Colorado assessors mail Notices of Valuation by May 1 — and give you until June 8 to protest, free, right on the notice. For 2026, every county must value your home as of June 30, 2024. If the market says less, our free tools help you prove it.
Mailed by May 1, it shows the actual value the assessor set — for 2026, as of the June 30, 2024 appraisal date. The protest form is printed right on it.
Comps must bracket June 30, 2024 (the statutory level of value). County assessor sites publish the sales they used — find better ones in the worksheet below.
Online, by mail (postmark counts), or in person with your county assessor. The assessor answers with a Notice of Determination by the end of June.
Denied? Appeal to the County Board of Equalization by July 15. After that: state Board of Assessment Appeals, binding arbitration, or district court — your choice.
Colorado reassesses on a two-year cycle: 2025 and 2026 values are both pegged to June 30, 2024 (§ 39-1-104, C.R.S.). Sales from 2025-2026 generally don't count — your evidence must show what the home was worth in mid-2024. Choose comps accordingly.
Everything runs in your browser — we never see or store your property data.
Colorado taxes assessed value (6.25% of actual value for local levies, 7.05% for schools in 2026) at local mill levies — statewide effective rates average roughly 0.5% of market value, among America's lowest. Enter your county's effective rate for a tighter estimate. Estimates only; not tax advice.
Enter sales of similar homes near the June 30, 2024 level-of-value date (county assessor sites publish the sales they used — Denver, Boulder, El Paso, Jeffco all have search tools). The worksheet computes price per square foot and a suggested value.
| Address | Sale Date | Sale Price ($) | Sq Ft | $/Sq Ft |
|---|
| Item | Colorado Rule |
|---|---|
| Notice of Valuation | Mailed by May 1 by your county assessor — protest form printed on it |
| Protest deadline | June 8 — online, in person, or postmarked by 11:59 p.m.; free |
| Assessor's answer | Notice of Determination mailed by the end of June |
| Next level | County Board of Equalization by July 15; hearings conclude by early August |
| After CBOE | Board of Assessment Appeals, binding arbitration, or district court (30 days) |
| Level of value | 2025 & 2026: June 30, 2024 (two-year reassessment cycle, § 39-1-104) |
| Assessment rates | Residential 2026: 6.25% local / 7.05% school (non-residential 27%+) |
| Records | County assessor property search portals publish values, characteristics & comp sales free |