Colorado Property Tax Appeal Guide

What This Data Tells Us About Appeals in Colorado

In Colorado, property tax appeals are filed with the County Board of Equalization. The typical window is June 1 deadline for protests (odd-numbered reassessment years), with the deadline most commonly falling in June. Filing fees reported for this state are $0, and Lincoln Institute research plus state-reported data suggest roughly 45% of appeals result in some reduction when supported by comparable sales or documented errors.

Colorado reassesses every two years (odd years). If you miss the protest deadline, you cannot appeal until the next reassessment cycle. Appeals are driven by the gap between a parcel's assessed value and its actual market value — the calculator below turns that gap into an annualized dollar figure at your effective tax rate. The strongest evidence is three to five arms-length comparable sales from the past six to twelve months, plus documentation of any factual errors in the assessor's record (square footage, bedroom count, finished-basement status).

This guide is for informational purposes only and is not legal or tax advice. Deadlines, filing fees, success rates, and procedures vary by county within Colorado and can change year to year. Always verify the current rules with your local assessor's office — or a licensed attorney or tax professional — before filing. Source: Colorado Division of Property Taxation.