What is the sales tax rate in Castle Rock, Colorado?

The combined sales tax rate in Castle Rock, Colorado is 8.100% as of 2026. This includes the Colorado state rate of 2.900% plus local jurisdiction taxes.

How is the Castle Rock sales tax calculated?

Multiply your purchase amount by 8.100% (or 0.00810) to get the tax owed. For example, a $100 purchase incurs $8.10 in sales tax.

What is the Colorado state sales tax rate?

The base Colorado state sales tax rate is 2.900%. Local jurisdictions may add additional taxes on top of this rate.

Does Castle Rock have a county sales tax?

Castle Rock imposes an additional county-level sales tax of 1.000% on top of the state rate.

When was the Castle Rock sales tax rate last updated?

The Castle Rock sales tax rate was last verified on March 27, 2026. We cross-reference all rates against the official State Department of Revenue data.

Live Data: April 2026

Castle Rock, CO Sales Tax Rate 2026

The combined sales tax rate in Castle Rock, Colorado is 8.100%.

Combined Rate 8.100%

State2.900% County1.000% City4.200%

Castle Rock Sales Tax Breakdown

Jurisdiction	Rate
Colorado State Sales Tax	2.900%
County Sales Tax	1.000%
City / Municipal Tax	4.200%
Total Combined Rate	8.100%

Which County Is Castle Rock In?

Castle Rock falls within Douglas, Colorado. Douglas imposes a 1.000% county-level sales tax in addition to the Colorado state base rate.

Castle Rock ZIP Codes

The following ZIP codes are mapped to Castle Rock for sales tax purposes. All listed codes apply the 8.100% combined rate.

80104 80108 80109

Nearby Tax Rates

Business Nexus in Colorado

Economic Nexus Threshold

Selling into Colorado from out of state? Once you exceed $100,000 in annual sales or 200 transactions, you must register and collect Colorado sales tax.

FAQ: Castle Rock Sales Tax

The combined sales tax rate in Castle Rock, Colorado is 8.100% as of 2026.

Multiply your purchase price by 8.100% to find the tax owed. A $500 purchase would include $40.50 in sales tax.

Groceries are generally taxable in Colorado. Check the official Department of Revenue for specific exemptions.

Vehicle purchases in Castle Rock are subject to the 8.100% combined rate, though some states apply different rules for vehicle sales. Verify with the Colorado Department of Revenue or DMV.

Register for a sales tax permit through the official Colorado Department of Revenue website. Registration is typically free and required before collecting any sales tax.

Sales Tax Calculator

Using 8.100% rate for Castle Rock, CO

Purchase Amount ($)

Tax Amount $0.00

Total with Tax $100.00

Rate applied: 8.100% combined

Official Tax Authority

Colorado Department of Revenue

Filing Deadline: Returns generally due the 20th. File via Revenue Online (ROL) portal.

Visit Official Portal (303) 238-7378