Sales Tax in Castle Rock, Colorado in 2025

We'll walk you through how the sales tax rate is determined for Castle Rock and address some common questions you may have. We'll also cover how to collect, audit, and remit sales tax in Castle Rock.

Plus, we’ll share the best solution that will ensure you are always compliant across the entire sales tax lifecycle.

Disclaimer: Our sales tax data is updated on a quarterly basis.

Castle Rock Sales Tax Rate 2025

Castle Rock is located in Douglas County in Colorado, United States, and has a sales tax rate of 7.90%. This includes local and state sales tax rates.

Here is the breakdown of the Castle Rock's sales tax:

Tax Jurisdiction	Sales Tax Rate
State Tax	2.90%
County Tax	1.00%
City Tax	4.00%
Combined Rate	7.90%

This rate applies to the following zip codes in Castle Rock:

80104, 80134, 80108, 80109, 80116

How Does the Castle Rock Sales Tax Compare to the Rest of Colorado?

Castle Rock’s 7.90% sales tax rate is 3.65% lower than the highest sales tax rate in Colorado, which stands at 11.55% in cities like Central City.

It is 5.00% higher than the lowest sales tax rate in Colorado, which stands at 2.90% in cities like Sheridan Lake.

To give you a better idea, here’s a comparison of Castle Rock sales tax rates with a few other cities in Colorado:

City	Sales Tax Rates
Sheridan Lake	2.90%
Paoli	3.90%
Hugo	6.90%
Castle Rock	7.90%
Littleton	8.00%-8.75%
Crested Butte	9.40%
Silverton	10.40%
Central City	8.90%-11.55%

You can also compare the sales tax rate of Castle Rock against the Colorado cities closest in population size:

• Boulder's sales tax rate is 9.05%
• Longmont's sales tax rate is 7.43%-8.72%

What Creates Sales Tax Nexus in Castle Rock?

Castle Rock has the same sales tax nexus rules as Colorado. 

Read More: Check out this detailed guide on Sales Tax in Colorado.

You have sales tax nexus in Castle Rock if you meet one of the following conditions:

• Physical nexus: Businesses with a physical location in Colorado must follow all sales tax licensing and collection rules if the retailer maintains any place of business in the state directly, indirectly, or by a subsidiary. A place of business may include an office, distribution center, salesroom, warehouse, storage space, or even a home office of a Colorado-based employee. 
• Employees: A retailer will have nexus through an employee who is a salesperson or a representative of the business.
• Economic nexus: Businesses must collect Colorado sales tax if their retail sales into the state during the current calendar year exceed $100,000. 

What Products Are Exempt from Castle Rock Sales Tax?

Castle Rock follows the same sales tax rules as Colorado and doesn't have any special exemptions. 

The items exempt from sales tax in Castle Rock are:

• Food purchased for human consumption, except for hot food ready to be eaten or heated in the store. 
• Gas, electricity, coal, wood, and fuel oil sold for residential use. 
• All prescription drugs dispensed by a practitioner with a valid prescription. 
• Certain medical supplies and materials.
• Farm equipment, such as farm tractors, irrigation equipment, dairy equipment, and more.

Who Needs a Sales Permit in Castle Rock?

You need a sales permit if you are a retailer located in Castle Rock or if you have a sales tax nexus.

You can register for a sales tax permit online via the Colorado Department of Revenue Website or offline by submitting form CR 0100. 

How to Collect Sales Tax in Castle Rock

Colorado is a destination-based sales tax sourcing state. 

This means that when you make a taxable retail sale to a customer in Castle Rock, whether from outside or within the state, you must apply the sales tax rate according to the buyer's shipping address.

Learn more about origin-based and destination-based sales tax sourcing here.

How to File and Pay Sales Tax in Castle Rock

You can file Castle Rock sales tax returns using the following methods:

• Automated: Let Zamp handle your Colorado sales tax filing and remittance so you won’t have to deal with sales tax returns ever again.
• Online: If you have more than one business location, you must file a separate return in the Revenue Online Website for each location.
• Approved Sales Tax Software: Vendors with multiple locations can use Approved Sales Tax Software, which will automatically generate electronic XML files that can be uploaded to Revenue Online.
• Sales Tax Spreadsheet E-Filing: Multiple location filers who don’t use the Approved Sales Tax Software can use Sales Tax Spreadsheet E-Filing.
• Offline: You can select the applicable forms and mail them to:
  Colorado Department of Revenue
  
  Denver, CO 80261-0013