Sales tax in Boulder County, Colorado
There is no single sales tax rate in Boulder County. It runs from 5.335% to 9.585% depending on the exact address, because cities and special districts inside the county levy their own on top of the 2.9% state rate. The 2.9% state rate applies everywhere in the county; everything above that depends on where you are standing.
What is the sales tax rate in Boulder County?
| Colorado state rate | 2.9% |
|---|---|
| Boulder County rate | 1.335% |
| Lowest combined rate in the county | 5.335% |
| Highest combined rate in the county | 9.585% |
The two combined figures are the lowest and highest totals found anywhere inside the county. They are not a state rate plus a county rate added together, and adding the rows above will not reproduce them, because cities and special districts levy in between.
Why the rate here is not the whole story
Colorado charges 2.9 percent statewide and then stacks a county rate, city rates and special district rates whose boundaries do not follow county lines, so a single rate for the whole county does not exist. The county itself levies 1.335 percent countywide. The floor of 5.335 percent is at Jamestown, where the Regional Transportation District and the Scientific and Cultural Facilities District also apply. The ceiling of 9.585 percent is at Nederland, on top of the Regional Transportation District and the Scientific and Cultural Facilities District.
How do I find the exact rate for an address in Boulder County?
Because the rate changes within the county, an address is the only way to get it right. Use Colorado's own lookup. A vendor's calculator is not the state speaking.
Who has to collect sales tax in Boulder County?
A seller with a physical presence in Colorado collects at the rate for the address where the sale takes place. A remote seller collects once it passes Colorado's economic nexus threshold, which is a separate question from the rate and is covered on our sales tax nexus checker. Marketplace facilitators generally collect on behalf of their sellers.
How does Boulder County compare?
See Colorado sales tax for the statewide picture, including the average local rate and what is exempt. Property tax is a separate tax with separate rules: property tax in Boulder County.
Sources
- Boulder County rates: Colorado Department of Revenue, DR 1002 Colorado Sales/Use Tax Rates combined with DR 0800 jurisdiction codes, Colorado_Jurisdiction_Codes_Rates_July-Dec2026.xlsx, edition effective July 1 2026 through December 31 2026, https://tax.colorado.gov/sites/tax/files/documents/Colorado_Jurisdiction_Codes_Rates_July-Dec2026.xlsx
- Collected and verified September 9, 2026. Confidence: P on the rate components, P on the range (P read on a primary agency page, S strong but indirect, U unverified).