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NOTE: There is no change to the due date for filing sales and use tax returns. Returns and payment are due on the 20th of each month. Please file your monthly sales and use tax return with the City as usual. If full payment is not included, the City will waive penalties and interest as long as the tax filer files the return and makes contact with the City to make payment arrangements. (3/19/20)


As an entity engaged in business within the City of Longmont, you are required to have a Sales and Use Tax License. This applies to retailers, manufacturers, wholesalers, contractors, professionals, and service businesses. Charitable, nonprofit and tax-exempt entities also are included.

City of Longmont Sales Tax Rates - Effective January 1, 2018
City of Longmont = 3.53%
State of Colorado = 2.90%
RTD = 1.00%
Cultural District = 0.10%
Boulder County = 0.985%
TOTAL Combined Sales Tax Rate in Longmont: 8.515%



   Online application ..... Instructions for applying online
   PDF application
   Excel application

Return the completed form in person (8-5, M-F) or by mail: Longmont Sales Tax Division, 350 Kimbark St., Longmont, CO 80501

There is a one-time processing fee of $25, which may be paid by cash or check. For assistance, please contact the Sales Tax Office at 303-651-8672 or email You also can visit the Sales Tax Office in the Longmont Civic Center at 350 Kimbark Street. 

File and pay your sales and use taxes online

Municipal Code/Sales and Use Tax:
View the City's Municipal Code relating to Sales and Use Tax. 

The City of Longmont is located in two counties with four USPS ZIP codes, two of which also appear in areas outside of the city and do not coincide with city boundaries. However, in some cases these locations use “Longmont” as the city name. Therefore, you cannot rely on the mailing address and ZIP code to determine whether or not a particular location is within the city boundaries (see city boundary map). This can cause difficulties in determining whether or not a transaction is subject to the City of Longmont sales tax.

Businesses are liable to the City for sales tax that is undercollected. Please consult the electronic location databases that have been certified by the Colorado Department of Revenue pursuant to Colorado Revised Statutes 39-26-105.3 to determine the correct jurisdiction for sales tax purposes. The City of Longmont, along with several other municipalities, has put in place provisions that will hold harmless businesses that collect the incorrect amount of sales tax if they can offer proof that the most current version of these databases was used and provided the incorrect information for a particular address.

For additional information about using currently certified database providers, along with links to these providers' websites, please visit the Colorado Department of Revenue.

Looking for information on property taxes? Boulder County Assessor's office:

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