Colorado’s Amendment 87 would replace the state’s flat income-tax rate with six graduated brackets beginning in 2027. If you compare the ballot’s tax table with the examples in the state Blue Book, the figures may seem to disagree. They answer different questions: one shows averages for income groups; the other calculates tax on specific amounts of Colorado taxable income.
What would Amendment 87 change?
The official 2026 Colorado Blue Book says the proposal would replace the current 4.4% flat rate with marginal rates ranging from 3.7% to 8.4%. Each rate would apply only to income within its bracket. The proposal would also let the state retain and spend the additional revenue outside the TABOR limit for K–12 education, health care and early childhood programs. A “no” vote would keep the constitutional flat-tax requirement.
Why do the two tables look different?
The table printed in the ballot title reports average tax changes by federal adjusted gross income group. It groups many taxpayers together, and a joint return counts as one taxpayer in the state analysis. The Blue Book’s worked examples instead apply the proposed brackets to specific amounts of Colorado taxable income. Federal adjusted gross income and Colorado taxable income are not interchangeable.
For example, the Blue Book shows a taxpayer with $125,000 in Colorado taxable income owing $5,175 under the proposal, versus $5,500 under the current rate—a $325 difference. That example is a calculation for a specified taxable-income amount, not a promise that everyone in a similarly labeled income group would save $325.
At what income would tax owed rise?
The state fiscal impact analysis estimates that tax owed would decrease for Colorado taxable income below $510,834 and increase at $510,834 or above. The $500,000 bracket line and the $510,834 break-even estimate describe different things. Individual circumstances and tax subtractions can affect a return.
What about Social Security and other tax breaks?
Colorado currently has rules for subtracting qualifying Social Security income from state taxable income. The Blue Book does not directly explain how every existing subtraction would interact with Amendment 87. Do not infer a personal result from the ballot table alone; review the state’s current tax guidance and seek qualified advice for your own return.
How should you read the measure before voting?
Read the official Amendment 87 ballot analysis and compare its definitions before comparing dollar figures. For context on the state revenue limit, see our plain-language TABOR guide. Our judicial-retention guide covers a different part of the ballot.
Information checked Oct. 28, 2026. This article explains official public documents and is not individualized tax advice. Featured image is an AI-generated illustration.
