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Colorado 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.

How Bonuses Are Taxed in Colorado (2026)

A bonus paid on a separate check in Colorado has a flat 22% federal tax withheld (37% on cumulative supplemental wages over $1,000,000 in a year), 7.65% FICA, and Colorado's flat 4.4% state income tax. Withholding is not a higher tax rate — it is just how much your employer holds back up front; your actual tax on the bonus is settled when you file, and any over-withholding comes back as refund.

ComponentRate on the bonus
Federal income tax (supplemental, percentage method)22% flat  ·  37% above $1,000,000/yr
Social Security6.2% (up to $184,500 of total wages)
Medicare1.45%  ·  +0.9% above $200,000
Colorado state tax4.4% flat

Some employers instead use the aggregate method — adding the bonus to your regular paycheck and withholding as if that were every check — which can withhold more or less than the flat 22%. The calculator above uses the flat-rate (percentage) method.

Colorado Bonus Take-Home by Amount (2026)

Flat-rate (percentage) method, single filer, bonus paid separately on top of a $65,000 salary. Enter your own numbers in the calculator above — this table is a starting point.

BonusFederal (22%)FICAColorado taxTake-home
$1,000$220$77$44$660
$2,500$550$191$110$1,649
$5,000$1,100$383$220$3,298
$10,000$2,200$765$440$6,595
$15,000$3,300$1,148$660$9,893
$25,000$5,500$1,913$1,100$16,488

How Colorado Paycheck Tax Is Calculated (2026)

Source: Colorado Department of Revenue
Flat state rate4.40%
Standard deduction (single)$16,100
state_tax = max(0, gross_income - 16100) × 0.044

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

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

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

Colorado Bonus Tax FAQ

How much are bonuses taxed in CO?

A separately-paid Colorado bonus has a flat 22% federal supplemental tax withheld (37% above $1,000,000/year), 7.65% FICA, and Colorado's flat 4.40% state income tax. Colorado does not publish a separate supplemental rate, so 4.40% applies. Combined withholding is roughly 34%.

What is the Colorado bonus tax rate for 2026?

Federal flat 22% + Colorado flat 4.40% + Social Security 6.2% + Medicare 1.45%. On a $5,000 bonus that is about $1,100 federal, $220 Colorado, and $383 FICA withheld.

Is a Colorado bonus taxed at a higher rate than salary?

No. Colorado's 4.40% is a true flat tax that applies to a bonus and to salary identically. Only the federal withholding method differs - separate bonuses use the flat 22% supplemental rate instead of the wage-bracket tables.

Methodology & Source

Colorado state tax figures sourced from Colorado Department of Revenue (https://tax.colorado.gov/), citing Colo. Const. art. X (flat rate mandate) — 4.4% per Proposition 121 (2022). 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). Colorado'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. Colorado publishes no separate supplemental withholding rate, so the calculator estimates the state tax on the bonus from your marginal bracket.

This is an estimate based on standard single-filer federal, FICA, and CO state calculations. Actual withholding may differ based on your W-4 elections, pre-tax deductions, and other factors. Colorado starts from federal taxable income; this estimate applies the federal standard deduction as the base. Colorado's TABOR mechanism can temporarily lower the effective rate in high-revenue years, not modeled here.

Guideline version: 2026-CO-v1 · Effective: 2022-01-01 · Last verified: 2026-07-26