Tax Law ✦ Colorado
Colorado Tax Is Simple on Paper. The Details Are Not.
A flat income tax, no estate tax, and a pass-through election that restores the federal SALT deduction make Colorado a friendly state to plan in. Then there are 70 home-rule cities collecting their own sales tax, TABOR rate changes, and a Department of Revenue that assesses every IRS adjustment plus a year. North Star Law Firm handles the Colorado side of every federal engagement and the state-tax planning that stands on its own.
Overview
The Colorado tax system for someone who has to live with it
Colorado’s income tax is one of the simplest in the country: a flat rate applied to federal taxable income with a defined list of additions and subtractions, administered by the Department of Revenue through Revenue Online. There is no local income tax, no estate or inheritance tax, and no franchise tax. The state’s difficulty is on the transaction side, where sales and use tax is administered by the state for some jurisdictions and by roughly 70 home-rule municipalities for themselves, and on the enforcement side, where a federal adjustment produces an automatic Colorado assessment with its own protest deadlines. We handle the planning (the PTE election, the retirement and capital gain subtractions, sales tax setup) and the disputes (protests, conferences, hearings) as part of a federal engagement or on their own.
- Colorado additions and subtractions optimized each filing season
- SALT Parity Act pass-through entity election evaluated and made
- Sales and use tax registration and compliance for home-rule cities
- Federal change reporting and amended Colorado returns after an IRS audit
- Protests of DOR notices of deficiency and refund denials within the 30-day window
- Tax Conferee conferences and Executive Director hearings
- Colorado offers in compromise and payment plans
- Coordination with Colorado-licensed counsel on state-court appeals and state-law documents
At a Glance
The Colorado tax picture
| Tax | Rate / rule | What matters in practice |
|---|---|---|
| Individual income tax | Flat rate on federal taxable income (4.40% statutory; 4.25% for 2024 under a TABOR reduction; 4.40% for 2025; later years per that year’s TABOR determination) | No brackets, so planning is about the base: subtractions, timing, and the PTE election |
| Corporate income tax | Same flat rate on federal taxable income, apportioned by single-factor sales | C corporations with out-of-state sales apportion income; combined reporting rules apply |
| Trusts and estates | Same flat rate; fiduciary return (DR 0105) | Colorado resident trust rules and the distribution deduction follow federal Form 1041 |
| Estate and inheritance tax | None | Planning is federal only; Colorado adds no second layer |
| Sales and use tax | 2.9% state plus county, district, and city taxes; ~70 home-rule cities self-collect | Registration, sourcing, and audits vary by city; SUTS covers participating cities |
| Property tax | Assessed by county on a state-set assessment rate | Low effective rates; residential and commercial rates set by the legislature and subject to frequent change |
| Assessment period | One year after the federal period (C.R.S. § 39-21-107); refunds within 4 years of the due date | Federal changes must be reported within 30 days; unreported changes keep the period open |
The Attorney-CPA Difference
State tax is where a federal case gets a second bill.
Every IRS adjustment we negotiate produces a Colorado amended return, and every collection resolution we reach has a Colorado counterpart with different rules: a state OIC that is one-time only and doesn’t pause collection, payment plans on shorter terms, a protest clock that runs from the mailing date. Because we prepare the returns and negotiate the resolutions ourselves, the Colorado piece is handled as part of the same engagement rather than left for later.
- Colorado consequences computed with every federal resolution
- Amended Colorado returns filed on the 30-day federal-change deadline
- PTE election and subtractions reviewed annually
- Home-rule sales tax compliance set up and audited defensively
- Colorado-licensed counsel brought in for state-court and state-law work
Questions & Answers
Colorado State Tax & DOR Matters questions, answered
What is Colorado’s income tax rate?
A single flat rate on federal taxable income for individuals, estates, trusts, and corporations. The statutory rate is 4.40 percent. In years when the state collects more than its TABOR limit, the rate can be temporarily reduced as a refund mechanism: it was 4.25 percent for tax year 2024 and returned to 4.40 percent for tax year 2025, as the Department of Revenue’s 2026 individual income tax guide confirms. A 2025 bill that would have made 4.25 percent permanent was postponed indefinitely and never became law. Because each year’s rate depends on that year’s TABOR determination, we confirm it for the year in question rather than assume it.
What are the main Colorado additions and subtractions?
Colorado starts from federal taxable income, then adds back items like state income tax deducted federally and certain federal deductions limited for higher earners, and subtracts items like a portion of pension and annuity income, Social Security benefits for taxpayers 65 and older, and, for farmers who file Schedule F, capital gains on Colorado agricultural land held at least five years (the broader capital gain subtraction ended after 2021). The list changes with the legislature, so we review it every filing season.
What is the PTE election and should my business make it?
Under the SALT Parity Act, a partnership or S corporation can elect to pay Colorado income tax at the entity level, and the owners then claim a credit on their Colorado returns. The point is federal: the entity-level state tax is a deductible business expense, so the owners get a full federal deduction for state tax that would otherwise be limited on Schedule A. It is worth making for most profitable Colorado pass-throughs with owners who itemize; the election is annual and tied to the federal SALT cap, so its value has to be checked each year.
Why is Colorado sales tax so complicated?
Because of home rule. The state rate is 2.9 percent and the Department of Revenue collects county and special district taxes with it, but about 70 home-rule cities, including Denver, Aurora, Colorado Springs, Fort Collins, and Boulder, collect their own sales and use tax under their own definitions, exemptions, and audit programs. A business selling in several cities may face several sets of rules. The state’s SUTS portal simplifies filing for cities that participate, and we set up the compliance so it is manageable.
How do I dispute a Colorado Department of Revenue notice?
File a written protest with the Executive Director within 30 days of the mailing date of the notice of deficiency or refund denial. The protest stays collection, goes to the Tax Conferee section for review and an informal conference, and proceeds to a formal hearing in Denver if not resolved. A final determination can be appealed de novo to district court within 30 days under C.R.S. § 39-21-105. We handle the tax accounting and administrative side and coordinate with Colorado-licensed counsel where the matter requires it.
Plan the tax before the transaction, not after.
A free consultation with an attorney-CPA who can draft the structure and run the numbers in the same meeting.