80% rate. See the "How Iowa Paycheck Tax Is Calculated" section above for the exact formula.

Does this estimate change if I'm married or have dependents?

This calculator uses single-filer figures only (v1 scope). Married filing jointly typically uses different federal and Iowa state brackets and a larger standard deduction — your actual take-home pay will differ. Dependents can also reduce federal withholding via the W-4. Check Iowa Department of Revenue's married-filing-jointly tables for a precise figure.

Methodology & Source

Iowa state tax figures sourced from Iowa Department of Revenue (https://revenue.iowa.gov/), citing SF 2442 (2024) — flat 3.8% effective 2026, completing the phase-down from a 6-bracket system topping out at 8.53%. Federal brackets, standard deductions (single/MFJ/HoH), and FICA constants sourced from the IRS (Revenue Procedure 2025-32; married-filing-jointly Additional Medicare threshold of $250,000 is a separate, unindexed statutory figure). Iowa's married-filing-jointly and head-of-household figures are not yet independently verified and currently fall back to single-filer brackets — see the caveat in the formula section above.

Bonus federal withholding uses the flat supplemental-wage rate (22%, 37% above $1,000,000 cumulative supplemental wages/year), per IRS Publication 15 (Circular E), Employer's Tax Guide, 2026 edition — the alternative "aggregate method" is not modeled.

This is an estimate based on standard single-filer federal, FICA, and IA state calculations. Actual withholding may differ based on your W-4 elections, pre-tax deductions, and other factors.

Guideline version: 2026-IA-v1 · Effective: 2026-01-01 · Last verified: 2026-07-26